No. 2.] DAWSON — POST-PLIOCENE. 185 



These shells imply a higher beach than that of this lower flat, 

 which is not more than 30 feet above the present sea level. Ac- 

 cordingly above this are several higher terraces, the heights of 

 which on the west side of bay are given in Section I. The 

 second principal terrace, which forms a steep bank of clay some 

 distance behind the main road, is 116 feet in height, and is of 

 considerable breadth, and has on its front in some places an im- 

 perfect terrace at the height of 81 feet. It corresponds nearly 

 in height with the shoulder over which the road from the pier 

 passes. Upon it, in the rear of the property of Mr. Du Berger? 

 is a little stream which disappears under ground, probably in a 

 fissure of the underlying limestone, and returns to the surface 

 only on the shore of the bay. Above this is a smaller and less 

 distinct terrace 139 feet high. Beyond this the ground rises in 

 a steep slope, which in many places consists of calcareous beds, 

 worn and abraded by the waves, but showing no distinct terrace ; 

 and the highest distinct shore mark which I observed, is a narrow 

 beach of rounded pebbles at the heifiht of more than 300 feet ; but 

 above this there is a flat at the heioht of 448 feet. This beach 

 appears to become a wide terrace further to the North, and also 

 on the opposite side of the bay. It probably corresponds with the 

 highest terrace observed by Sir W. E. Logan, at Bay St. Paul, 

 and estimated by him at the height of 360 feet. 



As already stated, three of the principal terraces at Murray 

 Bay correspond nearly with three of the principal shore levels at 

 Montreal ; and 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 different levels. 



In the Post-pliocene period the valley of the Murray Bay river 

 has been filled, almost or quite to the level of the highest terrace, 

 witli an enormously thick mass of mud and boulders, washed 

 from the land and deposited in the sea bed during the long period 

 of Post-pliocene submergence. Through this mass the deep val- 

 ley of the river has been cut, and the clay, deprived of support 

 and resting on inclined surfaces, has slipped downward, forming 

 strangely shaped slopes, and outlying masses, that have in some 

 instances been moulded by the receding waves, or by the subse- 

 quent 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. Logan in his report on the district 

 has in my view given the true explanation of these mounds, which 



