BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 19, pp. 53-62, PLS. 3-4 MARCH 31, 1908 



WIND EEOSION IK THE PLATEAU COUNTEY^ 



BY WHITMAN CROSS 



(Read before the Society December SI, 1908) 



CONTENTS 



Page 



Introduction 5-} 



Eolian soil in Colorado 53 



The Plateau country east of Grand River canyon, Utah 50 



Deflation in Dry valley 57 



Application to Plateau province (i 1 



Introduction 



The agency of the wind in the degradation of land areas is generally 

 recognized, in the abstract, as comparable with that of water, excepting 

 as to the magnitude of the work done. It is evident that air currents 

 transport dust and sand particles, and the abrasive action of a sand 

 blast is in kind similar to the erosive effect of a debris-laden flood, but 

 due recognition of the role played by the wind in the erosion of special 

 areas is perhaps not so commonly accorded. Eecent observations con- 

 vince me that the Great Plateau country of the western United States is 

 one of the provinces in which the effective degrading or denuding agency 

 of the wind has not been fully appreciated. The facts on which this belief 

 rests will be presented in the order in which they were observed. 



The first thing to be considered will be certain apparently eolian soils 

 occurring about the mountains in Colorado ; then follows evidence that 

 the wind-blown material came from the Plateau coimtry. A district in 

 Utah where wind work has clearly been done will be described and facts 

 given tending to show the quantitative measure of the work accomplished. 



Eolian Soil in Colorado 



Adjacent to the San Juan mountains of Colorado, and particularly in 

 the larger river systems, there are notable gravel plains at various eleva- 

 tions between 50 and 400 feet above the adjacent streams of today. The 

 higher and older of these plains cover many square miles in the drainage 



1 Published by permission of the Director of the U. S. Geological Survey. Manuscript 

 received by the Secretary of the Society February 3, 1908. 



VI— Bull. Geol. Soc. Am.j Vol. 19, 1007 (53) 



