332 NATURAL HISTORY BULLETIN. 



In this connection the writer desires to refer at some length 

 to certain statements made by Professor Winchell* concern- 

 ing the Unio which was found in the Lansing deposit. In 

 order that there may be no misunderstanding concerning 

 these statements the}' are here reproduced in full: 



"In case the Unio were a true fossil, it would be, of itself, 

 sufficient proof of the subaqueous deposition of the materials 

 in which it lay. Land shells may form fossils in aqueous 

 deposits, but never water shells in land deposits. It is, a 

 priori, however, the strongest evidence of sub-aqueous origin 

 of the loess in which it was found, ... and the agreement 

 which it has with obvious other features of the deposit serves 

 to accumulate such a weight of testimony in the same direc- 

 tion that it requires the greatest hardihood to attempt to ex- 

 plain it on the hypothesis of land origin of the deposit." 



The same author had previously! made the following state- 

 ment: 



"Many land forms may exist in an aquatic formation but 

 the existence of a single aquatic fossil species in the loess re- 

 quires the presence of water. Many have been identified by 

 good authorities." 



In face of the foregoing statements it may be an exhibition 

 of greatest hardihood to venture to still maintain the ground 

 that the loess is of land origin, and that as evidence of the 

 sub-aqueous origin of the loess the Lansing Unio is worthless, 

 but regard for scientific truth makes the exhibition impera- 

 tive. 



Granting for the sake of argument that the Lansing de- 

 posit is true loess, — though the difference of opinion among 

 those who have examined it makes this extremely doubtful, % 

 — if it can be shown that aquatic shells of the fluviatile types, 

 or at least, types of aquatic shells other than such as inhabit 



*Atn. Geol., vol. xxxi, p. 282. 



tBull. Geol. Soc. of Am. , vol. 14, p. 145, April, 1903. 



+ See discussion of the Lansing deposit in the following paper. 



