286 DENUDATION OF THE LAND. Chap. VI. 



boulder-clay and moraine rubbish. Nor, as 

 far as I could judge, was the formation of 

 these little cliffs at all closely connected with 

 the trampling of cows or sheep. It appeared 

 as if the whole superficial, somewhat argil- 

 laceous earth, while partially held together 

 by the roots of the grasses, had slided a little 

 way down the mountain sides; and in thus 

 sliding, had yielded and cracked in horizontal 

 lines, transversely to the slope. 



Castings blown to leeward by the wind, — We 

 have seen that moist castings flow, and that 

 disintegrated castings roll down any inclined 

 surface ; and we shall now see that castings, 

 recently ejected on level grass-covered 

 surfaces, are blown during gales of wind ac- 

 companied by rain to leeward. This has been 

 observed by me many times on" many fields 

 during several successive years. After such 

 gales, the castings present a gently inclined 

 and smooth, or sometimes furrowed, surface 

 to windward, while they are steeply inclined 

 or precipitous to leeward, so that they resem- 

 ble on a miniature scale glacier-ground hillocks 

 of rock. . They are often cavernous on the 



