120 



to the Sandwich Islands and Upper California, by Thomas 

 Nuttall;" which was read and referred to a committee. 



Professor Henry D. Rogers read a communication by his 

 brother, Professor William B. Rogers, and himself, entitled, 

 "Observations on the Geology of the Western Peninsula of 

 Upper Canada, and the Western part of Ohio;" which was re- 

 ferred to a committee. 



The authors commence by expressing their views of the importance 

 of determining the relations of the rocks of the western states to the 

 formations of the Appalachian system, as they are developed in New 

 York, Pennsylvania and Virginia. They deem this comparison es- 

 sential to the full understanding of those gradations in type which 

 elucidate the physical changes that accompanied the production of the 

 strata. The difficulties of the investigation are then alluded to, con- 

 sisting in these very changes of type, the horizontality of the rocks, 

 the deep covering of drift which so generally conceals them, and the 

 interruption of their range from western New York into Ohio, caused 

 by the waters of Lake Erie. 



The direct comparison of the western formation with those of the 

 Appalachian chain being precluded by the changes which the forma- 

 tions undergo in the interval ; it was deemed essential to establish, if 

 possible, their relations by a continuous tracing from Pennsylvania 

 through New York, and thence keeping some easily recognised hori- 

 zon steadily in view, to work round Lake Erie through Upper Canada 

 and Michigan, and by this means form a junction with the strata of 

 Ohio. 



Range of the Niagara Limestone. — In following some of the for- 

 mations of the Niagara River, through Upper Canada, the course of 

 the Niagara limestone, which forms the escarpment of the mountain 

 ridge, was traced westward from Queenstown to the head of Lake 

 Ontario. It then sweeps round the head of the lake, and again 

 changing its strike, takes a N.N.W. direction to the southern end of 

 Lake Iroquois, or Georgian bay of Lake Huron. A section of the 

 formation is then given in the neighbourhood of Ancaster, about fifty 

 miles west of Niagara. It shows a slight change in the lithological 

 character of some of the strata, accompanied by an increase of thick- 

 ness of the general mass as traced westward. 



The Gypsum Shales are then traced in a belt south of the terrace, 

 and shown to intersect the Welland Canal, and to follow the course 

 of Grand River to the vicinity of Paris. From this point they strike 

 north with the mountain ridge, and passing a little east of Guelph, 



