274 OBSERVATIONS ON THE GEOLOGY OF THE WESTERN PENINSULA. 



To compare directly the formations as they appear in the Appalachian 

 chain with their western and northern outcrop in Ohio and New York, would 

 not, we believe, furnish satisfactory identifications; for we already know the 

 great alterations in type which most of them undergo in passing northward 

 and westward under the broad bituminous coal field of Pennsylvania and Ohio. 

 To trace them continuously by their lithological and fossil characters, north- 

 eastward to the Mohawk, and thence westward through New York, seemed to 

 us to be rendered necessary by the thinning out of some formations, the coming 

 in of others, and the suspected partial changes in the organic remains of all; and 

 to be, in fact, the only method compatible with the caution essential in such re- 

 searches. 



After devoting considerable pains to a preliminary study of the formations 

 of western New York, we resolved, if possible, to keep in view some easily re- 

 cognised horizon among the strata, and by working round Lake Erie through 

 Upper Canada and Michigan, form a junction with the rocks of Ohio. 



Believing that by this procedure we have ascertained the place, approxi- 

 mately at least, of the rocks of parts of Upper Canada, Michigan and Ohio, we 

 propose in the present paper to give a concise account, first, of their range 

 from the Niagara river to Lake Huron, and, secondly, of the course of some of 

 them from Lake Huron into Ohio. 



PART L 



Of THE Range of the Niagara River Rocks through Upper Canada. 



Range of the Niagara Limestones. — This group of rocks, in its extension 

 across Upper Canada, continues, as in New York, to form a great part of the 

 escarpment of the Mountain Ridge. Its line of outcrop, thus marked, follows 

 a nearly west course from Queenstown and the Niagara river, to the head of 

 Lake Ontario; then bending in a rapid curve around the head of the Lake to 

 near the foot of BurUngton Bay, it strikes off in a N. N. W. direction towards 

 Lake Iroquois, or the Georgian Bay of Lake Huron, the southern shore of 

 which it reaches in the neighbourhood of Penetangasheen. From the Niagara 

 river to the head of Lake Ontario, the arenaceous rocks composing the Grey- 

 band and the other strata immediately beneath the Niagara limestone group, 

 form, as in the neighbouring parts of New York, alow bench adjoininor the base 



