Davis and Wood.] 
400 
[Nov. 20, 
the front of the Highlands to the limestone belt ; therefore, it can- 
not be admitted that the North Branch has yet had time to cut its 
valley back as far as the limestone b}^ the very slow process of head- 
water gnawing. In the second place, if there had been time enough 
for the suggested process, it would be the stream on the soft rock 
that would capture the headwaters of the other one whose outlet 
was on the harder rocks, and not vice versa ; and indeed there is 
some possibility that this capture may yet be made. The divide 
on the limestone belt is at a height of 470 feet between the North 
Branch and the little tributary of the Peapack which follows the 
limestone out to the lowlands, and there joins the North Branch be- 
low the gorge. The North Branch is at an elevation of 360 feet 
on the limestone just below Roxiticus ; and from here to the di- 
vide above mentioned is a distance of a mile. Where the Pea- 
cock joins the Raritan, the river is only 140 feet above the tide- 
level. 
Some observers see evidence of a fracture in the gorge of the 
North Branch rather than an inheritance from an unconformably 
overlying formation j 1 and it cannot be absolutely denied that such 
may be the case. But the fault cannot be of large throw, for the 
transverse limestone valley is not dislocated on the line of the 
gorge ; indeed there has not as yet been presented any complete 
evidence of the existence of fractures in this district of sufficient 
importance to outrank the limestone belts in giving location to ma- 
tured river courses, in cases where either course was open to natural 
selection. If any fault exist in this neighborhood, it is more likely 
along the Archsean-Triassic boundary than in the line of the river. 
In general it appears that the more closety rivers are studied, the 
less attention they seem to pay to fault-lines ; and the most prob_ 
able conclusion in the present case does not appear to be in favor 
of accepting a fracture as a guide. 
27. Distribution of revived and inherited valleys in and near 
the Highlands. Most of the streams of the Highlands are parallel 
to the general structure of the region and follows its softer rocks ; 
and of the several transverse streams, none can give so clear in- 
dication of an inherited course as the North Branch of the Raritan. 
The Delaware needs no such explanation ; it is essentially a revi- 
val of the master-stream that gave outlet to a large area of back 
1 Nason, Geol. Survey N. J., Ann. Kept., 1888, 43. Britton states that the Pequan- 
nock is located on a transverse fault. Ann. Rep., 188C, 122. 
