BUFFALO SOCIETY OF NATURAL SCIENCES 81 



In Erie county Lake Dana is marked by rather faint gravel 

 and sand beaches following the 620 foot contour. The strongest 

 encircles the ridge of till which bears the Ridge Road in Lacka- 

 wanna. This ridge would have appeared as an island in the 

 lake. Gravel pits have been opened along this ridge to the depth 

 of fifteen feet. North of the ridge are two small till ridges which 

 show wave cut terraces. The till ridge north of Ebenezer bears 

 a gravel pit on its north side which is on this contour and, at the 

 same level, sand beaches are to be seen on Utica street, Buffalo, 

 and neighboring streets, and at Pine Hill just east of Buffalo. 



Lake Dana was drained eastward through the Mohawk 

 valley. It was lowered by successive stages when lower and 

 lower channels were uncovered over the Mohawk divide. 



The country now included in the northwest corner of Erie 

 county remained under the water of Lake Dana until the level of 

 its outlet fell below the level of the top of the Niagara escarpment, 

 the Mountain ridge. Its successor below the Mountain ridge 

 was Lake Iroquois which formed the beach that is now the 

 Ridge Road running from Lewiston eastward across Niagara 

 count}-. 



With the gradual passing away of the great glacier from Erie 

 county its present topography began to appear. Some of its 

 ancient stream valleys had been filled and obliterated by deposits 

 of drift. Some had been transformed into long, narrow lakes. 

 The wide, sloping hills, the result of ages of erosion, had been 

 covered deeply with glacial debris. Great lakes and glacial 

 streams had left their beaches and bars high up in the hills. 

 Glacial streams had eroded valleys and had built the debris into 

 deltas in the lakes, and these were left after the recession of the 

 waters as long, sandy, flat-topped plains. Stretching across the 

 county were the great moraines left at the ice front and over all 

 was a sheet of glacial till. 



Since the recession of the ice sheet the agencies of sub-aerial 

 erosion have been at work shaping the topography of the 

 county. The melting away of the ice was followed by a gradual 

 uplift of the land surface at the north and this uplift is still going 

 on. The elevation of the land since glacial times can be easily 

 measured by the differences of level in the beaches of the glacial 

 lakes. These beaches, naturally, were laid down originally at 

 the water level of these lakes. Measured by this level, the land 



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