SOME LOCAL DETAILS. 167 



slates pebbly or shingly. The greater number of the 

 stones contained in the drift are usually, like the paste 

 containing them, derived from the neighbouring rock 

 formations. These untravelled fragments are often of 

 large size, and are usually angular, except when they are 

 of very soft material, or of rocks whose corners readily 

 weather away. It is easy to observe, that on passing 

 from a granite district to one composed of slate, or from 

 slate to sandstone, the 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 

 popularly 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. The boulders are, as usual, often glaciated or 

 marked with ice-striae. 



Though the more abundant fragments are 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 has 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. In some of the carboniferous districts where 

 the boulder-clay is thick, as for example, near Pictou 

 harbour, it is as if a gigantic harrow had been dragged 



