Chap. VI. AIDED BY WORMS. 275 



about 100 inches of rain fall) into the little 

 water-course, and thence into the plains 

 lying below at a depth of 3000 or 4000 feet. 



Castings ejected before or during dry 

 weather become hard, sometimes surprisingly 

 hard_, from the particles of earth having been 

 cemented together by the intestinal secre- 

 tions. Frost seems to be less effective in 

 their disintegration than might have been 

 expected. Nevertheless they readily disin- 

 tegrate into small pellets, after being alter- 

 nately moistened with rain and again dried. 

 Those which have flowed during rain down a 

 slope, disintegrate in the same manner. Such 

 pellets often roll a little down any sloping 

 surface ; their descent being sometimes much 

 aided by the wind. The whole bottom of a 

 broad dry ditch in my grounds, where there 

 were very few fresh castings, was completely 

 covered with these pellets or disintegrated 

 castings, which had rolled down the steep 

 sides, inclined at an angle of 27°. 



Near Nice, in places where the great cylin- 

 drical castings, previously described, abound, 

 the soil consists of very fine arenaceo-cal- 

 careous loam ; and Dr. King informs me that 



