to the Ohio Shale Problem. 181 



quent in age to the Chagrin, I welcome every bit of evidence 

 that lie may bring toward proving their fannal unity. In fact, 

 I regard this strong faunal agreement as the most important 

 feature of the deductive part of the evidence on which the 

 views herein advocated are based. 



Summary of conclusions. 



(1) I contend that the fishes and other fossils commonly 

 credited to the Huron shale of Ohio have never been and, as 

 I believe, can never be shown to be really of the age of the 

 upper Devonian of New York. Their common acceptance as 

 bona Jide Devonian fossils rests solely on the unproven and 

 probably mistaken belief that the beds in which they are found 

 are older than the Chagrin, which is unquestionably upper 

 Devonian. If the Huron is as I claim younger, then its fossils 

 can not be really Devonian species unless the boundaries of 

 this system are expanded upward beyond the limits of the New 

 York standard. 



(2) Regarding the Chagrin 1 claim that this formation has 

 been unquestionably recognized in northern Ohio only to the 

 east of Lorain County. In this stretch there is no difficulty 

 whatever in drawing the boundary between the Chagrin on 

 the one side and the Olmsted and Cleveland on the other, so 

 long as the latter two continue to be represented in the section. 

 The contact between the Chagrin and the other two in this 

 stretch seems, moreover, to be unconformable by overlap and 

 to mark a stratigraphic hiatus of considerable importance. 



Regarding the beds to the west of Avon, or of some other 

 point in Lorain County, that have been referred to the horizon 

 of the " Erie" or Chagrin, I contend that the evidence for such 

 reference is in every case undecisive ; in most it is clearly open to 

 question, and in others already disproved. (Yide Newberry, 

 U. S. Geol. Survey Monog. xvi, 1889, p. 127, where he corrects 

 an error and states that " none of the fossil fishes described 

 from northern Ohio should be credited to the Huron," and 

 " that all the outcrops of black shale (along the lake shore) in 

 Cuyahoga and Lorain counties belong to the Cleveland (more 

 likely Olmsted) shale.") So far as I can see, there is no break in 

 the Huron-Cleveland section in Huron County and certainly 

 none between that small middle part of the section which is 

 referred to as "Erie" by Read and others, and that upper por- 

 tion which they doubtless correctly recognize as Cleveland. 

 If these correlations by Newberry and Read were correct, the 

 absence of a break at the latter horizon would be most extra- 

 ordinary in view of the fact that a break is clearly indicated to 

 the east of Lorain Countj T between the true Chagrin (" Erie ") 



Am. Jour. Sci.— Fourth Series, Vol. XXXIV, No. 200.— August, 1912. 

 13 



