1889 .] 
377 
[Davis and Wood 
it is not likely that distortion is accountable for the gentle undu- 
lations of the ancient plain. 
11. Conclusions as to the origin of the Highland peneplain. We 
may therefore conclude that, whatever was the earlier history and 
form of the Highland region, it once stood with its present upland 
surface but little above sea-level for a period long enough to be 
worn down to a lowland of moderate relief, and that it was subse- 
quently lifted bodily to its present elevation. 
This may on first reading seem out of place in a geographic es- 
say ; but just so much of the past as is needed to explain surface 
forms still in existence is fairly within the province of systematic 
geography. Certain it is that no sufficient comprehension of the 
geography of the New Jersey Highlands can be gained without thus 
turning to the past for an explanation of their broad uplands. Ge- 
ology need not grudge what seems at first like a trespass on its 
province ; it has enough to do with the still earlier history of the 
Highlands, the discussion of their rocks and of their ancient dislo- 
cations that have left no mark on the present surface ; indeed the 
trespass, if it be such, may be to the advantage of geology in suggest- 
ing points of view before unnoticed. 
12. The Schooley baselevel. The general altitude of the surface 
of the sea with respect to the land during the development of the 
present upland surface of the Highlands constitutes an important 
plane of reference, which will be named the “Schooley baselevel ;” 
and as we have concluded that the greater part of the denuded area 
was reduced to a surface of gentle relief by subaerial forces, the 
surface itself as then worn down, although by no means perfectly 
flat, will be called the “Schooley baselevel peneplain/' or more 
locally “ the Highland peneplain.” We shall also speak of the 
“ Schooley cycle,” meaning thereby the time spent in the develop- 
ment of the old plain. 
Geographic inquiry hardly leads us further in the past than to 
the time when the Highlands were lowlands. There is no longer 
any remnant of earlier surfaces in the topography of New Jersey — 
though there may possibly be inheritances from them in the position 
of certain water courses, as Mr. McGee has suggested to us. If 
the reader should, however, desire to reconstruct the still earlier 
antecedent form of the region, from which the Highland peneplain 
was developed, we believe good reasons could be given for argu- 
ing that it was probably a faulted mountainous region of parallel 
