On the Agricultural Geology of England a 



friable by the fragments of chalk broug^lit ' 

 up by the plough, he considers that they 

 would form a thin, tough, and cold clay. 



4. A tough red clay with flints, lying 

 on the flat summits of the Downs above 

 Reigate, and south of a bed of ferrugi- 

 nous sand, without any chalk, which, by 

 the description given of it, appears to be 

 a small outlier of the sands of the plastic 

 series- 



5. Soils composed exclusively of chalk 

 or rubbly chalk, very slightly covered 

 with earth, are confined to the southern 

 escarpment of the Downs. When the ^ 

 hills are very abrupt, the chalk rises ^ 

 completely to the surface ; and it is re- , 

 marked that a greater extent of such soil ^, 

 is exhibited there, under arable culture, ^ 

 than in any other part of the kingdom. ^ 



On a general review of the soils on the 

 whole of the chalk range, as described by | 

 agricultural writers, we find large tracts 

 of it covered with every variety of soil — Z 

 from sand to clay, from fertile to unpro- | ^ 

 ductive — and no mention of white soils S " 

 till we reach Cambridgeshire. Thence, ?3 g 

 through the remainder of the district, they ^ 

 are partially distributed, being confined 

 to the heads of valleys, to steep escarp- ^ 

 ments, and to the loftiest sum^mits. The 

 varieties of non-calcareous soils on the § 

 chalk appear from the descriptions to be ^ 

 no less dependent than the white soils on ':S 

 contours. We refer them to aqueous 

 action of some kind or other, by which s 

 matter extraneous to the chalk has been '-g 

 spread over its surface by such action at ^ 

 the close of the tertiary era. Those 

 geologists who have adopted the opinion 

 that soils are derived exclusively from 

 the rocks on which they rest, and that 

 they are the result of ordinary atmos- 

 pheric action, find the soils on the chalk 

 a great stumbling-block. They escape it 

 "by supposing that the loam, clay, sand, 

 and angular flints have been derived from 



