The Peneplain. — Tarr. 369 
valleys standing near the base level and hills of softer strata 
standing at levels still lower than those in which the rock is 
harder. Areas originally distinctly higher or harder than 
usual, or more unfavorably situated, may be less lowered' and 
more irregular than the surrounding region, though still en- 
gaged in an approach to this lower level. A well matured 
surface would then present three intergrading stages in differ- 
ent places and under different conditions, (i) Local base 
levels in the valleys; (2) general well matured topography 
with many hills reaching to approximately the same general 
level, but with some distinct and many indistinct "monad- 
nocks"; (3) exceptional and localized early maturity, found 
particularly in the interior. The further the topographic de- 
velopment had gone toward old age, the greater would be the 
extent of the first two areas. Can any evidence be adduced to 
show that New England has ever advanced further in de- 
velopment than this stage? 
Granting such a reduction, with man}- hills of hard rock 
standing at a moderately regular level if an elevation succeeds, 
while the valleys will be deepened and the hills lowered, the 
rate of lowering of the hills will be so nearl)^ uniform, since 
the climate and rock are so nearly alike, that the measure of 
uniformity of upland level will in part be maintained\ 
Conclusion — The questions raised in this paper are not 
against the great importance of subaerial denudation, which 
few American geologists are inclined to underestimate. The 
stamp of the genius of Powell, Gilbert, Davis and others is too 
plainly marked upon the minds of American geologists for any 
underestimation of the importance of this. The question I 
raise is whether far too much importance has not been as- 
signed to this great work. The facts and assumptions upon 
which the peneplain theory is based are also called in ques- 
tion, and an attempt is made to show that all the phenomena 
believed to indicate the existence of peneplains in New Eng- 
land and New Jersey can best be explained without assuming 
the reduction of a high mountainous country to the condition 
of old age, a condition now nowhere found on the earth. 
The alternate hypothesis of beveling down to mature form 
is advanced. This hypothesis requires no long periods of rel- 
ative quiet, and no assumptions to explain the irregularities of 
