June, 1920] The Great Mageik Landslide 333 



course of a few years, but as yet they show few signs of decay. 

 These circumstances combine to make it certain that the 

 material was thrown into position very recently. .^ 



On the other side, it is certain that the terrane goes back 

 to the time of the eruption by reason of the fact that its surface 

 is in many places covered with the layers of ash from Katmai. 

 Because of local irregularities in deposition, I have not been 

 able to satisfy myself whether all layers of ash are present or 

 only the upper strata. But it is significant that close beside 

 these spots covered with stratified ash are others which show 

 no sign of ash or in which it is mixed with the debris in such 

 fashion as to indicate that while the mass in the main must 

 have reached its position before the end of the eruption, yet 

 there were minor movements after the ashfall. This combina- 

 tion of circumstances appears to fix pretty definitely the 

 formation of the terrane as co-incident with the eruption. 



The presence of the original vegetation on its surface and 

 other features suggests the similarity of the terrane to a land- 

 slide. Fragments of the original ground surface were similarly 

 transported in the great landslide at Frank, Alberta, as described 

 by McConnell and Brock,* who report, "One large bowlder 

 still retains on its upper surface a coating of moss and a fragment 

 of rotten log lying quite undisturbed." But here again there 

 are important differences which at once distinguish this from 

 the ordinary landslip. Its surface has neither the hummocky 

 billows nor the crescentic ridges so characteristic of landslides 

 in general. Instead it possesses a peculiar type of surface 

 different from anything I have ever seen in regions of ordinary 

 physiography. 



Everywhere the surface of the terrane shows a rnarked 

 tendency to be studded with the most curious conical piles of 

 detritus. Some of these are astonishingly perfect in form. In 

 others the conical form is less perfect. Nevertheless, it is so 

 unusual and so strongly impressed on the topography as to 

 excite the wonder of everyone who beholds it. The pictures 

 on pages 349 and 352 give a good idea of the general char- 

 acter of these cones. 



*McConnell, R. G., and Brock, R. W. Report on the Great Landslide at 

 Frank, Alberta, 1903. Ann. Rept. Dept. Interior, Canada, 1903. p. 10. 



