Davis and Wood.] 
398 
[Nov. 20, 
The branches of such streams may sometimes be independent of 
any streams in the previous cycle and owe their existence simply 
to the backward gnawing of lateral gulleys and ravines ; such would 
be called “subsequent” branches of revived streams. 1 
The control exerted on the form of the Highland valleys by the 
(apparent) synclinals of limestone that lie between (apparent) an- 
ticlinals of gneisses, etc., is finely illustrated at several points, 
perhaps nowhere better than in German valley, where the South 
Branch of the Raritan has its source. This valley is deep and wide 
as far as it is cut on limestone, but at its southern end the bottom 
of the limestone trough appears to have risen above the Somerville 
baselevel, and consequently the stream has here sunk a narrow 
gorge about live miles long in the gneiss. The exit from the con- 
stricted gorge to the broadly roll- 
ing Triassic plain at High Ridge 
is highly suggestive, when it is re- 
membered that the difference of 
form between the gorge and the 
plain is not due to difference of 
age, but to difference in hardness 
and consequent difference in rate 
of wasting of their rocks. 
The Musconetcong in its lower 
course, about six miles from its 
junction witli the Delaware, cuts 
into a longitudinal saddle of gneiss 
that separates the limestone troughs 
of its upper and lower course : this is also probably a disclosure 
made by the river in the Somerville cycle. The same may be said 
of the transverse escape of the Pequest from one longitudinal lime- 
stone valley to another, seven miles east of Belvidere ; the loca- 
tion of the cross-cut was probably determined by a sag in the in- 
tervening anticlinal of gneiss which allowed the limestone here to 
wrap over the gneiss from one synclinal valley to the other. All 
these examples where the streams have cut down from limestone 
to a much harder rock, that would not otherwise be chosen for 
stream courses, may be regarded as “ locally superimposed.” The 
relative length of the Musconetcong and the Pohatcong, fig. 7, is 
i Nat. Geogr. Mag., I, 1889, 207. 
