Chap. III. BROUGHT UP BY WORMS. 131 



cinders had been strewed, only about half-a- 

 year before, and these either still lay on the 

 surface or were entangled among the roots of 

 the grasses ; and I here saw the commence- 

 ment of the burying process, for worm-cast- 

 ings had been heaped on several of the 

 smaller fragments. After an interval of 

 4| years this field was re-examined, and now 

 the two layers of lime and cinders were found 

 almost everywhere at a greater depth than 

 before by nearly 1 inch, we will say by of 

 an inch. Therefore mould to an average 

 thickness of '22 of an inch had been annually 

 brought up by the worms, and had been 

 spread over the surface of this field. 



Coal-cinders had been strewed over another 

 field, at a date which could not be positively 

 ascertained, so thickly that they formed 

 (October, 1837) a layer, 1 inch in thickness 

 at a depth of about 3 inches from the surface. 

 The layer was so continuous that the over- 

 lying dark vegetable mould was connected 

 with the sub-soil of red clay only by the roots 

 of the grasses ; and when these were broken, 

 the mould and the red clay fell apart. In a 



third field, on which coal-cinders and burnt 



7 



