T. RiGG 389 



(4) Boulder clay giving rise to three soil formations: 



(a) Pure boulder clay soil, 



(6) Heavy loam produced by wash on boulder clay, 

 (c) Sandy loam produced by a thin capping of boulder 

 clay on greensand. 



(5) Brick earths giving rise to only one soil formation. 



(6) Glacial giving rise to one soil formation, which, however, is 

 not quite so uniform as the brick earth formation. 



(7) Valley gravels giving rise to three soil formations: 



(a) A brown soil formation (referred to as ''Old 



Brown"), 

 (6) A heavy brown soil formation, 

 (c) A more recent dark soil formation (referred to as "New 



Dark"). 



Samples of soil from each soil formation were then collected and 

 submitted to chemical and mechanical analysis using the methods 

 adopted by the Agricultural Education Association i. 



By this means, not only was it possible to verify the field observations 

 in referring soils to distinct soil formations, but the soil formations were 

 thus defined by a conventional method which admitted comparison 

 of the soils with those of other parts of England and foreign countries. 

 A glance at the results of analysis in the Appendix will show that not 

 only has mechanical and chemical analysis differentiated between the 

 various soil formations but an extraordinary uniformity between the 

 samples taken from any soil formation is revealed, e.g. the greensand 

 soils. This series of soils is differentiated from any other by the low 

 percentage of potash and mineral salts and an almost entire absence 

 of calcium carbonate. The coarse sand fraction is particularly high 

 and this fact alone would be almost sufficient to distinguish it from 

 any other series. 



The uniformity of the samples collected from different parts 

 of a soil formation is well illustrated in the case of these soils. 

 In five soils from the brown sands the following variations were 

 found : — 



