BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 23, pp. 487-492, PLS. 28-32 OCTOBER 21, 1912 



THE GEOS VENTRE SLIDE, AN ACTIVE EARTH-FLOW ^ 



BY ELIOT BLACKWELDER 



{Presented hy title before the Society December 28, 1911) 



CONTENTS 



Page 



Introductory 487 



Geologic conditions affecting the slide 487 



History of the slide 489 



Present characteristics of the slide 490 



Importance of earth-flows 491 



Classification 491 



Introductory 



Most settlers and others who have recently visited the mountains south 

 of Yellowstone Park know "the Gros Ventre slide." Its wide reputation 

 is due largely to .the fact that for several years the landslide made com- 

 munication between the upper and lower parts of the valley of the Gros 

 Ventre River difficult and uncertain. Although the name which heads 

 this paper is the one generally used in the vicinity, it is not quite satis- 

 factory to the geologist, because it suggests the sudden plunge and im- 

 mediate quiescence which attend landslides and avalanches in general. 

 As the facts presented in these pages indicate, the term "earth-flow," or 

 even "earth-glacier," would be more appropriate in this case. 



The position of the slide may be found by consulting the southwest 

 part of the Mount Leidy, Wyoming, topographic sheet, published by the 

 United States Geological Survey. It occupies the valley of Lake Creek, 

 one of the many small southern tributaries of the Gros Ventre River. 



Geologic Conditions affecting the Slide 



In order to understand the phenomenon itself, it is necessary to know 

 the geologic structure and topography of the locality. The Gros Ventre 



^ Manuscript received by the Secretary of the Society January 29, 1912. 

 For the historical data in this paper I am indebted to friends in .Tacltson Hole and 

 vicinity, particularly to Mr. Robert E. Miller, Mr. S. N. I.eek, and Mr. M. J. Itobinson. 

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



(487) 

 XXXV — Bull. Gbol. Soc. Am., Vol. 23, 1911 



