1845.] S8S 



ness of primitive or granitic rocks. These rocks, from the northern 

 shores of the two lakes just mentioned, pass close to the northward 

 of Lake Simcoe, and are met with in ascending all the streams 

 tributary to the Rice Lakes, and to Ontario from the north. 

 Sending off a spur to the southward, they are seen at the N. E. 

 extremity of the last-named lake on the immediate shore of the 

 St. Lawrence, which they cross some miles below, forming many 

 of the Thousand Islands, and uniting with the primary region in 

 the northern part of the state of New York. 



From Kingston and the Thousand Islands the primitive beds may 

 be traced to the N.E., until they cross the Ottawa River near 

 Lake Chat. Thence, continuing in the same direction, they form 

 the northern side of the valley of the St. Lawrence, and the rapids 

 and falls a few miles up its ti'ibutary streams, till they abut upon 

 that river at Cape Tourment, nine or ten leagues below Quebec. 

 From the point last designated, the granitic rocks continue with- 

 out interruption to form the northern shore of the St. Lawrence 

 river and gulf to the strait of Belle Isle. 



To the southward of this wild country, inhabited only by fur- 

 traders or scanty bands of roving Indians, succeeds one of com- 

 parative fertility, which it owes principally to the presence of 

 transition rocks, or to the beds of clay and sand that frequently 

 overlie them, and which, in some cases, have been found to belong 

 to the newer pliocene or post-pliocene era. 



The object of the present memoir is to trace very generally, but 

 accurately, as far as it is yet known, the line of junction of the 

 fossiliferous transition strata just alluded to, with the primary 

 rocks on which they repose ; to point out briefly the fossils and 

 minerals which have been found in each ; and to offer such in- 

 ferences as may fairly be drawn from the cursory examination of 

 a region of such wide extent. It is only the rough outline, and so 

 far as regards the northern district, which is here attempted ; the 

 filling up of the picture in all its details, notwithstanding the great 

 progress made by the American geologists, and recently by Mr. 

 Lyell, must be the work of years and of many hands. 



Commencing from the extreme west of the line which has been 

 indicated, the magnificent Lake Superior first claims attention. Re- 

 ferring for a description of its rocks and minerals, as far as they are 

 yet known, to the first volume of the Transactions of the Literary 

 and Historical Society of Quebec, it will be sufiicient here to no- 

 tice very generally its principal geological features. The height of 

 land surrounding this immense lake, and on which its numerous tri- 

 butary streams have their sources at an elevation not exceeding 700 

 feet above the lake, may be considered as forming an irregularly 

 oval basin, and is every where composed of primitive rocks. The 

 highest hills do not rise beyond 2000 feet above the lake, whose sur- 

 face is 623 feet above and its extreme depths perhaps as far below 

 the tidal waters of the Atlantic. Primitive rocks form much of the 

 steep and mountainous north coast, and are also occasionally seen 

 on its southern shore. They consist of various granitic compounds, 



X X 4 



