249 



Lorraine Shales or Hudson River Group. — Mr. Logan, in his section 

 from Montmorency to the Island of Orleans, regards the bed of the 

 St. Lawrence as entirely formed by dark gray shales and sandstones, 

 which he considers of the age of the Hudson River group. Having 

 no diving apparatus at my disposition, I was unable to follow him to 

 the bottom of the St. Lawrence. If this group really exists in the 

 vicinity of Quebec, it will be brought out by a careful examination 

 of all the strata between Ste. Foix and Indian Lorette. 



Uiica Slates. — Dr. Emmons, in his Geology of New YorJc, 1842, p. 

 117, refers the slates of Montmorency Falls to the Utica Slates, having 

 found there the characteristic Trilobites of Triartkus BecJcii. Dr. 

 Bigsby also calls them Utica slates (On the Geology of Quebec and its 

 environs, 1853), and so did, after their example, Mr. Logan. In my 

 short exploration of 1849, I erroneously considered those black slates 

 of Montmorency Falls as older than the Trenton Limestone forming 

 the summit of the falls ; but at my recent visit I found the opinion of 

 the geologist above named to be correct. 



Trenton Limestone. — The thirty feet of limestone at the top of Mont- 

 morency Falls, and at the foot of the precipice immediately in contact 

 with the quartzite, are of the Trenton Limestone age, as Mr. Logan has 

 stated in his description of Montmorency formations ; fossils are very 

 abundant in both places. 



Black River Group. — I was unable to refer any strata to the subdi- 

 visions of this group. Mr. Logan does not give any special localities 

 for it, having only put it in his diagram and theoretical section without 

 other notice. 



Calciferous Sandstone. — This group is composed, at the summit, of 

 blue schistose marls, interstratified with thin bedded limestones, blue 

 and sometimes almost black, and large masses of conglomerate, the size 

 of the rounded pebble attaining even that of the true boulder. In this 

 tipper part, especially in the cliiF on the road from the ferry to Notre 

 Dame church at Point Levi, are found a quantity of the celebrated 

 compound Graptolidce. The citadel and the old town of Quebec are 

 built on it. Then there is a succession of gray slates, sometimes 

 almost black, with alternations of yellowish coarse sandstone, magne- 

 sian conglomerate, and twenty or thirty feet of a gray limestone, brec- 

 ciated, hard, and very fossiliferous. I did not see the lower part of 

 the Calciferous Sandstone ; perhaps it has been concealed by the dislo- 

 cations, or was never deposited in this part of Canada. The thick- 

 ness of the whole is about six hundred feet. This number appears at 

 first a small one, but if we take into consideration the numerous fold- 

 ings of this deposit, and also the narrow band it forms, it will be seen 

 to be sufficient, for the ridge which it forms is never more than a mile 

 and a half in width, extending from Quebec to the Plains of Abra- 



