No. 386.] THE PENEPLAIN. 131 
the original position of the same peneplain. But, granted that 
there be no recent peneplain at or near the present sea level, it 
would not prove that such plains have not been formed in past 
geologic ages. Late Tertiary time has been that of excep- 
tional energy in mountain-building on the lands, and very prob- 
ably in drowning of parts of the continental ridges in the 
ocean. Both of these correlated causes might well bring about 
an important lowering of the sea level simultaneously about all 
the continents. The result of such movements would be to 
raise some of these plains above their ideal position near the 
sea, to tilt others either toward or from the sea, and, possibly, 
to leave one in about its original attitude with respect to the 
ocean level. 
4. Professor Tarr goes farther and denies that there has yet 
been adduced evidence that there exist peneplains of ancient 
date, z.e., those which have been uplifted and are being dis- 
sected in a new cycle of geographic development, or those that 
have been buried in sediments after depression ; the peneplain 
theory is useless because there is no peneplain to need expla- 
nation. To establish this doctrine he gives us the results of 
his study of the uplands of New Jersey and New England. 
He finds five hundred feet of difference in the tops of the 
New Jersey hills, and about as much in “ the very even-topped 
Kittatinny Mountains.” “There is a very distinct lack of uni- 
formity in the elevation of the upland crests”; it is truly a 
distinct lack, but is it, even on the showing of Professor Tarr’s 
figures, sufficient to remove the topographic facet represented in 
the average level of these higher points from the category of 
an almost-plain? He tabulates the ranges of elevation on the 
survey sheets of Connecticut as follows: 
Cornwall . . . . 1787-1215 feet, a range of 572 feet. 
Winsted aE ee a “ a 44o & 
Granby $ + 0. 1240-720... * eta. n 
Monn o a lowland 
Tolland naen e Oeo EE aAA T Petal 
Woodstock . = . = 761-540 “ i MRS Oe 
He concludes that it is more important to emphasize the 
total range of elevation of the crests in this 91 miles than to 
