$10 CHARLES Te KEVAES: 
from the standpoint of the finished products. The idea that the 
latter are the visible expressions of many and constantly chang- 
ing agencies has received only indirect or secondary practical 
consideration. Asa result the production of many, if not most, 
geological features are loosely, or in a very vague way, ascribed 
to causes that are very complex. That is, instead of being single 
and simple the ascribed agencies are in reality a combination of 
several very distinct causes. For example, rock weathering is 
usually spoken of as if it were a single process in operation; 
whereas it involves the action of at least three distinct forces, 
one of which is strictly physical and the other two chemical, 
that are called into play separately or in conjunction. 
So far as concerns the standpoint of treatment, the newer text- 
books on geological science are not much of an improvement 
over the older ones. The antiquated plans of making the prod- 
ucts all important and of not distinguishing between proc- 
esses still thoroughly permeate them. In some cases a little 
more space than formerly is devoted to ‘‘dynamical” geology, 
and a little less stress is placed upon the so-called historical 
section. Otherwise, there is relatively small difference between 
the geological manuals of today, and those of a quarter or a half 
century ago. 
At this time it is not quite clear just what are the real reasons 
for this lagging of the manuals so far behind the science itself. 
Not the least important factor probably is that, as a rule, the 
makers of popular text-books are not in a broad way creative or 
productive investigators. The advance movement in geology 
began nearly a score of years ago, and today it is quite generally 
appreciated by all active workers, who face the subject in nature. 
While it was only natural that geology should finally come to 
be placed upon a strictly genetic, or philosophic, basis, it was due 
primarily to the modern geographic school that the first strong 
impulses in this direction were given. The geographers, however, 
have not developed their side of the subject in as purely a 
genetic manner as they would have us believe, or as their oppor- 
tunities permit. They certainly began in the right way, but in 
