264 Dr. Bigsby's Sketch of the Topography 



All the portions with which we are now concerned seem to 

 be contemporaneous ; judging from their mutual conformable- 

 ness, similarity of position, and from their containing the same 

 characteristic minerals at distant intervals (schorl and mag- 

 netic ii'on ore). Like the older formations of Lakes Superior 

 and Huron, I believe these to be the more recent of their class, 



A line drawn E.S.E. from Penetanguishene (N.E. coast of 

 Lake Huron) to Kingston on Lake Ontario, will represent 

 with tolerable accuracy its southern limits so far. It is con- 

 tinued thence, nearly in the same dii'ection, twelve miles down 

 the outlet* ; when suddenly an irregular S.S.E. or S.E. course 

 is assumed to " Little Falls"on the Mohawk, twenty-six miles 

 eastof Utica. The connection between these ancient rocks in 

 the neighbourhood of Lake Ontario, and those of Labrador 

 and the northern dividing ridge of the valley of the St. Law- 

 rence, has been satisfactorily established by tracing them 

 up the Gananoque River to the townships of Perth, Lan- 

 ark, &c. to the Lake and River Mississippi, which falls into 

 the Ottawa at the lower end of its expansion called Lake Chat, 

 and close to the southern limit of primitive X'ocks on that river. 

 Setting out from Marmora, a township sixty miles W.N.W. 

 from Kingston, Mr. Smilhf in 1823 ascended through a pri- 

 mitive country to the same river Mississippi, by Crow Lake, 

 Belmont River and Lake, and other water-courses. 



In the interval between Lake Huron and Kingston, above 

 referred to, consisting chiefly of lakes, woods and morasses, 

 little more is known of this primitive range than its existence. 

 Captain Macaulay, R.E. informed me that it lines the north- 

 east shore of Lake Simcoe. It is gneiss there, apparently. 

 Between that lake and Crow Lake| near the River Trent^ 

 I am informed that horizontal limestone advances from Lake 

 Ontario fully to the boundary I have assumed ; which, I may now 

 add, just includes the marble and sienite of Crow Lake. This 

 locality I have visited, and found to be composed of the above 

 two rocks, interspersed with large beds ofgranular magnetic iron 

 ore. On the river side, close to the Marmora Iron-works, I saw 

 them in irregular contact, but much weathered. I could in 

 no place discover stratification in either, excepting a doubtful 

 W.S. W. dii'ection in the i*idges of sienite. The marble is in 



* The large islands " Howe" and " Long," almost altogether wood and 

 marsh, I believe to be of intermediary limestone. If they contain many 

 gneiss mounds.the change in the course of the line drawn in the text will be 

 less abrupt. 



+ One of the superintendants of Mr. Hayes's Iron-works at that place. 



X Twenty-seven miles north from Lake Ontario, and about sixty from 

 Kingston. 



round 



