124 



The extensive anticlinal line, traced from the western side of Ca- 

 nada to the Maumee, crosses the Ohio river somewhere in the vicinity 

 of Louisville, and terminates probably in Kentucky, imparting a gene- 

 ral south-south-west strike to all the strata of western Canada, east- 

 ern Michigan, Ohio and Indiana. The lowest formation near Lake 

 Erie which the axis elevates to the surface, is the pitted limestone. 

 But further to the south-south-west, still lower formations appear; the 

 cliff limestone, at the base of which we place the pitted rock, being 

 underlaid, according to Dr. Locke, by marly shales, that rest upon 

 an extensive formation of blue limestone, well exposed around Cin- 

 cinnati. These shales are regarded by the authors of the paper as 

 representing the gypsum shales of New York. Influenced by a cer- 

 tain degree of correspondence in the fossils of the Cincinnati lime- 

 stone, and by other considerations, they view this latter formation to 

 be approximately contemporaneous with the Niagara or Lockport 

 limestone, but to include beds nowhere met with in New York. 

 Apart from the indications afforded by the fossils, a reasonable in- 

 ference is drawn from its progressive thickening westward, that it 

 ranges at least as far as the axis on the Ohio. The Cincinnati lime- 

 stone, occupying the same position below the shales under the pitted 

 limestone, as the Niagara formation, may, if we use the term with 

 proper restrictions, be regarded as its equivalent. In thus viewing 

 the limestone of Cincinnati, the authors find their conclusions at va- 

 riance with those of Mr. Conrad, for whose researches in Palsentology 

 they avow the highest respect. In his last annual report, that geolo- 

 gist regards the limestone of Cincinnati as the equivalent or continua- 

 tion of the black limestone 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, with a mineralogical character and 

 physical geography unlike those which now belong to them. 



In conclusion, a simple generalization is presented of the results 

 arrived at respecting the range and distribution of the Niagara river 

 rocks. The strata overspreading the plain, bounded by the mountain 

 terrace, are conceived to decline gently to the south-west 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 the authors find a reason, first, for the general 



