JNotes on the Geology of Murray Bay, 149 



principal terraces at Murray Bay, correspond nearly with two of 

 the principal shore levels at Montreal, as noticed in my former 

 paper on the Post Pliocene deposits,* in which it will be seen 

 that in various parts of Canada, two principal lines of old sea 

 beaches occur at about 100 to 150 feet, and 300 to 350 feet above 

 the sea, though there are others at diflferent levels. To these I 

 have now to add an observation made last summer at Upton, in 

 the Eastern Townships, where I saw in a cleft of the limestone 

 quarried there for copper ore, a deposit of comminuted mussel 

 shells, and entire valves of Tellina Groenlwidica^ Saxicava ru- 

 gQsa, and Mya arenaria, lying just as the surf drove them into 

 the fissures of this old reef, when th-e sea stood more than 300 

 feet above its present level. Guyot remarks in his late paper on 

 the Appalachian mountain system,f that a depression of 140 feet 

 would convert the whole of New England, and the eastern part 

 of Lower Canada into an island ; so that when the sea stood at the 

 level of this highest beach at Murray Bay, the hills of New Eng- 

 land, of the Eastern Townships, and of Gasp^, formed a long 

 rocky island, separated from the similar masses of hills to the 

 west and south-west, by straits 30 fathoms deep, and all the plain 

 of the St. Lawrence was a sea with but a fevr rocky islets pro- 

 jecting from it here and there. These stupendous changes be- 

 long to the later geological history of Canada, and its re-eleva- 

 tion into dry land belongs to the beginning of the modern period 

 of geology. In the valley of the Murray Bay River, there are 

 evidences of less important but interesting processes attending 

 this re-elevation of the land. 



In the Pleistocene period the valley of the river has been filled, 

 almost or quite to the level of the highest terrace, with an en- 

 ormously thick mass of mud and boulders, washed from the land 

 and deposited in the sea bed during the long periods of 

 newer Pliocene and Pleistocene submergence. Through this 

 mass the deep valley of the river has been cut, and the 

 clay, deprived of support and resting on inclined surfaces, has 

 slipped downward, forming strangely shaped shelves, and outly- 

 ing masses, that have in some instances been moulded by the re- 

 ceding waves, or by the subsequent action of the weather, into 

 conical mounds, so regular that it is difficult to convince many of 

 the visitors to the bay that they are not artificial. Sir W. E. 



* Canadian Naturalist, Vol. 11. 

 t Sillimaji's Journal. 



