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



St. Charles five miles from Quebec, we find the Utica slate abutting 

 directly on the Trenton rock in the manner represented in fig. 3. 



R. St. Charles. — The cascade of the St. Charles at Jeune Lorette, 

 eight miles W.N.W. of Quebec, is an interesting spot. Here the 

 river leaps over a ledge of gneiss into a deep gorge, with mural sides 

 for the most part and half a mile long. 



Close to the foot of the cascade, the coarse granular gneiss, faced 

 by water-worn bosses full of cracks, is covered on both banks by 

 Trenton limestone, but not completely on the left behind the Mill. 



Although Potsdam sandstone has not been detected as yet, doubt- 

 less it is near at hand, for angular blocks of the gneiss of the locality 

 lie upon the fixed rock, with a dirty powder about them as at Mont- 

 morenci, but there is not the same pale, friable, calcareous cement. 



Adapting itself and firmly adhering to the inequalities of the gneiss 

 above spoken of, Trenton limestone (in no respect different from that 

 of Montmorenci) enters and fills its deep fissures. A few inches 

 above the gneiss the limestone becomes horizontally stratified, in 

 thicknesses varying from 5 to 18 inches, both at this place and 

 between the mill and the village church. 



On the west bank, close to and below the Falls, the limestone dips 

 gently to the south ; and 1 00 yards further down the gorge, the 

 strata are very massive, and dip to the east * at an angle of 30° ; but 

 they dip to the S.E. in an adjacent field on the west. 



Not many yards below this we come upon the true argillo-calcareous 

 shale of Utica slate, with Graptolites and few or no other fossils, 

 whilst the Trenton beds close at hand are found full of characteristic 

 organic remains. 



Hudson River Group at Quebec, along the N. shore of the St. 

 Lawrence, and South of the St. Lawrence. — We now proceed to 

 notice the black shales, ferruginous clay-slates, sandstones, limestones, 

 and various conglomerates which prevail so enormously on the south 

 of the St, Lawrence, and whose innumerable intercalations show such 

 singularly frequent changes of condition in the sea which deposited 

 them. They are, as before said, the Hudson River Group of the 

 State of New York. 



Their northern boundary near Quebec has been already given. 

 Mr. Loganf states that on the south side of the St. Lawrence, from 

 the river Chaudiere near Quebec to the Temiscouta Road, a distance 

 of about 130 miles, the strata in an ascending series from Trenton 

 limestone and Utica slate, consist of — 



1 . Dark grey clay-slates, sandstones, and limestones ; in very thin 



beds ; fossiliferous, with Graptolites. This division is only seen 

 f on one spot E.S.E. of Quebec, opposite the lower end of the 

 "'■ Island of Orleans, but prevails largely S. W. of Quebec. 



2. Grey, green, and red shales, with bands of thin calcareous con- 



glomerate. 



3. Hard sandstones, grey, greenish, with a little mica. Sometimes 



calcareous conglomerate, with Trenton fossils. 



* Possibly a displacement from local causes. 



t Report on the Geology of Canada, 1849-50, p. 32 andj»««sm. 



