360 E. HUNTINGTON GLACIAL PERIOD IN NON-GLACIATED REGIONS 



was quite surely in the amount of vegetation. Formerly, during glacial 

 times, there was apparently more ; now there is less. It seems safe to 

 infer that this process 'of the growth and the dying off of vegetation has 

 gone on again and again as glacial epochs have given place to interglacial. 

 Similar effects are known to have taken place in other regions. Animals 

 as well as 'plants have been influenced, and so, too, has man, as I have 

 shown in "The Pulse of Asia;" but the most fundamental organic 

 change has been the response of vegetation to varying types of climate. 

 It has probably taken place in almost all parts of the continents. In view 

 of this, it seems as if we were warranted in speaking of "vegetal" epochs 

 with the same freedom with which we speak of "glacial" and "fluvial" 

 epochs. The term is not, however, sufficiently general. Like glacial and 

 all the others, it is somewhat local in its significance, and it applies to 

 only one of the many phases characteristic of epochs of climatic change. 

 Its use, like that of "glacial," or any other of the terms to which reference 

 has been made, is misleading, because it unavoidably carries with it the 

 implication that it expresses the most important feature of the epochs 

 which it characterizes. Each- of the terms is useful, but something is 

 needed which shall embrace them all. 



Eesume of Characteristics of the Pleistocene Period of climatic 



Changes 



The characteristics of the Pleistocene period of climatic changes have 

 been grouped above into four categories : 



First in logical order, though not the most noticeable, are those per- 

 taining to the nature or type of the changes. They are described by such 

 words as moist and dry, cold and warm, pluvial and arid. 



The next group of characteristics consists of those pertaining to the 

 active agents which are directly affected by climatic oscillations, and 

 which in turn work upon other things and produce tangible results, 

 although the agents themselves pass away. They are described by the 

 terms glacial, meaning that glaciers are important, and interglacial, mean- 

 ing that glaciers are unimportant, and by the terms fluvial and inter- 

 fluvial, and lacustral and interlacustral, having similar significance as to 

 rivers and lakes. It might be well to have another pair of terms indi- 

 cating the importance or lack of importance of underground water, but 

 this perhaps may be included in fluvial,' which may be taken to apply to 

 all flowing water, whether above ground or below. 



A third group of characteristics consists of those pertaining to the vis- 

 ible products of the work of the agents of the last group. For those we 

 have no good adjectives. They may be described as concerned Avith mo- 

 raines or intermorainic deposits, with the formation and the stripping of 



