370 NATURAL HISTORY BULLETIN. 



streams or lakes, have been found in the loess. The recond 

 observation, — on "the presence of land - shells of species that 

 live on the shores of ponds," — is not correct, and the writer 

 has repeatedly called attention* to the fact that the vast ma- 

 jority of loess fossils are those of species which inhabit high, 

 comparatively dry grounds, and this statement has been sub- 

 stantiated by detailed lists. The third conclusion is also in 

 part incorrect. The writer's arguments have applied not only 

 to a "permanently standing body of water," but to any large 

 body of water, and more particularly to large bodies of mov- 

 ing water, f 



Moreover, the loess fauna shows a total absence of the mol- 

 luscs inhabiting large streams, — i. e., the strictly fluviatile 

 forms, — and this fact indicates that there were no such streams 

 where the loess was deposited. 



Professor Wright's comment on the fourth conclusion con- 

 cerning the influence of vegetation as a dust retainer is also 

 likely to lead to a misconception. His reference to this as an 

 "ingenious reversal of a former opinion" would make it appear 

 that this was merely an opinion, — a device for supporting a 

 theory. As a matter of fact it is the result of long-continued 

 field observations in plant - ecology. It is evident that Pro- 

 fessor Wright here entered an unfamiliar field, or he would 



* "A Theory of the Loess," Proc. la. Acad. Sci., vol. iii, pp. 83, 85. 

 "Is the Loess of Aqueous Origin ?" 1. c. , vol. v, pp. 33, 39. "The Dis- 

 tribution of Loess Fossils," 1. c., vol. vi, p. 103; Jour, of Geol. , vol. 

 vii, pp. 127-132. '' The Loess of Iowa City and Vicinity," Bull. Lab. 

 Nat. Hist., St. Univ. of la., vol. v, pp. 2<)6, 212; Am. Geol., vol. xxviii, 

 p. 353. "The Loess of Natchez, Miss.," Am. Geol., vol. xxx, pp. 

 289, etc. " The Loess and the Lansing Man," 1. c. , vol. xxxii, p. 367. 

 This Bulletin, pp. 312-13, 343. 



tViz: "A Theory of the Loess," 1. c. , p. 86. This Bulletin, pp. 

 315-6, 366-7, etc. 



