EVIDENCES(?) OF WATER-DEPOSITION OF LOESS. 379 



"Helices" is very comprehensive, and includes forms which 

 vary very much in habit. Species of the genera Pupa and 

 Succinea exhibit the same variation in habits. Is Professor 

 Broadhead quite sure that he found the same species through- 

 out in both the wreck-heaps and the loess? The writer has 

 collected thousands of shells along the Missouri river from both 

 sources, and among them he frequently found shells that were 

 evidently washed from the near-by highlands, mingled with 

 those of lower grounds. Will Professor Broadhead explain 

 where such shells developed when the highest loess-bearing 

 ridges were covered with water, as he assumes ? But the shells 

 of the "wreck-heaps" are not identical throughout with those 

 in the loess. A comparison of a list of modern shells from 

 Nebraska City and Sioux City, collected in river drift, with 

 the shells of the lcess, may be of interest: 



