SOME LOCAL DETAILS. 165 



sub-marine and not a sub-aerial deposit, seems to be 

 rendered probable by the circumstance that many of the 

 boulders of sandstone are so soft that they crumble 

 immediately when exposed to the weather and frost. 



The travelled boulders lying on the surface of the 

 boulder-clay evidently belong to a later period, when the 

 hills of Labrador arid Nova Scotia were above water, 

 though lower than at present, and were sufficiently bare 

 to furnish large supplies of stones to coast-ice carried by 

 the tidal currents sweeping up the coast, or by the arctic 

 current from the north, and deposited on the surface of 

 Prince Edward Island, then a shallow sand-bank. The 

 sands with sea shells probably belonged to this period, or 

 perhaps to the later part of it, when the land was 

 gradually rising. Prince Edward Island thus appears to 

 have received boulders from both sides of the gulf of St. 

 Lawrence during the later Pleistocene period; but the 

 greater number from the south side, perhaps because 

 nearer to it. It thus furnishes a remarkable illustration 

 of the transport of travelled stones at this period in 

 different directions, and in the comparative absence of 

 travelled stones in the lower boulder-clay, it furnishes a 

 similar illustration of the homogeneous and untravelled 

 character of that deposit, in circumstances where the 

 theory of floating ice serves to account for it, at least as 

 well as that of land-ice, and in my judgment, greatly 

 better. 



In these respects the Pleistocene of Prince Edward 

 Island bears considerable resemblance to that of the lower 

 grounds of Nova Scotia, where local material is prevalent 

 in the lower part of the deposit, and travelled boulders 

 from different directions occur in the upper bed. 



