238 



PREHISTORIC EUROPE. 



in the loss is quite in keeping with the theory which attributes 

 that deposit to the action of muddy inundation-waters, a view 

 which is strongly supported by Professor F. Sandberger and 

 others who have made a special study of the question. The 

 shells, as Sandberger has shown, bespeak colder conditions of 

 climate, and belong to species which for the most part occupy 

 damp and shady places. They are just such forms, indeed, as 

 may have lived in woods and meadows near the borders of 

 streams, rivers, and lakes, and which therefore would be liable 

 to be swept away during floods and inundations. Moreover, 

 they probably represent only a fraction of the terrestrial 

 molluscous fauna of the period. Thus in the lists given by F. 

 Sandberger, A. Braun, Gysser, Leydig, and Heynemann, of shells 

 obtained from the loss of the valleys of the Main, the Neckar, 

 and the Upper Ehine, there is only one freshwater-shell (Lim- 

 neus truncatulus) to some eighteen species of land-shells. Dr. 

 Sandberger tells us that in the mud brought down by the flood- 

 waters of the Main on February 19, 1876, he observed 52 species 

 of shells, namely — land-shells, 38 species ; freshwater-shells, 14 

 species. The contrast was still more striking when the numbers 

 of individuals were taken into account. Thus, while freshwater- 

 univalves and bivalves numbered only 69 individuals, the land- 

 shells were no fewer than 10,747. The species which were 

 most abundantly represented were as follow : — 



Helix pulchella and H. costata 

 Pupa muscorum 



4228 

 3550 



examples. 



55 



P. pygmcea . 

 CceciUanella acicula . 



654 

 596 



55 



5J 



Cionella lubrica 



574 



55 



Chondrula tridens 



209 



5) 



The smaller species are thus by far the most abundant in 

 the inundation-muds of the present day, just as they are in the 

 old valley-loss. The wide diffusion of these forms in the loss 

 offers no difficulty. Their extreme lightness would insure their 

 dispersion to great distances. Even larger species might under 

 certain conditions be transported a long way. Captain Feilden, 



