284 OBSERVATIONS ON THE GEOLOGY OF THE WESTERN PENINSULA, &C. 



before reaching the axis in Ohio, we are disposed to regard it and the Cincin- 

 nati limestone, which both occupy the same position under the shales beneath 

 the pitted rock, as approximately contemporaneous. In thus viewing the lime- 

 stone of Cincinnati, we regret to find our conclusions apparently at variance with 

 those of Mr. Conrad, now decidedly the first authority in our country, in ques- 

 tions of Palaeontology. He expresses the opinion in his last annual report, that 

 the limestone of Cincinnati is "the equivalent or continuation of the black lime- 

 stone of Trenton Falls," in New York. But to bring up a formation so low 

 in the Appalachian series, the anticlinal axis must previously elevate not only 

 the gypseous and Niagara strata, but the prodigiously thick groups of shales, 

 limestones, slates and sandstones, which rest above the Trenton limestone, and 

 which, if thus elevated, would have conferred upon Ohio, Indiana, and Ken- 

 tucky a wholly different geology, mineral wealth, and physical geography 

 from that which we now behold. 



To present, in conclusion, a simple generalization of the results aimed at, 

 respecting the range and distribution of the rocks which cross the Niagara 

 river, let us conceive the strata forming the expanded plain bounded by the 

 Mountain terrace, gently to decline to the S. W., in upper Canada and Ohio, 

 while the flat but extensive anticlinal axis traverses the slope from Kentucky 

 to the western side of Upper Canada. In these two conditions we discern the 

 cause first of the general north-western strike of the pitted limestone, which 

 carries it in the direction of Cabot's Head, and the Manitoulin Islands, and 

 secondly of that long south-western strike which affects the same stratum in 

 another outcrop, as far south as the Maumee, and expands the overlying and 

 next subjacent rocks, in a broad zone across the Ohio river into Kentucky and 

 Tennessee. 



