CHAP. IV.] THE VOYAGE HOME. 215 



direction of its line of descent. These movements are proba- 

 bly extremely slow. I well remember many years ago observ- 

 ing a case, somewhere in the West of Scotland, where a stream 

 had exposed a fine section of the soil -cap with the lines of 

 broken-down and crushed slate-beds carried far down the slope. 

 The whole effect was so graphically one of vigorous and irre- 

 sistible movement, that I examined carefully some cottages and 

 old trees in hope of finding some evidence of twisting or other 

 irregular dislocations ; but there appeared to be none such. 

 The movement, if it were sufficiently rajiid to make a sign dur- 

 ing the life of a cottage or a tree, evidently pervaded the whole 

 mass uniformly. 



It seems to me almost self-evident that wherever there is a 

 slope, be it ever so gentle, the soil-cap must be in motion, be 

 the motion ever so slow ; and that it is dragging over the sur- 

 face of the rock beneath the l)locks and bowlders which may 

 be imbedded in it ; and frequently piling these in moraine-like 

 masses, where the progress of the earth-glacier is particularly 

 arrested, as at the contracted mouth of a valley, where the 

 water percolating through among them in time removes the 

 intervening soil. As the avalanche is the catastrophe of ice- 

 movement, so the land-slip is the catastrophe of the movement 

 of the soil-cap. 



As I have already said, I should be the last to iTndervalue the 

 action of ice, or to doubt the abundant evidences of glacial ac- 

 tion ; but of this I feel convinced, that too little attention has 

 been hitherto given to this parallel series of phenomena, which 

 in many cases it will be found very difficult to discriminate; 

 and that these phenomena must be carefully distinguished and 

 discriminated before we can fully accept the grooving of rocks 

 and the accumulation of moraines as complete evidence of a 

 former existence of glacial conditions. 



On the 1st of February we went round to the head of Berke- 

 ley Sound, and saw the old station of St. Louis now nearly de- 



