ANCIENT GLACIERS IN EASTERN HEMISPHERE. 187 



The distribution of loess in Europe was doubtless con- 

 nected with the peculiar glacial conditions of the con- 

 tinent. Its typical development is in the valley of the 

 Rhine, where it is described by Professor James Geikie 

 " as a yellow or pale greyish-brown, fine-grained, and 

 more or less homogeneous, consistent, non-plastic loam, 

 consisting of an intimate admixture of clay and carbonate 

 of lime. It is frequently minutely perforated by long, ver- 

 tical, root-like tubes which are lined with carbonate of 

 lime — a structure which imparts to the loess a strong 

 tendency to cleave or divide in vertical planes. Thus it 

 usually presents upright bluffs or cliffs upon the margins 

 of streams and rivers which intersect it. Very often it 

 contains concretions or nodules of irregular form. . . . 

 Land-shells and the remains of land animals are the most 

 common fossils of the loess, but occasionally fresh-water 

 shells and the bones of fresh-water fish occur." 



" From the margins of the modern alluvial flats which 

 form the bottoms of the valleys it rises to a height of 200 

 or 300 feet above the streams — sweeping up the slopes of 

 the valleys, and imparting a rich productiveness to many 

 districts which would otherwise be comparatively unfruit- 

 ful. From the Rhienthal itself it extends into all the 

 tributary valleys — those of the Neckar, the Main, the 

 Lahn, the Moselle, and the Meuse, being more or less 

 abundantly charged with it. It spreads, in short, like a 

 great winding-sheet over the country — lying thickly in 

 the valleys and dying off upon the higher slopes and 

 plateaux. Wide and deep accumulations appear likewise 

 in the Rhone Valley, as also in several other river-valleys 

 of France, as in those of the Seine, the Saone, and the Ga- 

 ronne, and the same is the case with many of the valleys 

 of middle Germany, such as those of the Fulda, the "Werra, 

 the Weser, and the upper reaches of the great basin of 

 the Elbe. It must not be supposed that the loess is restricted 

 to valleys and depressions in the surface of the ground. 



