SOME LOCAL DETAILS. 163 



may be stated in general terms that the majority are 

 granite, syenite, diorite, felsite, porphyry, quartzite and 

 coarse slates, all identical in mineral character with those 

 which occur in the metamorphic districts of Nova Scotia 

 and New Brunswick, at distances of from 50 to 200 miles 

 to the south and south-west ; though some of them may 

 have been derived from Cape Breton on the east. It is 

 further to be observed that these boulders are most abund- 

 ant and the evidences of denudation of the Trias greatest 

 in that part of the island which is opposite the deep break 

 between the hills of Nova Scotia and New Brunswick, 

 occupied by the bay of Fundy, Chignecto bay and the low 

 country extending thence to baie Verte and Northumber- 

 land strait, an evidence that this boulder-drift was con- 

 nected with currents of water passing up this depression 

 from the south or south-west during, perhaps, the later 

 part of the Pleistocene.* 



Besides these boulders, however, there are others of a 

 different character; such as gneiss, hornblende schist, 

 anorthosite and Labradorite rock, which must have been 

 derived from the Laurentian rocks of Labrador and 

 Canada, distant 250 miles or more, to the northward. 

 These Laurentian rocks are chiefly found on the north 

 side of the island, as if at the time of their arrival the 

 island formed a shoal, at the north side of which the ice 

 carrying the boulders grounded and melted away. With 

 reference to these boulders, it is to be observed that a 

 depression of four or five hundred feet would open a clear 

 passage for the arctic current entering the straits of 



* I am informed that Mr. Chalmers has discovered striae on the 

 rocks of this low isthmus, which would show the passage of heavy ice 

 through it in Pleistocene times. 



