294 DENUDATION OF TEE LAND. Chap. VI. 



on the crowns ; but this would naturally 

 follow from the finer earth having been 

 washed from the crowns into the furrows 

 before the land was well clothed with turf; 

 and it is impossible to tell what part worms 

 may have played in the work. Nevertheless 

 from what we have seen, castings would 

 certainly tend to flow and to be washed during 

 heavy rain from the crowns into the furrows. 

 But as soon as a bed of fine earth had by any 

 means been accumulated in the furrows, it 

 would be more 'favourable for worms than the 

 other parts, and a greater number of castings 

 would be thrown up here than elsewhere ; and 

 as the furrows on sloping land are usually 

 directed so as to carry off the surface water, 

 some of the finest- earth would be washed 

 from the castings which had been here ejected 

 and be carried completely away. The result 

 would be that the furrows would be filled 

 up very slowly, while the crowns would be 

 lowered perhaps still more slowly by the 

 flowing and rolling of the' castings down 

 their gentle inclinations into the furrows. 



Nevertheless it might be expected that old 

 furrows, especially those on a sloping surface, 



