Loess of lozva City — Shimek. 357 
Unio rectus Lam. Common. 
Unio rubiginosus Lea. Not rare. 
Unio securis Lea. Rare. 
Unio spatulatus Lea. Rarther common. 
Unjo tenuissimus Lea. Rare. 
Unio trigonus Lea. Very common. 
Unio tuberculatus Barnes. Very common. 
Unio ventricosus Barnes. Very common. 
Unio undulatus Barnes. Quite common. 
Unio verruccsus Barnes. Rare. 
Margaritana complanata Barnes. Common. 
Margaritana hildrethiana Lea. Locally common. 
Margaritan.\ marginata Say. Rather rare. 
Margarirnana rugosa Barnes. Quite common. 
Anodonta edentula Say. Common. 
Anodonta ferussaciana Lea. Not rare. 
Probably other species of Anodonta occur. 
A summary of the aquatic species here Hsted presents the 
following results : 
Aquatic species found here both living and fossil 5 
Aquatic species living here and occurring in the loess elsewere. 7 
Aquatic species of the occurrence of which in undoubted loess 
no record exists 66 
Total 78 
It will be observed that the proportion of local aquatic 
shells found in the loess, here or elsewhere, is comparatively 
insignificant, and what is true of species applies with even 
greater force to individuals. The fossil shells of aquatic 
species, with the two exceptions already noted, occur very 
sparingly indeed. The writer's own sets of these fossils, 
a part of the fruit of twenty years of careful search, form 
such an insignificant part of his collection that they seem 
scarcely worthy of serious attention. But it will l)e further no- 
ticed that even these aquatic fossils belong to the fauna of the 
small pond or streamlet which may, and often does, remain 
dry during the greater part of summer, and that their pres- 
ence in no wise proves that large bodies of water existed 
where the loess was deposited. Indeed the total absence of 
species which are . truly fluviatile, or which at least prefer 
larger bodies of water, would point to the contrary conclu- 
sion. These fluviatile species are today very abundant in this 
vicinitv, and their shells are, for the most part at least, quite 
