19 



'deutscbo geologische gesellscliafit'). I liavc liad many opportunities when sxir- 

 veying and mapping in the Province of Braudenhurg, Germany, to observe the 

 coiTectness of this theory. In many instances only an upper layer, of irregular 

 extent, and limited by an undulating line at a little distance from the surface of 

 the soil, has lost its lime; but in some other instances, where the thickness of the 

 marly soil was not very great, and where sands or conglomerates pendous to 

 water were imderlying it, it is seen to be completely deprived of lime. 



It needs scarcely be added that the loess is very often subjected to the same 

 law and very often has, in its su[>erficial parts, lost that higher ]>ercentage of 

 lime which is always found in normal loess. Now nioreover we find in such soils, 

 out of which the lime has been washed by the atmospheric water, a certain degree 

 of accumulation of clay in the lower and a comparatively small amount of it in 

 the upper part. This, of course, is also quite natural, as, in the process of out- 

 washing, the soil becomes loose and the clay can also be washed out of it to a 

 certain degree, and thus carried down and, in jnany instances, accumulated in the 

 lower part of the outwashed soil. In other cases it may be even taken down into 

 loose sands &c. imderlying the smaller layers of marly and afterwards loamy soil. 



That the sandy clayish soil of the upper part of the diluvial formation of 

 the Tokio plain has no lime and a higher percentage of clay than other soils of 

 an analogous origin and of the same geological age, cannot be surprising, even if 

 we do not take into consideration that all the true loess, at least that of Europe, 

 has been derived from rocks worn and ground liy glacier action. 



Kocks thus reduced to powder would be much less exposed to loss than 

 rocks converted into detritus by the action of water alone. Both causes combine 

 to diminish the amount of lime and to increase the amount of clay, the first 

 being about 14 % in the loess as well as in the glacial marly mud (bond-moraines 

 of the Swedish authors) covering a great part of the surfi^ce of the northern 

 European plain, and only about 2 % in the upper diluvial deposits of Japan, 

 whilst the sesquioxyd of aluminium, about 8 % in the loess &c., rises to tlie double 

 amount in the latter. In the other substances, especially in the amount of silica 

 and iron, there is no essential difference. 



For instance, we have G2i percent of siliceous acid in the loess and 05 in the 

 Japanese soil. The only difiercnce still to be noticed is the presence of a small 

 percentiigo of alkalis (2.3 totally) in the loess — a difference which, as has been 

 already stated, is doubtlessly due to the dissolving action of atmospheric water 

 just as well as the small amount of lime. 



The soil in question is practically of a very great importance. It renders 

 the plain of Tokio fertile even in those parts whicli are not situated in river- 

 valleys and depressions (filled with the alluvial deposits sketched in the foregoing 

 chapter); although nf.t all of the higher j.lains arc cr.ltivated, yet their vegetation 

 is almost everywhere a copious nay luxuriant one. The tree-plantations and the 

 woods are thriving, the groiips of trees round the villages and temj)les are quite 

 as richly developed as those in the lower ground."«, ami i vm the bainl>oo isscarcvly 



