io6 



THE HABITAT OF THE EURYPTERIDA 



more especially due to difference in origin. The sediment of the Bertie 

 and its fossils came from the continent of Atlantica, and those of the 

 Pittsford from Appalachia. This is more fully discussed in a subse- 

 quent chapter (see p. 229). 



5. THE BERTIE WATERLIME 



The Bertie waterlime of Upper Siluric or Monroan age is con- 

 fined to central and western New York, and the adjacent portion of 

 Ontario, Canada. It is a gray, fine-grained, argillaceous calcilutyte 

 of a remarkably uniform character, showing practically no variation 

 in texture from place to place. Chemical analysis has shown it to 

 be an impure limestone, high in magnesia, silica and alumina. The 

 following analysis is that of an average specimen (39, 101). 



Si O2 11 .48 



AI2O3 i7-S° 



Iron 0.90 



CaC0 3 42 • 75 



MgC0 3 20.35 



K 2 1 . 00 



Na CI o . 80 



Combined water and loss 5.22 



A typical section of the Bertie is exposed at Buffalo where Pohl- 

 man has recorded the following succession the lower part being ob- 

 tained from borings. (See also Grabau, 82, 115). 



Akron dolomite 



Feet 



Bertie 



Waterlime, about 7 



Shale and cement rock in thin streaks 25 



Tolerably pure cement rock 5 



Shale and cement rock in thin streaks 13 



Pure white gypsum 4 



Shale 2 



White gypsum 12 



Shale 1 



White gypsum 4 



Shale and gypsum, mottled 7 



Camillus \ Drab colored shale with several thin layers of white 



gypsum 58 



Dark colored limestone 2 



Shale and limestone 4 



Compact shale 3 



Gypsum and shale, mottled and in streaks, approxi- 

 mately 290 plus 



