492 E. BLACKWELDER THE GROS VENTRE SLIDE 



cisco, in which unconsolidated material rendered semi-fluid by saturation 

 with water had been caused to flow. The earthquake of 1906 seems to 

 have started them. 



Mr. Whitman Cross's photograph and description^ of the "Slumgullion 

 mud-flow/' in southwestern Colorado, suggest some points of resemblance 

 to the jGrros Ventre slide. He thinks, however, that this flow must have 

 been the result of one or two sudden slumps, but flnds evidence of more 

 recent readjustments in various parts of the mass. 



The Gros Ventre slide differs from most well known landslides in that 

 it had a period of slow and prolonged movement, whereas landslides are 

 generally launched precipitately and end at once. In Howe's classifica- 

 tion* of landslides it should be placed with the mud-flows, in which a 

 mass of earthy matter saturated with water has flowed like a stiff liquid. 



3 Cross and Howe : Landslides in the San Juan Mountains, Colorado. U. S. Geol. 

 Survey, Professional Paper 67, 1909, p. 40. 

 * Ibid., p. 55. 



