INLAND DUNES. 675 



large quantities, for improving the consistence of the tough clay 

 bordering upon or underlying diluvial deposits, and for forming 

 an artificial soil for the growth of certain garden and ornamental 

 vegetables. When the dunes are removed, the ground they cov- 

 ered is restored to the domain of industry ; and the quantity of 

 land recovered in the Netherlands by the removal of the barren 

 sands which encumbered it, amounts to hundi-eds and perhaps 

 thousands of acres. ' 



Inland Dunes. 



Yast deposits of sand, both in the form of dunes and of plains, 

 are found far in the interior of continents, in the Old World and 

 in the New. The deserts of Gobi, of Arabia, and of Africa have 

 been rendered f amihar by the narratives of travellers, but the sandy 

 wildernesses of America, and even of Europe, have not yet been 

 generally recognized as important elements in the geography of 

 the regions where they occur. There are immense wastes of 

 drifting sands in Poland and other interior parts of Europe, in 

 Peru, and in the less known regions of our own Western terri- 

 tory, where their extent is greater than that of all the coast-dunes 

 together which have hitherto been described by European and 

 American geographers.* 



The inland sand-hills of both hemispheres are composed of sub- 

 stantially the same material, and aggregated by the action of the 

 same natural forces as the dunes of the coast. There is there- 

 fore a general resemblance between them, but they appear, never- 

 theless, to be distinguished by certain differences which a more 

 attentive study may perhaps enable geologists to recognize in the 

 sandstone formed by them.f The sand of which they are com- 



* On the Niobrara river alone, the dunes cover a surface of twenty thousand 

 square miles. — Hatden, Report on Geological Survey of Wyoming, 1870, p. 

 108. 



f American observers do not agree in their descriptions of the form and 

 character of the sand-grains which compose the interior dunes of the North 

 American desert. C. C. Parry, geologist to the Mexican Boundary Com- 

 mission, in describing the dunes near the station at a spring thirty-two miles 

 west from the Rio Grande at El Paso, says : " The separate grains of the sand 

 composing the sand-hUls are seen xmder a lens to be angular, and not rounded, 

 as would be the case in regular beach deposits." — TI. 8. Mexican Boundary 

 Survey, Report of, vol. i., Geological Report of C. G. Parry, p. 10. 



In the general description of the country traversed, same volume, p. 47 



