l6o EDITORIAL 



in this country ; but it should perhaps be pointed out that the Tertiary 

 age of these morainic formations is not to be accepted, except on 

 the basis of the most irrefutable evidence, and evidence of this sort 

 is not cited in the article. The glacial deposits are interbedded with 

 lava, and since the lava has been thought to be of Tertiary age, the 

 moraines are inferred to be of Tertiary age. If the first of these con- 

 clusions is correct, the second is; but, so far as the evidence cited in 

 this paper is concerned, the argument would seem quite as plausible 

 if stated the other way, namely: Since the sediments interbedded 

 with the lavas are glacial, they are Pleistocene; the lavas interbedded 

 with them are therefore Pleistocene. Indeed, the presumption is 

 strongly in favor of this statement, since abundant lavas of Pleistocene 

 age are known, and no glacial formations of Tertiary age in any part 

 of the earth are known, unless these constitute the exception. If 

 they are really of Tertiary age, the fact is most significant, since it 

 will call for a revision of present opinion concerning the climate 

 of some part of the Tertiary period. 



On the other hand, great deformations, great erosion-uncon- 

 formities, and great physiographic features due to erosion have been 

 developed since the close of the Tertiary, and igneous eruptions of 

 consequence are known to have taken place, in America at least, 

 since the Tertiary period. Accumulating evidence makes it clear 

 that the rather common conception that the Pleistocene period was 

 a very short one, must be abandoned. The evidence is now altogether 

 adequate to show that the period was long enough for changes and 

 events far greater than those which have taken place in Iceland since 

 the inter-lava drift of that island was deposited. 



R. D. S. 



