6. JACKSON TOWNSHIP. F\ 233 



The Onondaga shale in Jackson township has yielded 

 many of the interesting fossils, to be described in Vol. 2. 

 (See Silurian fossil list.) 



Section of Onondaga variegated shale from the 19th mile 

 post on the valley road from Bloomfield to LJnslow's mill. 

 See Page Plate' XXL 



Gray calcareous shale with wrinkled or cracked surface. 

 2' Green shale. 

 4' Red shale. 



1' Brown sandstone and shale. 

 120' Ground imperfectly exposed. In this space is the Bloornneld sand- 

 stone. 

 116' Limestone and lime shale, (in soil.) 



Red shale, thin. 

 40' Gray shale and limestone. 



4' Red shale. 

 144' Gray shale. 



Thin limestone. 

 32' Gray shale. 



Red shale, thin. 

 48' Gray shale. 



Red shale, thin. 



30' Gray shales with bands of limestone, (spring.) 



4' Red shale. 



2' Gray shale. 



6' Red shale. 



72 Gray shale. 



48' Gray and red shale, mostly. 

 3' Yellow shale. 

 125' Yellow and gray shale. 



801' 



The Lower Helderberg (Lewistown) limestone, No. VL. 



A broad belt of this limestone enters Jackson township 

 from the northeast, consisting of two synclinal troughs, be- 

 tween which runs an anticlinal axis, (perhaps the fifth of 

 Rogers' enumeration.; The belt of limestone gradually 

 narrows by (he disappearance of the southern part, but the 

 northern synclinal continues onward toward New German- 

 town, narrowing as it passes westward. The synclinal fold 

 is well seen at Mr. Hall's quarries, north of Blain, where 

 about 50 feet of the limestone are exposed. From these 



