G. W. Robinson 381 



The results present several points of interest. Hendrick and Ogg^ 

 have recently studied the fractions of a Scottish drift soil consisting 

 mainly of local granite and metamorphic material. The soils examined 

 by the writer present many points of similarity to the Craibstone soil 

 and may be contrasted with the English soils submitted to fractional 

 analysis by Hall and Russell^. 



For the sake of comparison the results for the Craibstone and 

 English soils respectively are reproduced in the following table : 



Percentages of 



The soils examined by the writer agree with the Craibstone soil in 

 being poorer in silica and richer in alumina and ferric oxide in the 

 various fractions. In the Welsh soils however the silica percentages in 

 the coarser fractions are even lower than the silica percentages in the 

 Craibstone soils. The proportion of alumina and ferric oxide are also 

 higher. The most notable difference however is that in the Welsh soils 

 the most siliceous fraction is never the fine gravel as in the Craibstone 

 and English soils. It will be seen that the highest percentage of silica 

 is found in the coarse sand in four cases, in the fine sand in three cases 

 and in the silt three cases. 



If we take the average silica percentage in the fine gravel of those 

 soils in which the highest silica percentage is found in the coarse sand, 

 we shall find it to be greater than the corresponding percentage for those 

 soils in which the fine sand is the most siliceous fraction. And similarly 

 the soils in which the fine sand is the most siliceous fraction have a 

 more siliceous fine gravel than the soils in which the highest silica 

 content is in the silt. The following table will illustrate this: 



This Journal, vol. vn, pp. 458-469. - This Joiirval, vol. iv, pp. 181-223. 



