137 Devonian of Southern Indiana 



tucky has been generally explained as due to thinning out*. 

 Prof. N. S. Shaler did not recognize any stratigraphic break at 

 the base of the New Albany shalef and regarded it as the equiv- 

 alent of the New York Devonian formations down to the Oris- 

 knay|, where the Cornifernus was wanting in the Kentucky sec- 

 tion. The writer has found sedlions which .show unconformity 

 between the New Albany shale and the beds below in Kentucky. 

 This interval of erosion which has been detecfted at the base of 

 the Black shale explains the entire absence of the Devonian lime- 

 stone at many localities and its extreme thinness where present. 



*Pal. N. Y., vol. 5, pt. 2, p. 140. 



tGeol. Surv. of Ky., n. ser., vol. 3, p. 174. 



t " " " " " " " " " 173- 



