Davis and Wood.] 
372 
[Nov. 20, 
After describing the great distortion and folding of the highland 
rocks, Professor Cook continues : “ It is to be remarked that there 
is a great degree of uniformity in the altitudes of the mountain ranges 
of the Highlands. A large area south of Dover and Rockaway and 
west of Morristown has an average elevation of 800 to 900 feet. 
And the traveller attaining the summit of this plateau, as it were? 
recognizes the general level as characteristic of it. The broad School- 
ey’s mountain range, extending southwest to where the Central 
railroad crosses it, is another example of this uniformity of height, 
having an average elevation from 1000 to 1200 feet. Scott’s moun- 
tain has about the same average height. Another remarkable ta- 
ble-land is in the northeastern part of Sussex and the western part 
of Passaic counties. Its mean height is probably over 1200 feet, 
as there are many summits over 1400 feet, and scarcely any de- 
pressions less than 1000 feet. The surface is by no means level 
or even an approximation to a plane ; but there are no very promi- 
nent peaks or ridges, nor any deep hollows or valleys. This uni- 
form feature of the surface is not accidental, but must have had its 
origin in some way related to the original uplifting and folding of 
the strata, modified greatly by the subsequent erosion due to the 
drainage and glacial action in part.” 1 
6. Development of the Highlands. It may now be asked what 
was the antecedent land-form from which the present Highlands 
have been developed ; and if any trace of this antecedent form 
still remains, the geographer may legitimately extend his inquiry 
to include its examination. 
We know from the general principles of valley-making and land- 
sculpture that any surface exposed to denudation is worn fastest 
along the stream lines, until they approach base-level, and is wast- 
ed slower on the interstream surfaces. Given a plateau, for exam- 
ple, whose base-level is B-L, its profile in successive stages of de- 
velopment might be roughly illustrated in fig. 2. The heavy line 
may be taken as the average present form of the Highlands. Then 
l Id.,G 0, 61. 
