82 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 23, 



2. On the Geology o/ Quebec and its Environs. 

 By J. J. BiGSBY, M.D., F.G.S., Mem. Amer. Phil. Soc. Philadelphia. 



[Plate VI.] 



Quebec, with its environs, presents an instructive field of investi- 

 gation to the geological student in its abundance of natural sections 

 of the earlier palseozoic strata, and particularly in its ample develop- 

 ment of the " Hudson River Group" of the State of New York. 

 We have here also very interesting deposits of the glacial period * ; but 

 of them I shall not speak in this paper — having little to add to the 

 statements of Sir Charles Lyell, Prof. Emmons f, and Capt. Bayfield. 



Topography. — The city and fortress of Quebec crown the lofty 

 bluff at the N.E. end of an elevated tract, that, rising like an island 

 (which once it was), a few hundred feet above the general surface, 

 forms the north shore of the River St. Lawrence for 7^ miles south- 

 westwards (up-stream). 



This tract is rather narrow, and is highest in the middle and about 

 Quebec. Its gentle undulations are covered with woods and farms. 

 While on the N.W. it dips by short ledges and grassy steeps into 

 low meadows a mile or more broad, to ascend again by earthy shelves 

 into the neighbouring mountains ; its S.E. flank consists of rocky 

 cliffs and slopes, varying from 50 to 370 feet in height, and over- 

 looking the St. Lawrence. The Upper Tovrn of Quebec stands on 

 the bluff just mentioned, and the Lower Town, at its base, on made 

 ground, being 240 yards in greatest breadth in Rue sous la Fort. 



The military works enclosing the Upper Town are about 2f miles 

 in circumference ; their principal face being S.W. towards the Plains 

 of Abraham. 



Cape Diamond rises higher than any other part of the bluff or 

 promontory by .^0 or 60 feet, and overlooks a contracted part of the 

 St. Lawrence from an elevation of 372 feet. It is absolutely per- 

 pendicular in most places, and bare. From the highest parts of this 

 Cape, the ground on which the Upper Town stands shelves gently 

 downwards towards the N.W., as far as a steep called " Coteau de 

 Genevieve," where a nearly perpendicular descent takes place of more 

 than 100 feet. 



The picturesque headland nearly opposite to Cape Diamond on the 

 south side of the River St. Lawrence is Point Levi. For 200 feet 

 from the level of the beach it is a shattered cliff, and then rises as 

 high as Cape Diamond in a grassy slope. 



From Point Levi downwards, for fourteen miles, high cliffs prevail 

 along the south bank of the river ; but the opposite or north bank 

 is in taluses and broken steeps. 



The country south of the St. Lawrence maintains for many miles 

 in all directions the elevation observed at Point Levi. It is a rough 

 undulating plain of woods and farms, traversed at intervals by low 

 ridges of almost naked rock. 



* In the accompanying map the extent of the glacial deposits is approximately 

 defined, from my own observations. 



t Emmons, Geology of New York State, p. 128. 



