Main Blog

This is my blog concerning my work with ice age glaciers. The main blog is www.markmeeksideas.blogspot.com . If you like this blog, you may also like my geology blog, www.markmeekearth.blogspot.com and my Niagara area natural history blog, www.markmeekniagara.blogspot.com .

NOTICE: This is a blog with the older formatting. To see all of the postings on the blog listed, look at the list of postings on the right and click on the bottom one, other than the archives. This will display the rest of the postings. The final posting on the blog is "The Slopes Of Tonawanda And Buffalo".

What Caused The Ice Ages?

Here is one of those questions of the ages. On a roughly regular basis, the earth grows colder until it enters a so-called "ice age" maybe 8,000 years in duration.Then, it grows warmer until the ice age ends and a warm period of about 15,000 years follows. After this, the cycle repeats over and over again. These ice ages began somewhat suddenly in the earth's history.

The question is: why? There are a number of theories that you may read about in the article about the ice ages on www.wikipedia.org if you wish. Many believe that it is factors outside the earth that are responsible for the ice ages such as variations in the output of the sun or perturbations in the orbit of the earth around the sun.

I just cannot believe this. I have long been certain that there must be some cyclic process on earth that bears the primary responsibility, for one thing no signs of any alternating cold periods have been found on other planets. I have written about this previously, but today I would like to introduce a complete theory of the ice ages.

The ice ages, and the massive glaciers that it produces, does a lot to shape the landscape of much of the earth's surface. During the warm periods about 10% of the earth is covered by ice, but this increases to about 30% during the ice ages.

Glaciers begin to form when it gets cold enough so that the snow of one winter has not completely melted by the time the following winter begins. Snow begins to pile up year after year, decade after decade and, century after century. The snow in the lower levels is compressed into ice by the weight of the snow above it. The eventual result is a massive sheet of ice stretching across the landscape and two or three kilometers in height. When an object is large enough, it is affected by the rotation of the earth and the glaciers are pulled toward the equator and somewhat to the east by the earth's rotation.

The white surface of the snow and ice reflects a lot more solar radiation back to space than the darker ground beneath. Thus, we get a cooling spiral started which forms still more ice. This ice does not flow through the watershed back to the sea, as it would if it were rainfall. This causes a drop in sea level of maybe a couple of hundred meters, and leaves a lot of land connections that were not there during the warm periods such as the land bridge across the Bering Strait and a land connection from mainland Asia to Japan.

It is fairly easy to explain why the ice ages began. We know that the carbon dioxide in the atmosphere acts as a greenhouse gas, and causes the earth to warm. Basically, the earth absorbs radiation from the sun each day and grows warm. The earth re-radiates this radiation back into space, but does so at different wavelengths than the incoming radiation. A greenhouse gas in the atmosphere, like carbon dioxide, causes the earth to get warmer by allowing the incoming wavelengths through but blocking the outgoing wavelengths so that heat is trapped.

Much of the structure of plants is carbon. Leaves use energy from the sun to split molecules of carbon dioxide, releasing the oxygen back into the air and using the carbon to build the structure of the plant. Dead plants may become buried or submerged before they can decay. This is how limestone (calcium carbonate), coal and, oil form over long periods of time, and when this happens carbon is removed from the air.

Could it be that the earth was once warmer than it is today because of a higher level of carbon dioxide in the air, but it began to cool when enough carbon became buried as the dead plants which formed coal and oil? This could have reached a point which got the ice ages underway. Of course, we are in the process of reversing this by burning fossil fuels and bringing about global warming.

We have seen how the ice ages began. But that still does not explain why the earth gets colder and than warmer in a recurring cycle. However, I have noticed a simple explanation.

We know that plants pull carbon dioxide out of the air as they grow. The carbon is incorporated into the structures of the plants, while the oxygen that it is separated from is circulated back into the air. When the plant dies and decays, the carbon is oxidized and returns to the air as carbon dioxide.

Now, here is the question to ponder: What about the roots of the plants? The structure of the dead plant that is above ground decays back into the carbon dioxide from which it was formed, but the roots remain under the ground. The roots will also decay, but most of the carbon of which they are composed will be blocked from returning to the air and will remain in the ground.

This is the reason that plowing the soil releases so much carbon dioxide, the carbon from long-decayed roots of dead plants is being released back into the air. My hypothesis is that, when enough carbon is removed from the air as plant roots, the earth cools enough to bring about another ice age.

It is no secret that the most fertile lands on earth are those over which glaciers have moved during the ice ages. The reason is that the nutrients that are vital to plants tend to get lost in the soil over time, and the plowing done by a moving sheet of ice brings the nutrients back up. But if this glacial plowing brings back nutrients to near the surface, think of how much carbon dioxide it must release also. All of the carbon from the decayed roots of countless generations of dead plants would suddenly be released, just as if the soil were being plowed with a giant plow.

The arctic regions are not the only source of glaciers during ice ages. The same effect takes place as vast sheets of ice form by the glacial process in mountainous regions, due to the higher and colder air. We saw this in the posting "Mountains And Glaciers", on this blog.

The next factor that comes into play is earthquakes. Most mountains, unless of volcanic origin, are formed by tectonic collisions that are still, more or less, taking place. Thus, the mountainous regions that host extensive glaciers during the ice ages are especially prone to earthquakes, which do not stop just because it is an ice age.

What happens is that the earthquakes jolt glaciers loose so that they slide down to the lowlands below, and in doing so plow the soil to great depth so that thouands of years of carbon dioxide from decayed plant roots is released into the air. This causes the earth to warm because carbon dioxide is a greenhouse gas, and this ultimately brings about the end of the ice age.

This process brings about a spiral. The plowing of adjacent lowlands by glaciers from mountains, knocked loose by earthquakes during the ice ages, also brings nutrients to the surface. This makes the area fertile so that plants will flourish during the ensuing warm period, and will leave even more carbon in the ground as the roots of the plant after the end of it's life.

Just by looking at a map, it is easy to see the link between earthquakes in mountainous regions and glacial activity in the lowlands below. Here is a map link: www.maps.google.com .

Argentina has a vast continental shelf, which could have easily been formed as the land was carved away by moving glacial ice, that is about as large as the country itself. Argentina happens to be just east of the Andes Mountains, which undergo the extremely powerful earthquakes of a subduction zone such as the 2010 Chile earthquake. Momentum from the earth's rotation would pull the loosened glaciers eastward, across Argentina.

Greece is also vulnerable to earthquakes. The Aegean Islands are on a shallow shelf that has been mostly carved away by glacial activity. Crete appears to be the furthest extent of the shelf. Glaciers from the mountains to the northwest, pulled by the earth's rotation to the south and east after having been shaken loose by earthquakes during the ice ages, carved away most of the landscape and left the islands.

Italy, as well as Greece, is on a tectonic plate that is vulnerable to earthquakes. The Adriatic Sea is actually a shallow glacial raceway, formed where the ground has been carved away by glacial movement toward the south and east through the gap between the mountains of Italy and those of the former Yugoslavia. Glaciers from the mountains all around, especially the Alps, were shaken loose by earthquakes and pulled by the momentum of the earth's rotation to the south and east.

The Persian Gulf region is the site of heavy glacial activity, which plowed the ground to produce what is known as the Fertile Crescent and eroded away what is now the shallow Persian Gulf in much the same way as the Adriatic Sea. The glaciers came from the nearby Zagros Mountains of Iran, which is very vulnerable to earthquakes, and were pulled by the momentum of the earth's rotation to the south and east.

The mountains of south China must have hosted extensive glaciers during the ice ages, and are also very vulnerable to earthquakes. I pointed out the route of the Red River in "Mountains And Glaciers". A wide area was carved away by the glaciers, knocked loose by earthquakes and pulled by the earth's roation to the south and east, leaving Hainan Island intact and leaving Vietnam with a wide and shallow continental shelf.

North China is generally less vulnerable to earthquakes than the south. But it appears logical that earthquakes jolted mountain glacial ice loose during the ice ages to carve the shallow extension of the Yellow Sea known as the Bo Hai, near the cities of Dalian and Tianjin.

In contrast, the Rocky Mountains of North America are not known for earthquake activity and no evidence of such glacial activity is to be seen nearby. Neither is there any sign of large-scale glacial activity around the Adirondack Mountains of New York State or the mountains of New England. The area is very mildly seismic, but no large earthquakes.

The area around the Appalachian Mountains do not display any signs of such glacial activity, except for the pair of Chesapeake and Delaware Bays. But these were formed by glacial movement being focused by the curve in the Appalachians across Pennsylvania, and are nowhere near the scale of the glacial activity described above.

So, there can be no doubt that there is extensive glacial activity that can be seen to have taken place around mountains that would have hosted extensive glaciers during the ice ages and that are vulnerable to earthquakes. Since the most fertile areas in the world are those which have been plowed by glaciers, and since plowing soil is known to release large mounts of carbon dioxide into the air, we can safely assume that plowing by glaciers releases carbon in the soil that has built up during the warm periods between the ice ages, and that this is ultimately what brings the ice age to it's end until the carbon is put back into the soil by the remaining roots of dead plants during the warm period, and this ultimately brings on the next ice age. The plants thrive in this area because the glacial plowing that released the carbon also brought buried nutrients to near the surface.

How else can the recurring cycle of ice ages and warm periods be explained? Isn't this the most logical explanation? Isn't it amazing that without earthquakes there would be a continuous ice age?

Weather Patterns During The Ice Ages

What about weather patterns during the ice ages? If the temperature dropped dramatically and the earth's ice cover increased, it would certainly change the weather patterns that we are familiar with today.

I have noticed how we can take a look into the weather patterns during the ice ages just by looking at a map.

The Rhone Valley is wide and broad and runs north-south across southeastern France between the Massif Central and the Alps. The valley is parallel to the French-Italian border and extends from the city of Dijon through Lyon to Marseilles on the Mediterranean coast.

The Mistral is the wind which passes through the Rhone Valley from the north. The wind can, at times affect lands across the sea such as Sardinia and even north Africa. You can read more about the Mistral if you wish by going to http://www.wikipedia.org/ and entering in "Mistral (wind)".

My hypothesis is that the Mistral must have been far more powerful during the ice ages than it is today, and that gives us a clue as to the weather patterns as a whole during the ice ages.

Let's briefly review the formation of glaciers during the ice ages. Glaciers begin to build when the temperature drops low enough so that the snow of one winter has not completely melted when snow begins to fall the following winter. This means that snow continues to pile up, year after year and century after century.

Snow is compacted into ice by the weight of the snow above it. Eventually, a vast and thick sheet of ice has formed that is wide enough to be affected by the rotation of the earth. The ice sheet is pulled southward, toward the equator, and along with the eastward rotation of the earth. (For more on this, see "New Discoveries Concerning Glaciers" on the glacier blog). All the while, the white snow and reflective ice contributes to the cooling spiral by reflecting solar energy back into space instead of absorbing it.

In the posting "Mountains And Glaciers" on this blog, I explained how glaciers can form much further south than they ordinarily would at ground level if there are mountains with sufficient altitude that can provide a suitable site for glacier formation.

Now, let's go across the Mediterranean Sea from the Rhone Valley to the mountains of Algeria. Here is a map link, http://www.maps.google.com/ , or you can follow along in a physical geography world atlas.

South of the city of Algiers, there is a lake in the Atlas Mountains. The name of the lake in Arabic is Chott El Hodna. Moving south and east, to the south of the mountain range on lower ground is Chott Melrhir, Chott El Gharsa, Chott Jerid and, Chott Fejaj.

This line of lakes extends from northwest to southeast, just what we would expect if the lakes were formed by glacial movement out of the mountains and guided by the earth's rotation, and end at the Golfe de Gabes on the east coast of Tunisia. The directional alignment of the string of lakes clearly shows this glacial movement and the Golfe de Gabes also appears as an outlet of this glacial movement to the sea.

Notice that Chott El Hodna, in the mountains south of Algiers, is on a straight line with the Rhone Valley if it were extended across the Mediterranean Sea. There must have been very heavy snowfall in the Altas Mountains to form the glaciers which carved this string of lakes. Since the area is mostly dry today, other than these lakes, my conclusion is that the Mistral was much more powerful and consistent during the ice ages than it is today.

Now, let's go far away, to Buffalo, NY. The thing that made me think of this scenario is the lake-effect snow that Buffalo is known for during the winter. The prevailing wind in the area is from the west, so that it sweeps across the length of Lake Erie before arriving at Buffalo. When the lake is warm but the air passing over it is cold, it picks up more water than it can hold.

When the air reaches the eastern end of the lake and passes over land, which loses heat faster than water and so is colder, the air becomes unable to hold the water vapor (vapour) that it has collected. The result is all-too-familiar to residents of the area, tons and tons of snow dropped on Buffalo and the Southern Tier of New York State, down to around the Pennsylvania state line.

Lake Erie is the shallowest of the Great Lakes, and the only one that freezes over, and when it does the lake-effect snow ceases because the ice covering the lake prevents further evaporation. There is actually more snowfall in central New York State than there is is Buffalo because they get their lake-effect snow from Lake Ontario, which is too deep to freeze over during the winter.

The basin of the Mediterranean Sea is too deep, and too far south, to freeze over during the ice ages. A similar phenomenon to Buffalo's lake-effect snow happened here during the ice ages. The powerful, cold Mistral passed over the warmer sea. It picked up a lot of water until it reached the Atlas Mountains, south of Algiers.

Altitude was also a factor here, higher and thinner air can hold less water. A vast amount of snow was dropped in the mountains. This snow formed the glaciers, which were moved by the rotation of the earth to form the string of lakes that we can see on the map today.

Glaciation And Building Construction

You can tell a lot about the movement of glaciers over an area during the ice ages, the most recent of which ended about 12,000 years ago, just by observing the traditional construction in the area.

In some areas, there are many loose stones to be found in fields and just under the ground. Whenever farmers plow (plough) their fields, or other digging is done, such stones are uncovered and are used for building walls, chimneys and, entire structures.

Such loose stones are found when an advancing glacier, at the beginning of an ice age, chips stone off a mountain or escarpment of some type, carries it along, and then leaves it at the end of the ice age when the ice melts. These loose stones are very often rounded, which is the result of flowing water from the melting of the glacial ice and from any temporary lakes that may have formed.

In one ice age after another, this process is repeated until there is enough loose stone to build entire towns from. This does not, of course, include flat stones which are taken from stone quarries. That stone is from the underlying rock strata and has nothing to do with glaciation.

Even if an area is covered by ice during the ice ages, this mass deposit of loose stone will not take place unless the moving ice first passes through mountains, or other exposed stone, that it can chip away at. Much loose stone is found all across Britain because the ice passed through such mountains as those of Scotland and the Pennines. This concept enables us to track glacial movement simply by looking at the type of typical traditional architecture in a given area.

Norway is mountainous and far to the north, so that it would certainly be involved with glaciation. Yet, traditional Norwegian architecture is focused much more on wood than stone. This confirms what I wrote in "New Discoveries In Europe Concerning Glaciers", on the glacial blog.

Ice moving from the northwest bounced off the Norwegian Mountains. The mountains themselves would have produced glaciers, which moved southeastward toward the border with Sweden. But this ice did not come across much rock to chip away at and carry with it. If the main glacial movement had gone right through the Norwegian Mountains, it would have chipped off a considerable amount of loose stone, and this would be seen today in the traditional architecture of the region. Further south, in northern Europe, there is also less rounded stone to be seen in the traditional architecture than there is in Britain, and this also fits this scenario.

Ireland had it's landscape just as swept by glacial ice as Britain. The reason that loose, rounded stone is less to be found in it's architecture can easily be seen on a map. The movement of ice toward Ireland from the northwest did not pass by exposed stone, as the ice that crossed Britain did.

Very large boulders can also be moved by glacial ice. Near Niagara Falls, on Goat Island, there is such a boulder. The stone of which the boulder is composed does not match that of any stone in the area. But in northern Ontario, there is a native stone that matches that of the boulder. It was moved to it's present location, far to the south, by the ice age glacial movement.

In Appreciation Of The Canadian Shield

The Canadian Shield is the expansive area of dense rock that underlies approximately the eastern half of Canada. I think it is appropriate to point out how very important to us this mass of rock is. I encourage Canadian readers especially to read the article about the shield on http://www.wikipedia.org/ .

I can show you what the majority of Canada would look like if it were not for the Canadian Shield, and it is not an appealing sight. On http://www.maps.google.com/ , you can see a vast area of shallow sea all around northwestern Europe. This includes the North Sea and the Baltic Sea. There is also an area of shallow sea to the west of Ireland that is about as big as Ireland itself.

This area of shallow sea was once all dry land, but it has been carved away by the movement of glaciers during the ice ages. All that remains today of this former land is Britain, Ireland and, Scandinavia. These remained intact because they were shielded by mountains. We can only imagine what the world would be like today if this were still land.

The reason this happened is that Europe does not have a Canadian Shield like Canada does. This underlying layer of rock prevented the glaciers from carving the land away during the ice ages. There is a large area of northern Canada that is not covered by the shield. This was also once land, but has been carved away by glaciers into a shallow sea, in the same way as the former northwestern Europe. This area is known today as Hudson Bay. If not for the Canadian Shield, this is what would have happened to virtually all of eastern Canada.

It is so named because it's shape resembles a shield, but the Canadian Shield truly is a shield in every sense of the word. Canada's national anthem refers to "standing on guard" for the country, and there is nothing that this better refers to than the Canadian Shield.

Sea Level During The Ice Ages

One thing that does not get discussed very much, but must have had a profound effect on the world that we have today, is the effect of the ice ages on sea level. Consider the following facts: The earth's surface is about 72% water. Glacial ice during the ice ages might have been 2-3 kilometers in thickness. The northern ice cap covers about 10% of the earth's surface today, but that increases to about 30% during the ice ages.

This can only mean that there must have been a drastic drop in worldwide sea levels during the ice ages of from maybe two hundred to five hundred meters. Shallow seas and continental shelves all over the world became dry land.

There is one really curious thing about the extent of glaciation during the ice ages. Almost all major glaciation on land during these times occurs in the northern hemisphere. Even though Antarctica is supposedly the coldest place on earth, there seems to be little of the glacial effects on Australia and southern Africa that can be seen all over North America and Europe. There are some glacial effects on the east coast of Australia, for example, but these are from locally-produced mountain glaciers.

I find that this fact reveals a lot about what goes on in the oceans during the ice ages.

My belief is that glaciers moving to lower latitudes from the polar regions during ice ages can only cross land, not deep water, or they would start to melt. Wide stretches of deep ocean is why Antarctic glaciers do not reshape southern lands in the same way as happens in the north. The ocean between Antarctica and other southern continents is simply too deep to be transformed into land by the water redistribution so that glaciers can cross.

This must mean that the shallow water all around northern Europe becomes land during ice ages. On a physical map of the area, it is easy to see the deep underwater trench all around the southern part of Norway, carved by the movement of vast icebergs. This raises the question of what effect this has on living things in these shallow waters in high latitudes. There seems to be little documentation concerning this question that I can find.

I reason that there must have been a mass exodus of fish and other marine life away from these shallow northern seas that cease to be to the deeper water that remains ocean. But deeper water and shallow water are altogether different environments for marine life. The edible plants at the base of the food chain grow on the sea floor and so are much more accessible in shallow seas. There is practically no plant life below about 180 meters depth because the sunlight on which plants depend cannot penetrate any deeper.

This can only mean that large fish populations in shallow water simply do not survive the move to deeper water that does not become land during the ice ages. We do know that the reason there is a wider variety of plants in North America than there is in northern Europe is because when the glaciers moved southward, some species of plant were blocked from retreating southward by the Alps Mountains. My hypothesis is that marine life must have been affected in a similar way but I can find little writing about this.

Another effect that the removing of shallow seas during the ice ages would have had is to increase the salinity of nearby deeper water that remained ocean. This is because the salt would become more concentrated. This must also have had an effect on life in the sea that I cannot find documented.

Another factor that may have contributed to bringing the ice ages to an end is the effect of the much lower sea level on the precipitation that is necessary to maintain glaciers. Some glacial ice is always melting, but is replaced by more falling snow which gets compressed into ice. If the surface area of the world's oceans is vastly reduced by this redistribution of water then that must mean much less water evaporating to eventually fall as snow to replenish the glaciers.

It might also seem that, since the oceans absorb a lot of carbon dioxide which is a greenhouse gas, with less ocean surface there would be more CO2 in the air to warm the planet and end the ice age. While this may be a factor also, this lack of absorption would be at least partially made up for by the growth of land plants, and their absorption of CO2, on dry areas of former sea bed. There must have been trees and plants and animals on vast areas of land that have since returned to the sea.

Have you ever wondered how people in prehistoric times got to all of the places on earth that they did, without sea-worthy ships? If the sea level of the world's oceans underwent this drastic drop, many isolated lands would then become accessible.

Asians could walk from Siberia to Alaska to populate the western hemisphere and become the native Indians, from the Eskimos to the Inca, over time. Other Asians could walk to Japan and settle there before they were once again cut off by the rising waters at the end of the ice age. Britain and Ireland were a part of Europe without the North or Baltic Seas. One could easily walk from India to Sri Lanka, or across the dry seabed of what is now the Persian Gulf. Prehistoric Greeks could walk to any of the Aegean islands. Italy was joined to Europe to the east over a dry Adriatic Sea. Florida and Mexico's Yucutan Peninsula had much more land than they do today.

Other formerly isolated lands were, if not directly connected by dry land, were brought close enough to settled lands to be crossed by people on primitive rafts or floating logs. This is how Aboriginals got to Australia when the Sunda and Arfura shelves became dry land, joining the islands of Indonesia together and bringing an expanded Australia within rafting distance.

This explains why no prehistoric people ever reached Iceland. It has no original inhabitants, but only the descendents of much later European settlers. It is because the waters around Iceland are deep.

There were migrations of animals also, but this is not the same thing as what I will call "Hemisphere Pairing". The eastern and western hemispheres were once together geologically, and we can see this in the similarities in some animal species which developed separately after the tectonic split.

There is a lot of similarities between camels on one side of the world, and llamas in South America. There are lions in Africa, and cougars in North America. Likewise, there are leopards and cheetahs in Africa and related jaguar in South America. There are monkeys in both hemispheres, but only those in the western hemisphere can grasp with their tails. The reason that wolves are found in both hemispheres is that they can withstand the cold enough to journey from Siberia to Alaska.

The last ice age ended in prehistoric times, about 12,000 years ago. But we can see how it has influenced human civilization. Civilization began in the Middle East and to some extent in the Far East. Notice that the Middle East is mostly desert, which is relatively free of disease in comparison with jungle, and also far enough south to be away from most of the glaciation during the ice age. I do not believe this to be coincidence.

New York's New Finger Lake

Letchworth State Park, in western New York State to the southwest of Rochester, hosts what is referred to as "The Grand Canyon of the East". This canyon, and the sorrounding green of the park, can be easily seen on the satellite imagery of http://www.maps.google.com/ .

The Genesee River flows northward through the canyon and over several waterfalls, including one that is higher than Niagara Falls. So, this canyon inevitably gets compared to the gorge at Niagara and is presumed to have been formed in a similar way to this and the Grand Canyon in Arizona, which was carved out of the layers of sandstone by the Colorado River.

Today, I would like to introduce another point of view on the formation of the canyon at Letchworth State Park.

The canyon is actually one of the Finger Lakes of central New York State. But due to the elevation and slope of the land, the canyon is not filled with water like the Finger Lakes to the east, but rather a river runs through it.

These deep and elongated lakes were carved out of the rock by glacial movement from the north during the ice ages. The area must have been the site of very concentrated glacial activity because of the presence of the Niagara Escarpment to the west and the Adirondack Mountains to the east. These two permanent features acted as the sides of a "funnel" to channel a powerful glacial movement across the area where the Finger Lakes are located.

Just look on the map at the location and directional alignment of the canyon at Letchworth State Park, relative to the Finger Lakes located just to the east. The canyon fits right into the pattern of these lakes, and I am certain that it was formed in the same way rather than being carved by the river that flows through it. There was a glacial thrust channeled by the Niagara Escarpment, and going somewhat behind it, that carved this canyon out of the rock over successive ice ages and also the smaller Silver Lake to the west. The Genesee River found it's way into the canyon later.

At Niagara Falls, there is a valley in the rock layers which guided the flowing water to form the falls and the gorge, this is the valley that I named "The Niagara Valley" and is described in the posting on the Niagara natural history blog by that name. But at Letchworth, there is no such valley to guide the river which supposedly carved the canyon over time.

I usually do not like the word "impossible", so let's just say that it is extremely unlikely that the flowing waters of the Genesee River carved this canyon out of the rock at Letchworth, as is commonly believed. For one thing, water is not neat when it carves it's way through soil or limestone. Neither the Grand Canyon nor the Niagara Gorge are anything like neatly carved. But look at some of the photos on the article titled "Letchworth State Park" on http://www.wikipedia.org/ . In one photo, the rock wall of the canyon is so neatly cut that it looks like a cake cut by a knife. Ice is much neater than flowing water, and that is definitely the work of ice and not water.

You can see in the satellite imagery that the river actually meanders from one side of the canyon to the other, and that would not be the case if the river had carved the canyon.

Consider the sheer volume of water that carved the Niagara Gorge. The flow of water through Niagara is probably a thousand times that of the Genesee River, which supposedly carved this Letchworth Canyon. It is true that there was a lot of water around when the glaciers melted at the end of the ice ages, but that water supply lasted for only a brief time. There are other features around Rochester that were shaped by this rush of glacial meltwater, described in "Water Inlets Of The Niagara Escarpment Bulge" on this blog, but there is nothing anywhere else in the area like this canyon.

I think that we can safely consider the canyon at Letchworth State Park to actually be one of the Finger Lakes except that, due to the slope and altitude of the terrain, it is not filled with water like the other Finger Lakes, but rather a river runs through it.

Lake Chautauqua And The Niagara Escarpment

I have noticed a relationship between the Niagara Escarpment and Lake Chautauqua that I cannot find has been pointed out before. This relationship does a lot to illustrate how the movement of ice age glaciers is affected by obstacles such as an escarpment. As always when I write about geology and natural history in the general area where I live, I try to write in such a way that the reader will not need to be familiar with the area to understand it.

Here is a map link, or you can use an atlas: www.maps.google.com

If you do happen to be familiar with the western New York State area, your first reaction might be to wonder what picturesque Lake Chautauqua, in the southeast corner of the state, could possibly have to do with the Niagara Escarpment, which is nearly a two hour drive away. To see what the two have to do with each other, the lake is actually a creation of the escarpment, let's look at a map showing all of the escarpment.

The Niagara Escarpment is a very prominent feature of the landscape which can easily be seen on any map of the northeastern U.S. Start with the Door Peninsula, which separates Green Bay in Wisconsin from Lake Michigan. This peninsula is part of an arc that continues across northern Michigan to Manitoulin Island, which separates Georgian Bay from Lake Huron, to the Bruce Peninsula of Ontario.

The escarpment continues southward across southern Ontario until it changes direction at Hamilton. From there, it continues eastward to Rochester where it terminates. Three cities; Hamilton, St. Catharines and, Lockport, NY are built right on the Niagara Escarpment, with part of the city on the higher level and the rest below the escarpment.

I have written extensively about the escarpment in numerous postings on the geology, glacial and, Niagara natural history blogs. The posting "The Niagara Escarpment And The Meteor", on the geology blog www.markmeekearth.blogspot.com , explains my theory of the origin of the escarpment. It is not a fault line as it may appear but the result of uneven erosion of the limestone layers over millions of years. "America's Escarpment State", on this blog, explains how the upper Great Lakes were shaped by the interaction of glacial ice with the escarpment.

The escarpment is not simply a higher level above a lower level. It is actually in the form of a sawtooth, with the upper level gradually getting lower in elevation as we move away from the brink of the escarpment.

There are many elongated lakes in western New York State, carved by the movement of glacial ice during the ice ages. The well-known and scenic Finger Lakes can be easily explained by looking at the map. We know that the Niagara Escarpment ends at Rochester and that there are the Adirondack Mountains in the eastern part of the state. These two barriers had the effect of a funnel in that they concentrated the movement of ice into the space between them.

This especially heavy concentration of glacial ice carved the Finger Lakes. In fact in the posting on this blog, "New York's New Finger Lake" I explained my reasons for believing that the gorge at Letchworth State Park was actually formed as one of the Finger Lakes.

The thing that is puzzling about Lake Chautauqua is it's directional alignment, which is from northwest to southeast, so that it does not match the alignment of any of the other lakes at all. It is deep and narrow lake, typical of those carved by glacial ice, and is actually a double lake with two basins.

It is not difficult to see how the lake was formed, there is a broad rounded ridge between it and Lake Erie with Westfield on one side and Mayville on the other side. Ice coming down over that ridge, which was formed by the tectonic collision which formed the Appalachians, carved the lake.

Now, let's go back to the Niagara Escarpment. My hypothesis is that, while the outside of the escarpment formed a natural barrier for ice, glacial ice was also guided along the inside of the escarpment since it is shaped like a sawtooth. Follow the curve of the escarpment on a map across northern Michigan, which is actually a creation of the escarpment, along Manitoulin Island and the Bruce Peninsula in Ontario.

But then, while we know that the escarpment changes direction at Hamilton, continue the same line across southern Ontario and Lake Erie. Notice that this curve, if continued, brings us right to Lake Chautauqua and in the exact directional alignment of the lake.

This solves the mystery of how the lake came to be, glacial ice was guided by the inside of the Niagara Escarpment and pulled by the rotation of the earth to the south and east, and carved the lake as it came over the broad, rounded ridge between Lake Chautauqua and Lake Erie.

Let's call this movement of ice the Chautauqua Movement. The term "chautauqua" is actually a part of American history. In the days before radio and television, tents would be set up to bring various educational lectures and arts to rural areas with the same concept as a travelling circus. The original chautauqua was on the shore of the lake and is now known as the Chautauqua Institution. But that version of chautauqua has long since passed so that it can now be the name of this glacial ice movement along the inside of the Niagara Escarpment.

There is yet another example of a lake with a mysterious directional alignment in western New York State. This one is known as Waterport Pond, or Waterport Reservoir. It is much smaller than Lake Chautauqua and is found north of the Niagara Escarpment in Orleans County, between the towns of Medina and Albion and not far from the shore of Lake Ontario. This is also an elongated lake, but it's directional alignment is actually perpendicular to the usual glacial movement from the north northwest.

The reason for the formation of this lake is ice being deflected off a limited area of the escarpment. In the same way that a ball thrown at a wall, but at a certain angle, will bounce off the wall at the same angle but on the opposite side.

The Cross Creek Hypothesis

I would like to describe a land form that I have noticed but cannot find documented anywhere. Simple logic dictates that when there is a gradual slope to underlying rock strata, a flow of water on the land above will flow along the slope of the rock strata and thus the land. However, there are a number of creeks (brooks or streams) in areas that were once covered by glaciers that flow not along the direction of slope to the land but across it.

In the Niagara Falls, NY area, there are two such examples of "cross creeks", as I will call them. Here is a map link with satellite imagery if you want to have a look http://www.maps.google.com/

One is Bergholz Creek in Niagara County, within the city limits of Niagara Falls, it is known as Black Creek. From Lockport Road, it is easy to see the southward slope of the land while looking across the farms to the Village of Bergholz. So why then does Bergholz Creek flow more westward, rather than southward?

Ellicott Creek in nearby Tonawanda also follows exactly the same pattern. We can see that south of the creek in the City of Tonawanda the ground is actually subtly sloping downward going south away from the creek. At first glance, this seems to make no sense. Why does the creek flow westward while the slope of the land is primarily southward?

To explain the flow of these two creeks, let me now describe the formation of a cross creek. At the end of the last ice age, about 12,000 years ago, the glacier began to melt and break apart as the climate became warmer. In places where there was some slope to the land, as in the Niagara Falls area, massive bergs of ice slid across the slope of the underlying rock strata, plowing up the ground in front of them until they melted enough to come to a halt.

At the edge of the melting berg, a flow forms from the meltwater but because of the furrow in the ground that the berg has plowed, the water flows across, rather than along, the primary slope of the land and a cross creek is born. A cross creek usually joins a larger creek that is not a cross creek.

In Niagara Falls, neither Cayuga Creek, which Bergholz Creek joins, nor Gill Creek are cross creeks. I decided not to classify Tonawanda Creek as a cross creek because I believe it to have been the primary drainage channel of the eastward portions of the fomer Lake Tonawanda that covered much of the area after the end of the last ice age.

Cross creeks require sliding bergs of ice to form and may have acquired seemingly illogical bends or turns. Both Bergholz and Ellicott Creeks make northward bends, against the underlying slope of the land, before joining larger creeks.

The Next Ice Age

There have been more than twenty known ice ages in the history of our planet and much has been written about their effects that we can see today. But have you ever wondered what changes to the present geography of earth the next ice age will bring? To explore this question we must, of course, put global warming aside for the moment and assume that there will be another ice age in the future.

Basically, the continents and islands of the world are built up by tectonic collisions and volcanic activity which is then shaped by primary and secondary glaciation during the ice ages. A glacier that advances southward during ice ages is a mountain of ice maybe two km thick that spans an area hundreds of kilometers wide. As I have pointed out in my discussions of glaciation, much of the lasting effect on the landscape of glaciers is from secondary, rather than primary, glaciation. That is at the end of ice ages as the climate warms, massive bergs of ice break off the melting glacier and impact and slide over the land below.

It is my feeling that the place which will be most affected by the next ice age will be Europe. On http://www.maps.google.com/ we can see the vast shallow area of water around northwestern Europe. It is also easy to see how the continents have split apart due to the volcanic spreading of the Mid-Atlantic Ridge. This vast wedge-shaped area of shallow water can be seen to have split off the area of continental shelf around Newfoundland in eastern Canada.

This area of shallow water in northwestern Europe was almost certainly once all land which has been eroded away to below the water level by glaciers in successive ice ages. This includes the North, Baltic and, Irish Seas also the English Channel and far out into the Atlantic Ocean. You can see a shallow area to the northwest of Ireland and about the size of that country. This must have once been an island about the size of Ireland that is now gone. Denmark is all lowland that would have been eroded away by glaciers except that it was shielded by the bulk of the Norwegian Mountains.

There are two significant curves that we can see on the map of western Europe where glaciers have carved away at the land in ice age after ice age. the west coast of France along the Bay of Biscay has been gradually carved away although it has been shielded by the mountains on the peninsula known as Brittany. The other curve is from the northwest corner of the Netherlands to Calais at the Strait of Dover. We can expect that the next ice age will continue this process.

In my posting, "New Discoveries In Northern Europe" on this blog, I explained why Britain must have had ice crossing it from both the northwest, where it would usually come from, and also the northeast, due to ice piling up against and being deflected by the Norwegian Mountains. The ice from the northwest should be far greater in volume but it actually is not, because Britain is in the "glacial shadow" of Iceland.

The main route across England of the ice that comes from the northwest during ice ages is through the North Channel, which separates Scotland from Northern Ireland. The main route of ice then follows what I will call the "Severn Route". There is are two bays just southwest of Liverpool with Birkenhead between them. This represents the crossing of the main bulk of glacial ice onto land from the shallow sea, which freezes during the ice ages.

The ice goes around the Welsh mountains and is diverted southward by the southern portion of the Pennine Mountains. The ice continues southward through what is now called the "Severn Vale" and is occupied by the present-day Severn River. The flow of ice continues to the Bristol Channel.

The mountains of Wales are the primary factor preventing the ice from taking a more direct route southward. The Severn Vale is much too vast to have been carved by water alone and there is no evidence that it is a fissure in the earth's crust or anything like that. Furthermore, I have shown in my posting "New Discoveries In The Forest Of Dean" on this blog that the ice from the Vale produced a glacial impact crater at Cinderford.

My hypothesis is that the Severn Vale has not yet been eroded enough by the ice in ice ages to be below water but that may well change with the next ice age. Wales will become an island at that time and there will be a channel of the sea from what is now Liverpool to Bristol.

The only reason that this has not yet happened, that the Severn Vale is still dry land is the Isle of Man. The main thrust of the glacial ice comes through the break in the mountains and high ground that is the North Channel. But instead of going straight toward Liverpool, the majority of the ice is diverted southward by the mountainous Isle of Man.

Only a portion of the main glacial thrust goes around the Isle to the north and goes through the Severn Route. Liverpool and the Severn Vale are in the glacial shadow of the Isle of Man just as all of Britain is in the glacial shadow of Iceland.

The Isle of Man itself is being eroded away by glaciation in successive ice ages. When it is gone, the main thrust of ice will go through what then may be called the "Severn Channel" and it will get wider and wider. Eventually Wales, as seen from England, will be but a line of mountains on the horizon.

The Carmarthen Raceway

I notice that there is a valley in south Wales that has had a very important role in shaping the coastal topography of the southwestern part of the country. I did a survey of the landscape of Wales using http://www.maps.google.com/ as well as the more advanced Google Earth, which is not free on the internet. This valley extends from the town of Carmarthen northeastward to Builth Wells. In surveying the valley using Google Earth, I started in Builth Wells and found my way to Carmarthen by following the area on the screen lowest in elevation above sea level.

The great effect that this valley must have had on the Welsh coast centers around what happens at the end of each of the successive ice ages. As the climate gets warmer, the glacial ice in the warmer lowlands will melt first. As the ice in the mountains begins to melt and break apart into large bergs, it slides along valleys such as this, which I have termed "The Carmarthen Raceway", on the way to the sea. As it does, it reshapes the coastline.

Ice usually covers about 10% of the earth's surface but during ice ages, that increases to maybe 30%. There is known to have been more than twenty such ice ages.

(Note to readers- In this posting I have attempted, as far as is possible, to select landmarks that have English, rather than Welsh, names. Cities tend to have English names but many towns and villages in Wales have Welsh names. This is not intended as an affront to Wales, which is a fabulous and scenic place, but only for the ease of my readers. Welsh names are not pronounced as they appear in English and three Welsh letters are not used in the English language and are written in Welsh as doubles- FF, LL and, DD.)

Carmarthen Bay on the south coast of Wales was dug by ice moving through the Carmarthen Raceway at the end of each ice age. Using the satellite imagery on http://www.maps.google.com/ you can easily see how cliffs alternate with beach around the coast of Carmarthen Bay, the shadows of the cliffs can be seen. This is because, ice from the Raceway will carve away the cliffs to form a low area and then moving ice from successive ice ages will follow the same low path. This leaves cliffs intact in some places but erases the cliffs to form beach in others.

Notice how there is much more sand, including the vast Pendine Sands, on the eastern side of Carmarthen Bay. This is simply because of the northeastward direction of the waves from the ocean.

There is much more cliff that has survived the ice ages around Saundersfoot on the western shore of the bay because that was more in line with the direction from which ice came from the Carmarthen Raceway. At the holiday town of Tenby, at the southwestern corner of Carmarthen Bay, there is an extensive stretch of beach facing east but a short distance away, there is no beach facing south. This plainly illustrates how the moving ice removes cliffs to form beaches and the direction of the Carmarthen Raceway from which it came.

Notice the two small islands just off Tenby that are islands at high tide but not at low tide. It is obvious that these satellite images were taken at low tide because many small boats can be seen on the sand at Saundersfoot and Tenby.

From high up, you can see that there are two long stretches of wide beach that are parallel to each other, along the same axis. One is at Tenby and the other is from Saundersfoot to Amroth. These point along the main direction of the moving ice and point directly at the Carmarthen Raceway.

Caldey Island, the large island south of Tenby, was cut away from the mainland by the ice over successive ice ages. From above, it is easy to see how the island is gradually being cut up by the ice. The buildings on the island are a Cistercian monastery. (I believe it is also spelled "Caldy" but on the map it is mispelled "Caldney")

I notice many of what I will call "gorges" on the southwestern coast of Wales. I call them this because they remind me of miniature versions of the one at Niagara Falls. There are three of them in a row on the coast south of Buckspool, west of Tenby. I am certain that these gorges are the first step in the destruction of a stretch of cliff to form a beach. Gorges are narrow while beaches are wide. They are most likely formed by flowing meltwater from glaciers that forms a waterfall over the cliff and erodes it's way backward.

Moving westward, the city of Milford Haven lies in a low area near the coast with a river. This is actually the deepest waterway in Europe and was obviously carved out by moving ice. Remember that bodies of water dug by glaciers tend to be either broad and shallow or narrow and deep.

The form of the coast around the inlet to Milford Haven is similar to that of southwest Ireland and was formed in the same way. It is easy to see the path of the ice here at Sandy Haven, west of Milford Haven, and by the extensive beach at Castlemartin nearby.

In my estimation, there are three main tracks that the ice from the Carmarthen Raceway follows on it's way to the sea at the end of each ice age. The first is that which formed Carmarthen Bay. The second is that which dug the waterway at Milford Haven. The third is the one which created St. Bride's Bay to the north of Milford Haven.

At the southwestern corner of St. Bride's Bay there is very rugged rock that has resisted the ice while being "polished" by it. You can see how Skomer and Skokholm Islands were cut away from the mainland by the ice, just as Caldey Island was. Notice how the southward shore of Skomer Island is much more rugged than it's northern shore because this is the direction in which the ice was moving.

The thing that is so interesting about St. Bride's Bay is that wide beaches are to be found only on it's eastern shore because this is the direction from which the ice came. The eastern shore, in sharp contrast to the other shores, is more beach than cliff. There are relatively few cliffs there, such as the one at Broadhaven.

Another point of interest concerning St. Bride's Bay is that there are many narrow gorges on it's northern shore but none on it's southern shore. The ones on the northern shore all point to the southwest, the direction in which the ice was moving from the Carmarthen Raceway.

Waves from the ocean are certainly also a factor in the erosion and shaping of coastlines such as this, but by far the main factor was this ice. There are many videos on http://www.youtube.com/ of this area of the Pembrokeshire coast so you can see up close what it looks like.

In my survey of the Welsh coast, I notice that the west coast of Wales gets smoother as we go north. This is because it was away from the ice flow of the Carmarthen Raceway. The coast gets noticably smoother north of New Quay and smoother still north of Aberystwyth (This is the Welsh name of Wales' most important west coast city but English people say it the way it looks in English, although this pronounciation is not technically correct.) However, north of Caernarvon Bay to Holyhead the coast becomes rugged again. Anglesey clearly displays the southwest to northeast lines of primary glacial movement from beyond the shield provided by the mountains of Wales.

Going back to south Wales, you will notice another bay to the west of Carmarthen Bay by the name of Swansea Bay near the city of that name. This bay was formed in exactly the same way as Carmarthen and St. Brides Bays. There is a valley northward from this bay up to Brecon Beacons through which flows the Neath River. This valley operated as a raceway for the ice in the same way as the Carmarthen Raceway.

Far to the north on the west coast of England is the large Morecambe Bay. This was also formed by bergs of ice at the end of ice ages flowing through a nearby valley after coming down from mountains. In surveying Morecambe Bay by the satellite imagery, it does not seem to have the cliffs around it that the Welsh bays do and this made the erosion faster and more extensive to form a larger bay.

On the far western tip of France we find the same type of phenomenon. I did a survey of this area and there is the same alternation of cliffs and beaches. Notice that Baie de Douamenez and the nearby waterway at the city of Brest is very similar to St. Brides Bay and the nearby waterway at Milford Haven. The main difference is that in Wales, the bay is to the north of the glacial waterway while in France it is to the south.

The Story Of The Forest Of Dean Area

There have been two parts to the posting "New Discoveries In The Forest Of Dean". Recently, I became aware of a project to extensively photograph every corner of Britain and Ireland and post the tens of thousands of photos. The site of this project is http://www.geograph.org.uk/. I have found the photos on the site to be immeasurably helpful in the study of natural history and I have decided to supplant the previous postings with this one, with links to photos included.

Here are map links. If you wish to follow along on a map, just enter in Lydbrook to start. http://www.maps.google.com/ and http://www.multimap.com/ The Forest of Dean is the western portion of Gloucestershire in England, along the border with Wales. Much of what we will be discussing is in the neighboring county of Herefordshire.

By the way, both of these map sites offer a download to make the map three-dimensional and I would like to assure readers that both downloads are perfectly safe.

I am so interested in the Forest of Dean simply because Lydbrook was where I entered the world. In terms of physical geography, the northern section of the forest is high ground divided up by several valleys. The hills representing the high ground are not material deposited by glaciers. Rather, the layers of rock representing the high ground are being cut up by glacial movement during the ice ages, leaving the valleys.

The high ground in the Forest of Dean could well have been land forced upward during the continental collision that I described in the posting "The Mysterious Geography Of Britain" earlier in this blog.

The wonderful thing about these photos is that they enable all readers, even the vast majority which would not be familiar with this area, to see how glaciers interact with land during ice ages. Similar examples can be found all over the approximately 30% of the world that was then covered by glaciers. The activity of glaciers in the Forest of Dean involves both primary glaciation, the movement of glaciers at the beginning of ice ages and secondary glaciation, the effects on the land when glaciers melt and break up at the end of an ice age.

There have been more than twenty ice ages. The last one began about 20,000 years ago and ended about 12,000 years ago.

SYMONDS YAT

Let's start our exploration of the Forest of Dean at a place called Symonds Yat. There are two slices into the rocky high ground here, which were created by the glaciers coming down from the Welsh Mountains during the ice ages. The glaciers which passed over the forest probably originated in the low area northwest of the city of Hereford, around Weobley and Kington, which is sorrounded on three sides by mountains. As I have documented on my geology blog, http://www.markmeekearth.blogspot.com/ glacial ice actually moves toward the southeast, rather than due south, because the eastward rotation of the earth imparts momentum to it.

It is very important to realize that it was not the main force of the glaciers which passed over the forest during the ice ages, but the somewhat lesser glaciers which came down out of the mountains. If it had been the main force of the glacier it is possible that all of the high ground in the Forest of Dean would be gone by now, but the Welsh Mountains formed a shield.

The main thrust of the glaciers from the northwest went between the gap between the Welsh Mountains and the Pennines at Liverpool. The glaciers carved away the ground as they proceeded along this route and the result is the Severn Vale. This is the broad low area around the Severn River. The Forest of Dean is on one side of the Severn Vale. The ice which passed over the forest joined the main flow of ice here.

Overlooking the village of Symonds Yat is the observation point on Yat Rock. If we look northwest from there, this is what we see:

www.geograph.org.uk/photo/784049
www.geograph.org.uk/photo/1117516

Notice the Welsh Mountains in the distance, and the lowland in between. This is from where the glaciers came www.geograph.org.uk/photo/530746

We are looking northwest in these photos. The valley is the Wye Valley, named for the river which flows through it. The Wye flows southward from here and joins the Severn River at Chepstow.

In no way did this river carve the valleys through which it flows, the glaciers carved the valleys and the flow of the river found it's way through after the last ice age. The large loop in the Wye River on opposite sides of Yat Rock through Huntsham demonstrate how fast the water must have been flowing at the end of the ice age. It required this wide loop to make the 180 degree change of direction.

The formation of valleys like these through layers of rock do not necessarily happen during one ice age. A flow of water, whether from a permanent river or a flow of meltwater at the end of an ice age, will weaken the rock beneath it. Then when the next ice age arrives, the ice can push it's way into the weakened rock and the process is repeated over successive ice ages, until we have the finished valley.

Now let's look in the other direction from the top of Yat Rock, to the northeast: www.geograph.org.uk/photo/1617787

The elongated hill on the right is known as Coppet Hill (I have seen it spelled in different ways). Coppet Hill is aligned at a moderate angle to the direction of glacial movement from the northwest. The result is that it deflected the oncoming ice so that it broke through the limestone to the east side (right) of Yat Rock.

The elongated Coppet Hill also acted as a barrier so that it created a "glacial vacuum" behind it. Further east, the ice broke through the rock at yet another point at Kerne Bridge. The ice that came through there was diverted by the ice piled up against Ruardean Hill so that it was diverted into the "glacial vacuum" behind Coppet Hill.

This movement of ice eventually met that which had cut into the rock at the east side of Yat Rock. The result as seen today is the semi-circular valley around Coppet Hill and the area to the east of it, up to Kerne Bridge.

Here is the view, looking north, from the top of Coppet Hill. You can see the Kerne Bridge, over the Wye River, and Leys Hill on the other side of it. After Leys Hill, there is Chase Hill. The valley between Leys Hill and Chase Hill is at Coughton, which we will get to later. On the other side of Chase Hill is the town of Ross-on-Wye, which also has a valley that we will see. www.geograph.org.uk/photo/1187565

Here is a view of Coppet Hill from Leys Hill, to the east. The valley and the Wye River is between the hills: www.geograph.org.uk/photo/1309557

In this view, the mountains from where the glaciers came are in the distance. Coppet Hill is closer and the Wye River is in a hidden valley, carved by the glacier, before Coppet Hill: www.geograph.org.uk/photo/119223

Here is a view of the mountains in the distance from Ruardean, on Ruardean Hill south of Leys Hill: www.geograph.org.uk/photo/119217 A lot of glacial ice was pressed against Ruardean Hill during ice ages and when it melted, it formed Lodgegrove Brook, which runs east-west just north of Ruardean Hill.

LYDBROOK

Now, let's consider the long valley which extends southward from the village of Lydbrook. In fact, Lydbrook is built along the road along the bottom of the valley.

The two channels of ice described above, one beginning to the east of Yat Rock and the other beginning at Kerne Bridge, cutting their way through the rock, met at what is now the bottom of Lydbrook, where the Wye River now flows. The two channels of ice collided and diverted one another southward, cutting the valley through Lydbrook.

The peaceful serenity of Lydbrook along the Wye today belies the violence of the ice collision which formed it, the same goes for Symonds Yat. If you wonder how moving ice can cut such relatively neat channels through rock the reason, once again, is that a flow of water in times past will weaken the rock so that moving ice during a subsequent ice age will find the weak spots in the rock and force it's way through.

The valley through Lydbrook is dry today, but at the end of the ice ages it was a raging river of water from the melting glacier atop the area. It extends along New Road through Parkend and onward to the Severn. There are a number of entrances through which meltwater flowed into the Lydbrook Valley which are readily visible today. One is the valley around Speech House Road just east of Mile End and Broadwell, near Coleford. Deeper in the forest, water running into the Lydbrook Valley long ago formed a canyon at Wimberry Slade. There are more such channels to be seen on an ordnance map of the forest.

Here is where this great collision of ice took place at the bottom of Lydbrook, where the Wye River flows today: www.geograph.org.uk/photo/523362

This is another view of the Wye Valley, where the collision took place: www.geograph.org.uk/photo/1427622

These are views across the valley through Lydbrook. These are closest to the Wye River and the collision which diverted both channels of ice southward to form the Lydbrook Valley: www.geograph.org.uk/photo/1427688

www.geograph.org.uk/photo/133146

www.geograph.org.uk/photo/454739

Here is the valley through Lydbrook a bit further away from the Wye River, which is where the ice collision took place:

www.geograph.org.uk/photo/133140

www.geograph.org.uk/photo/1045033

This photo is taken from across the Wye Valley from Lydbrook. You can see the Wye Valley in front of you and the Lydbrook Valley, with the houses in it, between the two hills in the distance. This makes it easier to imagine how the two channels of ice collided while forming the Wye Valley and, diverting each other southward, formed the Lydbrook Valley: www.geograph.org.uk/photo/355420

This valley continues southward to Parkend: www.geograph.org.uk/photo/1319028 and Lydney.

BICKNOR

The collision between channels of glacial ice in what is now the Wye Valley, and which diverted each other's force southward to cut the Lydbrook Valley, was not quite so neat and simple. The proportion of ice coming through each end varied. For a time, the ice of the combined channel actually went in a different direction, and not through the Lydbrook Valley.

In the photo above, the ice also formed a much smaller and incomplete valley to the right (west) of the Lydbrook Valley. This is what we could call the Bicknor Valley because it is near the village of that name.

By the way, there is two villages named Bicknor. One is Welsh Bicknor, and the other is English Bicknor. Here, I am referring to English Bicknor. Welsh Bicknor is across the Wye River from Lydbrook. Both of these villages are actually in England. The reason that they are so-named is that a lot of Welsh Labourers (laborers) lived in one of the villages, so it became known as Welsh Bicknor.

Here are some photos of the valley at Bicknor. It forms a V with the origin of the Lydbrook Valley, pointing at their common origin. A small brook now flows through this valley. The Bicknor Valley was never completed down to the Severn Vale and it shows what the Lydbrook Valley must have looked like at an earlier stage of it's development:

www.geograph.org.uk/photo/454777

www.geograph.org.uk/photo/575830

www.geograph.org.uk/photo/454785

www.geograph.org.uk/photo/1543848

www.geograph.org.uk/photo/454791

www.geograph.org.uk/photo/73772

www.geograph.org.uk/photo/890991

By the way, look at how rounded are the Welsh Mountains in the distance. That means that the mountains are very old. One of my theories is that these mountains were once high enough to block the weather and that is why there is so much coal in Wales today. You can see "Coal Made Really Simple" on my geology blog.

THE WYE VALLEY

Let's go back to the scene at Symonds Yat: www.geograph.org.uk/photo/784049 and consider the Wye Valley from this point southward, until it joins the Severn River.

There are two places in this stretch of the Wye Valley where a branch river formerly joined the main river until changes in water flow after the end of the ice age caused the upstream section of the main river to either run dry or to become a very minor flow and the former branch to become the main river.

The first such instance is at Garnew, west of Symonds Yat. The former upstream of the river is completely dry and what was once merely a branch flowing into the main river has become that river.

The second is at Monmouth. The Monnow River was once the main river. It was a glacial route from just north of the Black Mountains.

At Redbrook, we have an example of a dead end glacial channel off the main Wye Valley. The ice cutting this channel turned around and headed back northward.

The ice covering the area around Coleford was maybe one or two kilometres thick and when it melted, it released a temendous amount of water. This meltwater carved drainage channels in the rock as it made it's way to the Wye Valley, which we can see today.

Two obvious drainage channels are at St. Briavels and Bigsweir. Two drainage channels nearly opposite each other at Brockweir and Tintern created an opposing flow, forming the loop in the Wye River that is there today.

The Coleford area was a basin of water collection. A large drainage river flowed from here to Newland. The basin at Coleford also drained into the Lydbrook Valley through what is now the valley around Speech House Road. From the woods to the north of Staunton, I see that two gorges have formed as channels by which meltwater flowed into the Wye Valley.

Look at the basin that Coleford is built in and the slopes of the basin within the town: www.geograph.org.uk/photo/765926

www.geograph.org.uk/photo/765947

www.geograph.org.uk/photo/766954

www.geograph.org.uk/photo/842699

Here are scenes of the Wye Valley, and valleys that once drained water and ice into it, at various points from Symonds Yat southward to union with the Severn River. The first two photos are of former drainage valleys which emptied into the Wye Valley and, the rest are of the Wye Valley itself:

www.geograph.org.uk/photo/908491

www.geograph.org.uk/photo/520170

www.geograph.org.uk/photo/707629
www.geograph.org.uk/photo/474580
www.geograph.org.uk/photo/1786549
www.geograph.org.uk/photo/11219
www.geograph.org.uk/photo/1499407
www.geograph.org.uk/photo/1402615

ROSS-ON-WYE

Moving northward, there is another valley which served as a mighty river at the end of the ice ages to drain meltwater, but which is dry today. The valley through the town of Ross-on-Wye has similarities to the one through Lydbrook. It was formed when glacial ice found a weak spot in the rock from a previous flow of water over that rock. The glacier was probably also diverted by ice piled against Leys Hill and Chase Hill. If there were a source of water where the Severn Vale is now located, this would be a major river flowing through Mitcheldean and Longhope.

On a map or the satellite imagery, it is easy to see that there is a major bend in the Wye River at Ross-on-Wye. This is because we have a situation similar to that at Monmouth and Garnew. This valley through the town was actually the main river following the ice age and the flow from Hereford was only a branch joining it. But as the volume of water from melting glaciers reduced, this became a dry valley, as it is today.

The glacial thrust which formed the valley at Ross-on-Wye came north of Chase Hill and was then deflected southward toward Drybrook and Mitcheldean by May Hill, the route is now followed by Rudhall Brook. There is a nearby valley extending south from the village of Coughton from glacial thrusts between Howle Hill and Chase Hill and this glacial route in successive ice ages seems to join the one that went through Ross-on-Wye on it's way to Drybrook.

Remember the view from the top of Coppet Hill, looking eastward. You see a closer hill and a further hill. The valley at Coughton is between the two and the valley at Ross-on-Wye is on the other side of the further hill. The buildings of Ross-on-Wye are visible: www.geograph.org.uk/photo/1187565

Here is a view of Chase Hill from Bridstow, across the Wye River from Ross-on-Wye: www.geograph.org.uk/photo/996598

In this photo, the two hills which affected the flow of ice which formed the valley through Ross-on-Wye can be seen from Bridstow. Chase Hill is the closer one and May Hill, with the famous clump of trees on the top representing the highest elevation in the Forest of Dean, is the further hill: www.geograph.org.uk/photo/996593

Here are views in the valley at Coughton: www.geograph.org.uk/photo/1128524 www.geograph.org.uk/photo/478727

The photo web site does not have any useful views of the valley in the town of Ross-on-Wye, but if you would like to have a look at it, you can go to my photo blog of Europe. Just go down to the "Town of Ross-on-Wye" and you will see the slope of this glacial valley. http://www.markmeekphotos.blogspot.com/

So, the glacial valley through Ross-on-Wye starts as one valley before it splits. The valley through Lydbrook started as two valleys, but ended up as one. The Wye Valley, from Symonds Yat southward, is one throughout.

DRYBROOK

The glacial movement from Ross-on-Wye continues to Drybrook. The resulting Drybrook Valley is parallel to that of Lydbrook, it continues southward past Cinderford, through Soudley and ultimately, Blakeney into the Severn Vale. On the other side of Plump Hill from the Drybrook Valley are parallel drainage valleys through Mitcheldean and Longhope.

On my photo blog of Europe, http://www.markmeekphotos.blogspot.com/, the third photo from the top is taken in the direction in which the glaciers would have came to carve the Drybrook Valley. The photo is taken looking northwest and is the same photo on the cover of my book "The Theory Of Primes". Notice the U-shape to the ground that is characteristic of glacial movement.

Here are views of the Drybrook Valley:

www.geograph.org.uk/photo/1355250

www.geograph.org.uk/photo/119212

While driving through the area on the main road, the A4136, the valleys through Lydbrook and Drybrook can be seen as dips in the road level. Here is the one representing the Drybrook Valley at the Nailbridge traffic light: www.geograph.org.uk/photo/1124521

A similar dip can also be seen in the A4136 as one passes Lydbrook. I would like to point out that there is another dip in the A4136 at Brierley, between Lydbrook and Drybrook. This is yet another glacial valley similar to the other two, except that it is far less developed at this point. If there are further ice ages, there will be a valley at Brierley similar to Lydbrook or Drybrook. Here is the dip in the road at Brierley: www.geograph.org.uk/photo/555202

GLACIAL IMPACT CRATERS

Now, still at Drybrook, let's go on to another phenomenon. A glacial impact crater is a land form which I discovered and documented several in the area of Niagara Falls. They are described in detail on my Niagara blog.

Basically, a glacial impact crater is formed when glacial ice is pressed up against a hill or escarpment during an ice age. When the ice age ends, the ice begins to melt. The glacial ice might be one or two kilometers thick so that it will be warmer at the bottom than at the top. As the ice melts faster near the bottom, the glacier becomes top heavy and may also fracture laterally.

The result is a vast slab of ice weighing millions of tons falling from a height of a kilometer or more and leaving a very distinctive crater in the ground.

Not only is Drybrook a valley, it is also a glacial impact crater. During the last ice age, ice moving along the main glacial route through the Severn Vale pressed up against Plump Hill in Mitcheldean. When the ice age ended, such a vast slab of ice crashed into the ground near the Drybrook Valley.

The result is what we now call Harrow Hill. The hill slopes downward in the direction in which the slab was moving in the same way as all of the other glacial impact craters.

Here is a view from the top of Plump Hill, looking out over the Severn Vale: www.geograph.org.uk/photo/268007 Notice the drainage valley at Mitcheldean in the foreground, which I mentioned earlier.

Here are views of Plump Hill from below: www.geograph.org.uk/photo/739896

www.geograph.org.uk/photo/739886

www.geograph.org.uk/photo/535732

Look at the slope of Harrow Hill at Drybrook: www.geograph.org.uk/photo/1355254

www.geograph.org.uk/photo/587502

On my photo blog, I took two photos of Harrow Hill from across the Drybrook Valley at Ruardean Hill which clearly show the flat slope of the hill characteristic of glacial impact craters, they are the eighth and ninth photos from the top http://www.markmeekphotos.blogspot.com/

As such slabs of ice melt, they tend to leave culverts through which the water flowed away as the slab melted. Bridge Road on Harrow Hill is built in the low-lying culvert through which the meltwater drained away into the Drybrook Valley: www.geograph.org.uk/photo/1355263

CINDERFORD

Now that we are familiar with glacial impact craters, let's move on from Drybrook to Cinderford. The same process happened here. Ice from the main glacial route through the Severn Vale pressed up against Littledean Hill. At the end of the ice age, a vast slab of ice crashed to the ground on what is today the landscape of Cinderford. It is flattened and sloping, just as is Harrow Hill.

Here is the view from the top of Cinderford, looking east over the Severn Vale. The centre (center) of London is about 150 km in this direction. The high ground on the other side is the Cotswold Escarpment: www.geograph.org.uk/photo/1459070

Now if we go a short distance and look in the opposite direction, we find ourselves looking at the slope formed by the vast ice slab which crashed down: www.geograph.org.uk/photo/1459193

www.geograph.org.uk/photo/728707

www.geograph.org.uk/photo/1456369

www.geograph.org.uk/photo/728595

Here are other views of the slope of Cinderford created by the glacial impact crater, notice the similarity to Harrow Hill: www.geograph.org.uk/photo/1039189

www.geograph.org.uk/photo/728568

Cinderford actually has two slopes, another one sloping down off the one caused by the impact crater. The lower, secondary slope is actually the side of the Drybrook Valley through which torrents of water flowed at the end of the last ice age. You can see in this view that the Cinderford area actually forms a bowl with Ruardean Hill in the distance. The lower part of this bowl was filled with water from the melting ice, which flowed out through Soudley and down to Blakeney. See the bowl: www.geograph.org.uk/photo/854797

Here is another view that conveys a sense of the bowl from the bottom: www.geograph.org.uk/photo/759954

These scenes are of the secondary slope in Cinderford, sloping down from the main slope, created by the impact crater, to the slope created by the flow of meltwater out through Soudley:

www.geograph.org.uk/photo/728705

www.geograph.org.uk/photo/728712

www.geograph.org.uk/photo/132478

www.geograph.org.uk/photo/728719

In this photo, at the centre of Cinderford, you can see the secondary slope angling downward off the main slope: www.geograph.org.uk/photo/132426

This is a photo taken closer to Soudley, where the water that went past Cinderford flowed out on it's way to the Severn Vale: www.geograph.org.uk/photo/1605897

This flow ended up at Blakeney, closer to the Severn River. Here is a view of the valley there: www.geograph.org.uk/photo/533100

The main flat slope of Cinderford, shaped by the impact crater can be seen in the fifth and sixth photos from the top on my photo blog, http://www.markmeekphotos.blogspot.com/ Cinderford is the town in the distance in these views taken from Drybrook. If you look closely, you can even see the gap in the distant hills over to the right where the water ultimately flowed out at Soudley.

U-SHAPE

I would just like to show a couple of more scenes of that U-shape that moving glaciers tend to leave on the ground. This U-shape to the ground is to be seen all over the Forest of Dean, looking northwest from Yat Rock, looking northwest from Drybrook and at the bottom of Lydbrook. Here are more such scenes which I noticed:

www.geograph.org.uk/photo/1815171

www.geograph.org.uk/photo/683497

The Slopes Of Tonawanda And Buffalo

On my Niagara natural history blog, http://www.markmeekniagara.blogspot.com/ there is a posting "Tonawanda And The Niagara River". That posting is mainly about the City of Tonawanda north of the Interstate 290 highway. This posting focuses on the Town of Tonawanda south of that highway. The two postings are not connected and readers can read one without the other.

Every area has something about the way things are done there that is confusing to outsiders. The world would not be as interesting if that were not the case. In the Niagara area on the U.S. side, it is this "town" system. A "town" is not only a mid-sized settlement, larger than a village but smaller than a city, it also refers to a newer urban area just outside of the original older city or village.

That is why there may be both a city and a town, or a village and a town, with the same name. In this case, it is Tonawanda.

Come to think of it, my native Britain plays games with towns too. In Gloucestershire, it may be confusing as to why Gloucester is a city while nearby Cheltenham, which is about the same size, is only a town. There, the definition involves cathedrals. Gloucester has a cathedral while Cheltenham doesn't.

Anyway, Tonawanda, NY is generally considered as a northern outer suburb of Buffalo. But it is large enough so that if Buffalo were not nearby, it would be a significant city in it's own right.

The landscape of the Town of Tonawanda is mainly flat. But a closer look reveals several very significant glacial features that were formed at the end of the last ice age about 12,000 years ago.

Here is a map link if you would like http://www.maps.google.com/ or http://www.multimap.com/

These glacial features are the result of two different slopes in Tonawanda. There is an overall southward slope to the underlying rock strata here. But there is also a somewhat more limited westward slope to the strata, that has produced results of it's own.

SOUTHWARD SLOPE

Let's first look at the major southward slope. At the intersection of Military Road and Sheridan Drive, is is easy to see this slope if we look southward, in the direction of Buffalo. On Kenmore Avenue, looking along the side streets in either direction, this gradual southward slope is also apparent. Notice how Delaware Avenue rises going northward from Kenmore Avenue.

Niagara Falls Boulevard also gradually gets lower in elevation as we proceed southward. This can be seen from the intersection of Sheridan Drive and the Boulevard and also further north at the intersection of Robinson Road and Niagara Falls Boulevard.

This southward slope can be observed all over the area. Even near Tonawanda Creek, if we look south from East Niagara Street along Carney and Douglas Streets. This can also be seen if we look southward along East Longs and Fillmore Avenue. Looking across Tonawanda Creek to the North Tonawanda side, it is clear that there also, the streets slope southward toward the creek.

At the intersection of Colvin Boulevard and Brighton Road in Tonawanda, we can see that we are in a broad and shallow bowl if we look in any direction. Now notice on a map that this intersection is directly south of the southernmost extents of both Tonawanda and Ellicott Creeks.

This is due to a glacial thrust southward along the underlying rock strata at the end of the last ice age. The thrust plowed up the ground, making an interruption in the general southward slope and the creek naturally used that as it's bank. The same thrust continued and produced the broad shallow valley in the ground.

Just west of Niagara Falls Boulevard on Brighton Road, notice that the road is actually atop a broad, low ridge that extends for some distance in either direction if we look to the north and south along the side streets. Now, if we look at the so-called Green Acres North area east of Niagara Falls Boulevard and north of the Interstate 290, we see that the area actually occupies a broad valley.

A glacial thrust that was parallel to the one at Colvin and Brighton pushed up the dirt to form the valley at Green Acres North and deposited it to form the ridge that can be seen along Brighton.

Notice that Niagara Falls Boulevard is actually in a shallow valley around the intersection with Brighton Road. This was formed by another glacial thrust, a massive berg of ice which broke free from the main glacial sheet as the last ice age ended and slid along the slope of the underlying rock strata.

This vast iceberg continued southward, plowing up the ground in front of it as it went along. It finally came to a halt around where the intersection of Niagara Falls Boulevard and Kenmore Avenue is now located. The halt to it's slide was most likely the result of both the melting of the ice berg and the growing pile of soil and debris which it plowed up in front of it.

At the intersection of Niagara Falls Boulevard and Kenmore Avenue, we are at the deepest point of what was once a fairly deep lake for it's size. The eastern side of the former lake is much steeper than it's gradual western side. Tops parking lot occupies part of the former lake bed. To the west, we can see that the former lake began at Fairfield Avenue.

The University of Buffalo, just to the south on Main Street, is built atop the vast amount of debris which the iceberg plowed up in front of it as it slid southward. The reason that there is a terrace between the former lake and this pile of glacial debris must be because there is a glacial impact crater involved.

After the melting berg had come to a halt. It fractured laterally in the manner of the other glacial impact craters I have described in my Niagara blog and pushed the debris pile backward to the south. This is where the university is now located and Main Street is built upon the resulting terrace between the two.

If we go north along Capen Boulevard from Kenmore Avenue, we can see a cross section of this former lake. The lake gets more shallow as we proceed north. It appears probable that the former shore of this lake, let's call it Lake Kenmore since there already is a former Lake Tonawanda, is where Sheridan Drive is now located.

Lake Kenmore is the prominent feature in the Tonawanda-Kenmore area produced by icebergs at the end of the last ice age sliding across the slope in the underlying rock strata. But the southward slope continues as we go southward into Buffalo.

On Main Street in downtown Buffalo, it can be readily seen that the elevation of the land to the west of Main Street is considerably higher than the land to the east of Main Street. The East Side of Buffalo was once a wide raceway of glacial fragments sliding southward at the end of the last ice age. This difference in land elevation is because these ice bergs plowed away the ground as they went.

One result of this raceway and the plowing up of the ground is the ridge along High Street in downtown Buffalo. It is the ridge atop which Buffalo General Hospital is built. Ridges like this result when the sliding icebergs melt so much and have plowed up so much ground in front of them that they cannot move any further. The ground in front of them remains where it is.

The High Street Ridge only extends eastward for a certain way. Further east, the sliding icebergs pushed much further south. In fact, all the way to what is now Ridge Road in Lackawanna, to the south of Buffalo. This road is built atop a ridge that was formed in the same way as the High Street Ridge.

The ridge extends eastward toward South Park Avenue. We can see on a map that there must have been some westward momentum to the glacial fragments that produced the ridge upon which Ridge Road is built.

(Note- While you are in Lackawanna, you can have a look in Father Baker's Basilica at the intersection of Ridge Road and South Park Avenue. It is really awesome).

WESTWARD SLOPE

The westward slope to the land, in Tonawanda and elsewhere, is not quite as prominent as the southward slope. But it has produced some signifigant landscape features nevertheless.

I pointed out how the ridge upon which Ridge Road in Lackawanna is built is seen to have a westward as well as a southward momentum in the glacier that produced it. We can see this reflected in Main Street in downtown Buffalo. Main Street here is built roughly along the edge of where the East Side Raceway operated.

Notice that Main Street does not run exactly north-south, but is tilted slightly southwest to northeast. This makes it virtually perpendicular to Ridge Road, which shows that Ridge Road was produced by ice sliding southward through this raceway.

We can see the western slope to the underlying rock strata in a number of places, just as we could the southward slope. In the far northern extent of Tonawanda, Creekside Drive can be seen to get progressively lower in elevation as we go westward from Niagara Falls Boulevard. Looking east along the side streets from Parker Boulevard, we can also see how the ground gets higher going east.

Brighton Road gets lower in elevation west of Eggert Road. Sheridan Drive has a long and gradual drop in elevation going west from Delaware Road, which continues west of Military Road. The same westward slope can be seen on Ensminger Road, parallel to the north of Sheridan Drive.

There is a peak in the land elevation at the intersection of Sheridan Drive and Delaware Road. This was created in the same way as was Lake Kenmore, described above. A massive berg of ice slid westward along this slope in the underlying rock strata, plowing up the ground as it went, until it could not go any further.

This peak in the elevation of the land is actually part of a ridge. North of Sheridan Drive, we can see that there is a ridge which runs northwest to southeast and crosses both Delaware Road and Delaware Avenue.

South of Sheridan Drive, we can see that there is a drop in elevation to both the east and west of Delaware Road, but the drop is less to the west than to the east. This is because the road occupies a ridge that was formed by a massive iceberg sliding from the east along the westward slope of the ground.

There is another glacial ridge nearby. On Ensminger Road, just west of Military Road, we go over a ridge. On Military Road, we can see that there is a wide, shallow dip in the level of the road from the Interstate 290 highway to Oakridge Avenue.

This is the result of another iceberg plowing westward and creating a glacial ridge.

Now, let's proceed further west along Sheridan Drive. If we look south along Riverview Boulevard, we again see the drop in land elevation going southward.

But if we proceed down this street, it becomes apparent that this was once a lake. Looking further west along Riverview and we see that the elevation increases. The bottom of the lake was clearly at what is now the intersection of Riverview Boulevard and Woodward Avenue.

Notice that the deepest point of this former lake was toward it's southwest. This is because the lake, like Lake Kenmore, was formed by a massive iceberg sliding across the ground with both southward and westward slopes until it came to a halt.

We can also see that the same combination of the westward and the southward slopes led the sliding icebergs to form the Delaware Ridge, because it is aligned from northwest to southeast.

I find it interesting that if we draw a line approximately bisecting this former lake, let's call it Lake Sheridan, and passing through it's deepest point.

The line turns out to be perpendicular to the Delaware Ridge. This means that there could be a connection between the two, aside from the fact that they were both formed by the same south and west slopes to the ground.

This seems to indicate that another glacial impact crater could have occurred. When the massive berg of ice that formed the Delaware Ridge came to a halt, it could have fractured laterally like so many bergs that formed other glacial impact craters. But the underlying rock strata was sloped enough that instead of forming a glacial impact crater, the berg of ice slid along the slope until it came to a halt itself. Then it melted and the result was this lake.

The lake, Lake Sheridan, would have continued as a lake for quite some time, as would Lake Kenmore, because the slope of the land would have channelled water to it.

The reason that I even noticed this former Lake Sheridan is that I could see the present Two Mile Creek that crosses Sheridan Park, parallel to East Park Drive, once must have been much larger than it is today. The valley around the creek obviously was not carved by the little bit of water that flows through it at present. I looked southward along Riverview Boulevard to see if I could find out where all of this water once came from and, I noticed the former lake.

This can be easily seen in the satellite imagery.

Furthermore, I notice that the considerable valley around Two Mile Creek is itself parallel to the ridge that cross Ensminger Road just west of Military Road, let's call it the Ensminger Ridge. Could the same thing have happened here, the glacier that formed the ridge fracturing laterally and sliding? I consider it a good possibility. Then, the lake drained northward through the valley that was produced.

There is another former drainage channel that crosses Sheridan Park, it is west of Two Mile Creek and eventually merges with it. There is also a large former drainage channel which crosses the main roads just to the south and parallel to the 290 Interstate highway and this appears to have joined two mile creek also.

Of course if we go further into Tonawanda, north of the Interstate 290, the ground elevation begins to get lower going north. But this is the former shore of the vast Lake Tonawanda, which I described in the posting "Tonawanda And The Niagara River" and even this was the result of the glacial slide southward plowing the ground along in front of it.