128 Sir IT. H. Howorth — Erratic Boulders in Drift. 



polish and smooth the different facets as well as the angles. This 

 rounding and smoothing and blunting of angles have always been 

 attributed to water, and I take it that conclusion is generally held 

 stiU.i 



Now the remarkable part about the boulders in the surface beds 

 of Eastern England, those of local origin as well as the foreigners, is 

 that they are all either subangular or rounded. The true glacier type 

 of skidded flat stone, I have never seen there, nor have I seen 

 specimens of those enormous sharp-edged erratics which have never 

 left the glacier's back until they were finally laid to rest. The only 

 large blocks are the local ones, while the far-travelled foreigners are 

 not onlj' small in size, but greatly rounded and worn, while those 

 which have travelled less have their angles still preserved, 

 but they are blunted and rubbed down by rolling into subangular 

 forms. This, so far as I know, is universal. How, then, can we 

 attribute these boulders to ice-portage ? If they had come on the 

 back of the glacier they should be completely sharp and fresh, and 

 we ought to have a great many of them of very large size indeed, 

 especially the crystalline boulders. A mass of ice can carry a load as 

 big as a house just as well as a pebble, but the crystalline boulders are 

 nearly all small. It is only the local rocks that occur in fairly 

 large masses. Nor, again, ought they (as they are) to be sorted 

 roughly according to their size, so that we find them as a whole 

 diminishing in size as we get away from their source. This is not 

 the fashion with ice-portage at all, as a very casual visit to a living 

 glacier and a living moraine will prove. There the biggest stones 

 are often found in the most remote moraines, having travelled the 

 furthest. But we are told these stones are sometimes scratched, and 

 in the case of the soft stones not infrequently scratched, and that 

 must surely be due to ice. So they are scratched. The absurdity 

 to me is the conclusion that the majority of these scratches were 

 made in any way by ice, or that ice could possibly have had a part in 

 the work. Let us look a little more closely than is usually done by 

 those who cling to ice, as a drowning man is said to cling to 

 a straw, without ever considering its actual handiwork. 



When ice first enters a valley with rough and torn edges to its 

 rocks, it proceeds no doubt to rub these rough places down and 

 to smooth them, and to remove the parts that cause friction until 

 it creates for itself a smooth and jjolished bed as a river does. 

 The result of this action is the pouring out at its foot of a 

 considerable quantity of mealy water. This part of the work is, 

 however, presently finished, and, except where the slope is great 



[' It is well to bear in mind the intimate connection between ice and water-action 

 going on in a glacier. Thus, in summer the runlets of water, which form upon the 

 surface of the ice, gradually form streams which fall down some crevasse through 

 the ice to the bed of the glacier, and, acting with a gyratory motion upon the 

 angular stones and gravel, may produce not only hollows in the floor of 

 the glacier, but also rounded boulders, often of considerable size. These in 

 time find their way down the ice-stream to the terminal moraine of the glacier. 

 Thus it is often difficult to separate the action of ice from that of water in such 

 cases. — Edit.] 



