334 NATURAL HISTORY BULLETIN. 



higher grounds without floods has also been shown by the 

 writer.* 



The following specific references may be added: Several 

 years ago the writer saw a crow picking at a small fresh Unio 

 on a timbered river-bluff not less than fifty feet above the 

 river, near the state quarries north of Iowa City. The Unio 

 was on the ground and was probably brought up from the 

 river, then at a low stage, by the crow. 



About twenty-two years ago, while engaged in zoological 

 work as a college student, the writer shot a solitary sandpiper 

 one of the toes of which was clasped by a living Sphcerium 

 transvei sum, a small aquatic bivalve. This might easily 

 have been dropped on high ground in one of the longer 

 flights of the bird. 



Three years ago the writer found a medium-sized shell of 

 Campeloma subsolidum on a rocky, almost inaccessible slope 

 below the University observatory at Iowa City, at a point not 

 less than forty feet above the river. The shell, though dead, 

 still retained its epidermis. Campeloma subsolidum lives 

 abundantly in the river, and at low water is often exposed on 

 the sand-bars near this bluff, from which blue-jays or other 

 birds could have easily carried it for food while it still con- 

 tained the soft parts. 



In view of these facts, and of the numerous possibilities 

 suggested by them, it is extremely rash to say that "the ex- 

 istence of a single aquatic fossil species in the loess requires 

 the presence of water," for such shells as those which have 

 been mentioned could be covered by dust, and in time become 

 fossils in a land-deposit. Manifestly, this "strongest evidence 

 of the subaqueous origin of the loess" is very weak and un- 

 satisfactory. 



The advocates of the aqueous theory can find little solace 

 in the fossils of the loess, and without them their case has but 

 little tangible support. 



*Proc. Ia. Acad. Sci., vol. v, p. 37, 1898. 



