go THE POST-PLIOCENE PERIOD. 



tte character of the loose stones changes accordingly. It is also a 

 matter of familiar observation, that in proportion to the hardness or 

 softness of the prevailing rocks, the quantity of these loose stones 

 increases or diminishes. In some of the quartzite and granite districts 

 of the Atlantic coast, the surface seems to be heaped with boulders 

 with only a little soil in their interstices, and every little field, cleared 

 with immense labour, is still half-filled with huge white masses popu- 

 larly known as " elephants." On the other hand, in the districts of 

 soft sandstone and shale, one may travel some distance without seeing 

 a boulder of considerable size. 



Though I have called these fragments untravelled, it by no means 

 follows that they are undisturbed. They have been lifted from their 

 original beds, heaped upon each other in every variety of position, and 

 intermixed with sand and clay, in a manner which shows convincingly 

 that the sorting action of running water had nothing to do with the 

 matter ; and this applies not only to stones of moderate size, but to 

 masses of ten feet or more in diameter. It is as if a gigantic harrow 

 had been dragged over the surface, tearing up the solid rocks, and 

 mingling their fragments in a rude and unsorted mass. 



Beside the untravelled fragments, the drift always contains boulders 

 derived from distant localities, to which in many cases we can trace 

 them ; and I shall mention a few instances of this to show how ex- 

 tensive has been this transport of detritus. In the low country of 

 Cumberland there are few boulders, but of the few that appear, some 

 belong to the hard rocks of the Cobequid Hills to the southward; others 

 may have been derived from the somewhat similar hills of New 

 Brunswick. On the summits of the Cobequid Hills and their northern 

 slopes, we find angular fragments of the sandstones of the plain below, 

 not only drifted from their original sites, but elevated several hundreds 

 of feet above them. To the southward and eastward of the Cobequids, 

 throughout Colchester, Northern Hants, and Pictou, fragments from 

 these hills, usually much rounded, are the most abundant travelled 

 boulders, showing that there has been great driftage from this elevated 

 tract. In like manner, the long ridge of trap rocks extending from 

 Cape Blomidon to Briar Island has sent off great quantities of boulders 

 across the sandstone valley which bounds it on the south, and up the 

 slopes of the slate and granite hills to the southward of this valley. 

 Well characterized fragments of trap from Blomidon may be seen 

 near the town of Windsor ; and I have seen unmistakable fragments 

 of similar rock from Digby Neck, on the Tusket River, thirty miles 

 from their original position. On the other hand, numerous boulders 

 of granite have been carried to the northward from the hills of 



