^0 Cincinnati Society of Natiiral Histojy. 



THE GEOLOGY OF CINCINNATI 



By Prof. Joskph F. James, 



Custodian of Cincinnati Society Natural History. 



(Read May 4, 1886.) 



The City of Cincinnati occui)ies one of the most interesting 

 geological positions on the North American Continent. y\s has 

 been truly expressed, the hills of Cincinnati are counted as classi- 

 cal ground by geologists of all lands, and "Sir Chas. Lyell said, 

 after visiting the hills and looking over the collections that had 

 been made of their treasures, that there was no other locality 

 known in the world where so large a number and so large a va- 

 riety of well preserved Lower Silurian forms could be so easily 

 procured."* 



But beside the fossil treasures which exert so potent an influ- 

 ence over the minds of collectors, there are other matters of great 

 interest connected with the ground upon which the city stands, 

 and by which it is surrounded. Few attempts have been made to 

 study the surface geology of the vicinity. The chapters in the 

 Ohio Geological Surveyf contain about all that has been written 

 on the subject, so that it is by no means exhausted. To elucidate 

 some of the problems relating to the geology and topography of 

 Cincinnati and its vicinity is the object of the jn-esent paper. 



That subject of much controversy among geologists, viz : 

 whether the rocks as exposed in our neighborhood should be 

 known as the Hudson River and Utica slate, or as the Cincinnati 

 Group, will detain us but a short time. Prof. James Hall, as the 

 leader among Eastern geologists, insists that the rocks are of the 

 same age as the Hudson River Group, and should be so called. 

 Dana follows him, as, in fact, do most of the Eastern geologists. 

 But Newberry, Orton, Meek and Worthen, four geologists who 

 have given much attention to the exposure in Southwestern Ohio, 

 insist that the rocks are not equivalent to either the Hudson River 

 or the Utica slate ; but that there is a commingling of Trenton, 

 Hudson River, Utica Slate, and some peculiar fossils found in 

 none of these which entitle the exposure to a distinct name, and 

 so they call it the Cincinnati Group. It seems well chosen and 



*C)hio Geol., I., p. 3S5. 



fVoI. I., chaps. 4, 13, 14 niid vol. 11., parts of chap. 70. 



