TJie Pc7icplain. — Tarr, 355 
torrents, having their source from 2,000 to 5,000 feet above 
the main river. The Penobscot was not even clouded with - 
sediment. The mountain torrents and the smaller branches ] 
from the primeval forests were doing little more work of 
transportation than that of carrying their slight load of dis- 
solved mineral. This period represents one of the three or 
four annual freshets when the greatest amount of work of de- 
struction is done in the drainage area. But, even at such a 
time, the work done was marvelously slight in amount. Dur- 
ing the remainder of the year, still less is done. Yet this is 
a mountainous region where demidation is certainly nmch 
more active than it would be in a more reduced area approach- 
ing the peneplain stage. At this race how long will it take to 
reduce Mt. Katahdin, from its elevation of about a mile, and 
its neighbors, only slightly lower, to the condition of a pene- 
plain? / 
During all the time necessary to reduce a hilly country to 
the condition of a "nearly featureless plain," tinup to be 
counted in inmiense ages, the land must remain nearly 4t one 
level: for if it is elevated, the task is increased, and the time 
needed for reduction correspondingly lengthened; if much 
depressed a part of the lowered region is submerged, and the 
work checked, or perhaps even lengthened by the deposit of a 
load of sediment upon it, which must be removed before fur- 
ther lowering can be accomplished. 
The belief in the reduction of a country to the condition 
of a peneplain rests upon an assumption very difificult to real- 
ize, but which could be granted if the peneplain were proved to 
represent a real condition, and this to be the sole explanation. 
This assumption of innnense periods of time, with relative 
land quiet during certain periods of the earth's history, con-\ ' 
flicts so markedly with what we know of the present and past, 
both immediate and remote, that its acceptance means no less 
than the belief that at some periods of the past the conditions 
have been different from those of the present, and from those\ 
of that portion of the past whose history has been worked out ' 
by purely stratigraphic methodst 
Add to this the fact that the extensive peneplains so far dis- 
covered are all of, the past, and that no [)art 01 the earth re- 
veals even an approximation to this supposed condition, and 
