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NEW YORK STATE MUSEUM 



When the waters north of the escarpment had subsided to the 

 level of the outlet at Rome, a long period of stability ensued, during 

 which extensive and well marked beaches were formed by the waves. 

 This comparatively long-lived body of water has been named Lake 

 Iroquois, and its outline is shown in the accompanying map (fig. 

 lo) reproduced from Gilbert's History of the Niagara river. The 

 Iroquois shore lines in this region may be seen in the ridge road 

 which extends eastward from Lewiston, and westward from 

 Queenston, closely skirting the foot of the escarpment. 



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Fig. 10 Map of Lake Iroquois ; the modern hydrography shown in dotted lines. (After Gilbei't) 



A fine section of this old beach is seen just behind the railroad 

 station at Lewiston. Here the layers of sand and gravel slope 

 steeply ioward the southeast, and many of them are irregular and 

 wedge-shaped. Some of the beds, a foot or more in thickness, con- 

 sist entirely of rounded pebbles, with little or no sand between, form- 

 ing a porous mass of '' loose gravel ". The prevailing rock of the 

 pebbles is the Medina sandstone, derived from the neighborhood,, 

 and the pebbles are always well waterworn, and commonly of the 

 flattened type characteristic of thin bedded rocks. Mingled with 

 the beds of coarse material are layers of fine sand, the structure of 

 which is well brought out by exposure to wind and weather. Not 



