36 NEW YORK STATE :\IUSEUM 



Camillus shale 



This term has been appHed to the gypseous shales lying above the 



horizon of the salt and forming one of the stratigraphic integers of 



the Salina group. It is the lowest formation represented on the map 



and only the upper portion of the shales to a thickness of about 40 



feet is here exposed. The rock is a soft, dark gray shale containing a 



varying proportion of gypsum, usually in thin uneven seams or 



lenses. It is abundantly exposed and has been extensively quarried 



in the towns of Camillus, Elbridge and DeWitt in Onondaga county, 



Springport in Cayuga county and Phelps in Ontario county and is 



commonly known as " plaster rock." Though it is present in this 



area it has been excavated by erosion and then covered so deeply by 



alluvial accumulations through the Onondaga valley that at no place 



are the shales well displayed, and the estimate of its thickness as 



given is based on data derived from adjoining regions. Farther 



north in the town of DeWitt outside the boundar}^ of this map, this 



rock is much thicker and at about 100 feet below the top of these 



shales, near the Heard quarries, there are some layers of limestone 



which contain in considerable abundance the species Leper ditia 



s c a 1 a r i s Jones. 



Bertie dolomite 



. . . • 



This division of the Salina group, taking its name from its ex- 

 posures in the township of Bertie, Ontario, is here composed of fine 

 dark gray waterlime weathering to light drab, with a brownish or 

 yellowish shade. At the base of the entire exposure which so far 

 as exposed and calculated, is about 15 feet thick, 11 feet are thinly 

 laminated. The upper stratum, 4 feet thick, is harder and but 

 slightly schistose. In the western part of the State the rock becomes 

 more compact and from it is quarried the very large amount of 

 waterlime cement manufactin-ed at Akron and Buffalo. It is not 

 however used for that purpose in this vicinity, the heavier layers of 

 cement rock higher in the section being preferred. Exposures of 

 this formation are to be found along Butternut creek below James- 

 ville and this is the only place where the rock appears to advantage 



