SOLIFLUCTION 



95 



circular walls composed of rock fragments and including a patch 

 of muddy material, often hardened through desiccation. Evidently 

 all these phenomena only represent different fades of the displace- 

 ment of the waste. 



It is not very difficult to find out the mode of formation of 

 the "mud-glaciers" mentioned above. When in summer time the 

 melting of the snow has reached an advanced stage, often the bot- 



FiG. 2. — Scenery from the southern part of Bear Island, showing the contrast 

 between the rounded land-forms caused by subaerial denudation and the perpen- 

 dicular coastal cliffs caused by marine abrasion, dissecting the island. 



tom of the valleys are free from snow, while big masses still rest in 

 sheltered places on the valley sides. Every warm and sunny day 

 new quantities of water trickle from these melting drifts into the 

 rock-waste at their lower edge. As the masses of detritus are com- 

 posed not only of coarser rock fragments such as blocks, slabs, and 

 gravel, but also of finer particles filhng the interspaces between the 

 coarser material, they are able to absorb considerable quantities 

 of water. When once saturated, they form a semifluid substance 

 that starts moving slowly down-hill. This process, the slow 

 flowing from higher to lower ground of masses of waste satu- 

 rated with water (this may come from snow-melting or rain), I 



