HELDERBERG DIVISION. 
341 
This rock is an argillo-calcareous grit, of a fine grain, almost slate, and is often crumbling 
into small fragments when exposed to the weather. In some places it is almost black, more 
frequently grey or buff-colored ; and when weathered, grey and light buff. It has a thickness 
of fifty or sixty feet in many places in the First district, being a much thicker rock than the 
overlying members of the Helderberg division. It extends from the west line of Schohaiie 
4. Cauda-galli Grit. 
Fi?. 18. 
