142°" THE AMERICAN NATURALIST. (Vor. XXXIII1. 
emphasize the fact that in any given sheet the total range is 
relatively very small and decreases with the decreasing absolute 
heights of the hills in going from west to east. Is this strik- 
ing accord of elevations to be ignored in an explanation of 
Connecticut scenery? Professor Davis has regarded it as indic- 
ative of a peneplain of the last geographic cycle, now tilted 
towards the east and somewhat dissected, especially on the 
softer rocks, in the present immature stage of a new cycle. It 
is a theory at once clear, definite, and involving no processes 
other than those actually illustrated on the earth at the present 
time. It explains the existing uplands and valleys of the 
regions under discussion, and, above all, the presence of this 
otherwise inexplicable topographic facet which is once more 
established by the foregoing table of Professor Tarr.} 
A second point that he makes against the New England 
peneplain shows a disregard of patent facts which it is most 
difficult to understand in the most superficial survey of New 
England geography. He writes: “In Maine, New Hamp- 
shire, Vermont, western Massachusetts, and the Adirondack 
region, with similar structure to that of the region above men- 
tioned, and so near them that they must have been subjected 
to the same general degradation, the lack of uniformity of up- 
land crests is very much more marked.” The elevation of the 
latter “is 2000 to 4000 feet above the sea.” Now, so far as 
the present writer is aware, neither Professor Davis nor any 
one else has contended that these summits represent any part 
of the peneplain ; they are, on the contrary, stated to be local 
and regional monadnocks interrupting the general surface of 
the peneplain for very good reasons. Among the latter is one 
which has met with contradiction in an expression of the pas- 
sage just quoted, namely, that there is similarity of “structure ”’ 
1 I should not hesitate to speak of an extensive mountain range as a ‘“‘ pene- 
plain” if it no longer showed a range of elevations greater than 572 feet in a 
stretch of gt miles. It is, however, true that the ranges of elevation cited by 
Professor Tarr are determined from the position of streams which have strongly 
incised their beds because of the Tertiary uplift. On the other hand, some of the 
_ higher points may represent extremely low monadnocks overlooking the pene- 
plain of Professor Davis’s definition (range of elevations through 200 or 300 feet) 
_ from altitudes of 100 or 200 feet. 
