Rwers of Northern New Jersey.» 85 
makes brief mention of what I have called subsequent streams. 
The first appreciation that I gained of river adjustments came 
from the writings of Léwl; but I have since found that the 
general principles governing their opportunity were stated by 
Gilbert in his monograph on the Henry Mountains of Utah (pp. 
141, 149), and a Heim in his Mechanismus der Geir bildune 
(i, 272, ete., ii, 79, 320). 
Where e fate rivers of northern New Jersey stand in this 
general scheme of river classification? We must again postpone 
the answer to the question, while reviewing the history of the 
general geographical development of the region.* 
The topography of northern New Jersey may be briefly de- 
scribed as made up of valleys and lowlands that have been etched 
in the now elevated surface of what may be called the Schooley 
peneplain on the Cretaceous baselevel. The topographical atlas 
of New Jersey should be constantly referred to, in order to follow 
such a statement as this ; but in order that the reader may with- 
out undue difficulty apprehend the meaning of my descriptions 
and recognize the various localities yet to be named without the 
trouble of searching for them on the maps of the atlas, I have 
attempted to draw a generalized bird’s eye view of northern New 
Jersey, as it would be seen by an observer about seventy miles 
vertically above the center of southern New Jersey. The merid- 
ians are vertical and east and west lines are horizontal, but oblique 
azimuths are foreshortened. The result is hardly more than a 
geographical caricature, and I publish it im part to experiment 
upon the usefulness of so imperfect an effort. An active imagin- 
ation may perceive the long even crest line of Kittatinny Mountain 
on the northwest, rising beyond the rolling floor of the Kittatinny 
Valley, as the great Alleghany limestone lowland is here called ; 
then come the Highland plateaus, of accordant altitude one with 
another, but without the mesa-like margin that my pen has not 
known how to avoid indicating. The Central plain lies in the fore- 
ground, diversified by the various trap ridges that rise above its 
surface ; First and Second mountains of the double Watchung 
*The more detailed statement of this history may be found in an 
essay prepared by the author with the collaboration of Mr. J. W. Wood, 
Jr., of the class of 1888 in Harvard College, the study being undertaken 
as a joint thesis by instructor and student in a second course in Physi- 
cal Geography. The essay is published in the Proceedings of the Boston 
Society of Natural History, 1889. 
