SOMK LOCAL DKTAILS. 1G7 



sliites ]»ultlily <»i' sliiiiii'ly. 'I'lic greater numlier of tlie 

 stuiies coiiiaiiu'il in ilic diit'l ai'c usually, like llu' jiaste 

 coiitainiu}^' tlieni, derivt'd IVoui tlic ueiuliliouriui;- vovk 

 formations, 'riicsc unlravelled t'rai^nienis arc (tflen of 

 lai'ue size, and ari' usually anu'ular, ('xcciii wiu'u lliov are 

 of very soft material, or of rocks nvIiosc corners readily 

 weather away. It is easy to oliser\e, thai on ]»assin^' 

 from a ,Li;raiiite district to oiu' con:j)osc(l of slate, or from 

 slate to sandstone, the character of the loose stones 

 clian^L;'(^s accordingly. It is also a matter of familiar 

 observation, that in jiroportion to ilm hardness or softness 

 of the ja'evailini.^' rocks, the ([uantity of these loose stones 

 iuereases or diminishes. In some of the (juartzite and 

 «,a'anite districts of the Atlantic coast, the surface seems 

 to be heajxid with boulders with only a little soil in their 

 interstices, ami every little li(dil, cleared with immense 

 labour, is still half tilled with huj^e white masses 

 liO])ularly known as " elejihants." ( )ii the other haml, 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 glaeiated 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 

 w"ith 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 sonm of the carboniferous districts where 

 tlie boulder-clay is thick, as for example, near Pictoii 

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



