Devonian Shales of Ohio and Pennsylvania. 



45 



In summing up the evidence on this question then we must 

 admit that there is at present no great uniformity of opinion. 

 The most competent autliorities are divided. The writer is 

 disposed to beHeve that the evidence rather favors the Devo- 

 nian age of these rocks and they are therefore so represented 

 on the table of correlations. 



Fig. 2. 









^,^. 



H? 



H 





1 



1 



\ 



LEQE ND 



ill 



1^^^ 



^tm 



Wl 



BloLck SKole. 

 Red SKo-le. 



Sarvcist orvc 

 Ltrncst OTwc 



r-Tao 



TOP 





LI M E - 





,ST N g .S 



Fig. 2. Well records showing the thickness and character of the Devo- 

 nian shales from central Ohio into western Pennsylvania. 



Explanation of Figure 2. 



In figure 2 are represented six carefully selected well records. 

 It is not an easy matter to secure well records which penetrate 

 the entire thickness of the shales and also give their character 

 in detail ; and those chosen are not as complete as desired. 

 Still they will indicate in a general way the nature and thick- 

 ness of the Devonian shales from the longitude of Sandnsky, 

 Ohio east to that of Erie, Pennsylvania. Section A is from 

 Norwalk, Ohio and thus near the western outcrop of the shales 



