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.