E. E. Hoioorth—TJie Loess. 349 



Professor Augliey speaks of this wind-structure in some of the 

 Loess hills on the Logan, Elkhorn, Loup, and Kepublican rivers. He 

 says, " This structure is often found there as distinct as among the 

 shifting sands of our sea-coast. In every case, however, where I 

 examined this structure in the Loess, I found it to be superficial. 

 Out of nineteen such hills none of them possessed this structure over 

 ten feet deep, and few of them over five feet, and many of them 

 only from two to three feet deep. In the deep canons, where the 

 Loess is exposed vertically from one hundred feet, I have never 

 found this wind-structure over ten feet deep. It occurs, therefore, 

 only in the Loess that has been recently modified by winds, and 

 long after it was first deposited " (Sketches of the Physical Geo- 

 graphy, etc., of Nebraska, p. 274). It would be difficult to find a more 

 striking proof that the Loess was not originallj'' distributed by the 

 wind than the fact that it so readily assumes a wind-structure, and 

 yet that this peculiarity is only traceable in the superficial layers 

 where the current winds have acted upon it. Again, wind driving 

 dust and sand in a definite direction, as, for example, from the 

 Mongolian steppes towards China, would, in crossing such a broken 

 district as the long tract of mountains bordering the valley of the 

 Yellow River on the north, leave unmistakable traces of its passage. 

 It would strip the high ground completely and choke up the valleys, 

 especially those parts of the valleys under the lea of the mountains ; 

 but nothing of this sort, if we are to follow the careful observations 

 of Pere David and others, occurs ; but the Loess is generally deposited 

 in a mantle, as one American writer says like a blanket, washed evenly 

 over the surface, and not piled up in drifts in those places where the 

 force of the wind could not move it. Again, such a wind would 

 assuredly sift the materials, dropping the heavier ones first, and 

 carrying the lighter ones further away; but this is not what we find, 

 the texture is the same throughout, and throughout, heavy grains 

 of quartz and particles of mica occur confusedly among the finer 

 siliceous dust, as Baron Eichthofen himself says. Again, the process 

 described by the Baron would surely rub down the particles of dust 

 by trituration against one another, and make them rounded and 

 weathered, whereas, as he has remarked in China, and other ob- 

 servers in America, a remarkable feature of the Loess is the sharp- 

 edged and angular particles out of which it is formed. 



Baron Eichthofen explains the Loess as composed partially of 

 dust brought in by winds and partially as the result of the decay 

 of grasses and other vegetable matter. The proof of the existence 

 of these grasses he finds in the calcareous tubes we have mentioned. 

 But apart from the reasons we have urged against the capillary tubes 

 being treated as casts of roots, upon which a good deal of the reason- 

 ing in regard to the vegetable debris in the Loess depends, we must 

 remember that the various analyses that have been made, especially 

 of the American Loess, show that there is hardly a trace of carbona- 

 ceous matter in it — assuredly a very strong proof that the amount of 

 material due to decayed vegetation in the Loess is hardly appreciable. 

 This is true also of the black earth of Kussia, and is in very marked 



