PLEISTOCENE LOAMY DEPOSITS. 145 



more apart, may be traced running horizontally across the face 

 of a deep cutting ; and now and again intercalated layers and 

 laminae of sand make their appearance. Here and there too we 

 may encounter stones either isolated or in little patches and 

 groups, and in places where the accumulation abuts against a 

 cliff or rock-slope, it not infrequently contains intercalated lines 

 and layers of fragments which have evidently been detached 

 from the adjacent rocks and embedded during its formation. 

 Again the loss of some regions loses to a large extent its car- 

 bonate of lime, becomes more argillaceous and passes into a 

 plastic clay, in which condition it would cease to be called loss 

 by sticklers for precise terminology. Or it may graduate into a 

 loam, distinguished from loss merely by the paucity or absence 

 of carbonate of lime. As the loss is a deposit of mechanical and 

 not of chemical origin, we are prepared to meet with such changes 

 in the character of the accumulation. The definition of the 

 typical loss given above applies more particularly to that of 

 Central Europe — to the great loss-deposits of the valleys of the 

 Ehine, the Ehone, and the Danube. In northern France and in 

 the south of England accumulations which occupy the same 

 geological horizon often differ very considerably from the loss of 

 the Ehenish districts, and the same is the case with vast sheets 

 of loam that overspread the south of Eussia. The one character 

 which all these deposits have in common is their extremely fine 

 texture. In other respects they frequently offer considerable 

 contrasts. As a rule they form admirable soils, and it is to 

 them that many of the most productive regions of Europe owe 

 their fertility. 



Loss, as I have said, is typically developed in the regions 

 watered by the Ehine and its tributaries. Erom the margins of 

 the modern alluvial flats which form the bottoms of the valleys it 

 rises to a height of 200 and 300 feet above the streams — sweep- 

 ing up the slopes of the valleys, and imparting a rich productive- 

 ness to many districts which would otherwise be comparatively 

 unfruitful. From the Eheinthal itself it extends into all the 

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



