Geological Papers. 107 



loess deposits of the lower Mississippi valley, the loess of 

 China, the Albuquerque loess (Herrick), and many other loess 

 deposits are not within 500 miles of any glacial region. 

 {d) The loess of the Mississippi river and tributaries is on the 

 leeward side of the streams, or is at least highest on that side, 

 which seems to be good evidence of wind accumulation, 

 (e) The loess varying in altitude from 500 to 1000 feet within 

 a few miles at many places in the central valley of the United 

 States seems to be an unsurmountable obstacle to the water- 

 deposition theory. (/') It is difficult to see how sediment of 

 any sort could be deposited in water without being stratified, 

 the loess with few exceptions being unstratified. {g) The fos- 

 sils in the loess of Iowa as well as in that of the Rio Grande 

 region. New Mexico, are, with two exceptions, all land species, 

 and the exceptions belong to the pond type of fossils, thus 

 seeming to indicate that no large body of water ever occupied 

 the region during the formation of the loess. To use the words 

 of Mr. Shimek, above, "had large streams or other large bodies 

 of water existed where the loess is deposited, thus furnishing 

 conditions favorable to a fluviatile fauna, it is reasonable to 

 suppose that some of these shells would be found fossil to-day 

 to relate the story of the conditions under which they were de- 

 posited. Yet no such evidence has ever been found." The 

 fossils of the loess, identified by Shimmek and others, are 

 identical with those now found on the steppes of Asia, where 

 that deposit is now in the process of formation. The evidence 

 from this point of view, that taken by Mr. Shimmek, seems to 

 point to the conclusion that the loess was formed by subaerial 

 action which was principally seolian. The ever-blowing winds 

 blew dust from the mountains, table-lands and plains and from 

 the barren areas at the foot of the glacier. This dust collected 

 in grassy regions and in the valleys and canyons, where it was 

 so protected that it was not moved farther by the winds. There 

 it accumulated, the puzzle of the geological world. 



Again, to return to the view taken by Messrs. Chamberlin 

 and Leverett (and they are still finding evidence to verify 

 their hypothesis), the loess seems to have been deposited, for 

 the most part, by glacial streams at or near the foot of the ice- 

 sheet. To use the substance of Mr. McGee's conclusion on this 

 subject, (a) the loess is commonly fine, homogeneous, free 

 from pebbles or other adventitious matter, and either massive 

 or so obscurely stratified that the bedding plains are usually 



