CAMBRIAN ROCKS OF NOVA SCOTIA. — POOLE. 241 



There are two typical exposures iu this neighborhood 

 worthy of close study. One is made by the railway cut- 

 ting at the entrance of North street station, and the other is 

 across the harbor on the Dartmouth shore opposite the Dock- 

 yard. Both clearly show weathered slate ridges rising up 

 shattered and settling to blend with the breccia filling the 

 intervening fissures. 



The Halifax conglomerate occurs at the Imperial wharf at 

 Ferguson's Cove and northward in spots to the last exposure of 

 rocks near Purcell's Cove ; on the west side of the North West 

 Arm about Melville Island ; on both sides at the head of the 

 Arm, and half way up the hill on the side of tlie road to 

 Chain Lakes. Again on the Dutch Village road near the Three 

 Mile House ; in the railway cutting out of North Street station, 

 and on the shore of the harbor north of the sugar refinery at 

 Richmond. At the latter spot the conglomerate is twelve or 

 more feet thick and is seen to rest on a smoothed and much 

 striated surface of slate. At a greater elevation in the railway 

 cutting mentioned, the glacial abrasion has not removed the 

 previously weathered and shattered rock surface of a preceding 

 age, and a cemented breccia occupies the ancient runlets and 

 V-shaped channels in the weathered slates identical with the 

 exposure of the conglomerate at sea level on the opposite Dart- 

 mouth shore. When one considers the durability of the slate,'^* 

 and the very slight decomposition it has undergone on the 

 uncovered glaciated knolls., and then note the great depth in 

 these rocks to which the pre-glacial weathering extended before 

 the deposition of the conglomerate, one is forced to extend an 

 extreme age to the pre-conglomerote cycle of exposure. 



The student of glacial phenomena will be interested in 

 noting in the drift composing the islands of Purcell's Cove, 

 transported blocks of this conglomerate indicating the comple- 



(1) The durability of the slate of this region is well illustrated by the tombstones 

 made of it and set up one hundred and thirty years ago, They show the light lines 

 scratched for the guidance of the sculptor as sharp as though made recently. 



