82 GEOLOGY OF ERIE COUNTY 



of western New York has lifted upward to the north 122 feet 

 from the Pennsylvania state line to Marilla, or measured in Erie 

 county the uplift has been 55 feet between North Collins and 

 Marilla, so that Marilla which was originally at the same level as 

 North Collins has been elevated 55 feet above it- The rate of 

 uplift is not the same everywhere but it increases toward the 

 north. From the state line to North Collins it rises 67 feet in 

 48 miles or at the rate of 1.4 feet per mile. But from North 

 Collins to Marilla it rises 55 feet in 26 miles or at the rate of 2.1 

 feet per mile. Outside our county this increase continues until 

 at the east end of Lake Ontario it rises at the rate of 6 feet per 

 mile. Southward and westward the tilting decreases until there 

 is little or no deformation to be detected in northern Ohio on the 

 Whittlesey beach. (Leverett, 755.) 



There can be little doubt that this tilting of the land to the 

 north and the masking of old drainage channels by glacial debris 

 have contributed materially to the change of direction of flow of 

 our streams. Before the glacial period the upper tributaries of 

 the Allegheny seem to have flowed northward joining finally the 

 waters of Cattaraugus creek and continuing westward into the 

 depression now occupied by Lake Erie. The tributaries of the 

 middle Allegheny also seem to have flowed north into the same 

 depression. The glacier dammed these drainage channels and 

 caused the Allegheny waters to seek a pathway southward. 

 Aided by the enormous amount of glacial water derived from the 

 melting of the ice, they found a course by reversing the flow in 

 the upper Allegheny. This led them to the lower Allegheny and 

 to the Mississippi. 



Cattaraugus creek, deprived of its main southern tributaries 

 by the reversal of the drainage south of the glacier, abandoned 

 that portion of its valley lying between Zoar and Gowanda and 

 since the glacial time has cut a new channel. From Gowanda 

 to the lake it occupies its ancient channel but it has swung 

 sufficiently in it to make rock walls at several points. 



Eighteen Mile creek, which, before the glacier, had drained 

 westward separately through the channels of its two present 

 branches into the Lake Erie depression has been forced to cut a 

 new channel, instead of excavating the drift-filled channels of 

 its lower valley. The new channel of the west branch, little 

 wider as yet than the stream bed, begins below Clarksburg 



