780 NEW YORK STATE MUSEUM 



city line. The Onondaga limestone in Erie county forms a tliin 

 band between tlie hydraulic limestone and the overlying Cornif- 

 eroiis limestone. It varies in color from blue gray to a light 

 gray, and also varies in thickness^, reaching its maximum of 35 

 feet in Fogelsonger's quarry at WilliamsAdlle. It is the same 

 thickness 2 miles farther on but then begins to thin out rapidly. 

 The formation in Erie county, instead of being of one continuous 

 bed, is really a series of lenticular masses occurring at the same 

 horizon. The C'orniferous limestone in Erie countv forms some- 

 what of an escarpment, as already mentioned. The rock outcrops 

 are not as a rule very extensive, but good ones occur a few miles 

 below Millgrove near a dam across Endicott creek, and again in 

 the bed of the same stream for 3 miles below Wilhelm, and also 

 near the same place. Again this limestone is found in Gage 

 creek at Kieffer's quarry near the transit road about a mile west 

 of Lancaster. 



Hydraulic limestone. This extends through Williamsville, 

 Clarence and Akron. Along the whole line of its outcrop it has 

 been quarried at numerous places but generally only for building 

 purposes. The section at the works of the Buffalo cement co. 

 gives the following relations of the three limestones: flint and 

 limestone, Corniferous, 3 to 9 feet; Onondaga lime, 5 feet 8 

 inches; loose friable limestone, 6 inches; gypsum crystal, 6 inches; 

 hydraulic limestone, porous, known as bullhead, Y feet; cement 

 rock used for burning, 3 feet 8 inches; impure hydraulic lime at 

 bottom (pL 36). 



The bullhead stratum furnishes the greater part of the water- 

 lime used for building purposes. 



Onondaga limestone. One or two of the lenticular masses al- 

 ready mentioned occur near Williamsville in the quarry of Eo- 

 gelsonger & Young. It is highly fossiliferous and quite pure, 

 as shown by the following analysis made by H. Carlson and quoted 

 by Bishop.^ 



1 Geology of Erie county, {see ISth an. rep't N. Y. state geol. p. 331) 



