413 
[Davis and Wood. 
Although the dislocation may at first sight seem somewhat sur- 
prising, it does not appear to differ from many well known facts. 
The forces of dislocation know nothing about baselevelled regions : 
they act where the resistance of the whole mass subject to them is 
least, and it is indifferent to them whether the plane of action out- 
crops on the surface of the constructionally level lava plains of 
southern Oregon or on the once baselevelled plains of central New 
Jersey. The result in either case is dislocation and tilting of what 
was before level and continuous. 
Other portions of the lowlands produced in the Somerville cycle 
also give evidence of change of level. The Kittatinny valley-low- 
land has suffered elevation since it was reduced to a peneplain, for 
its interstream surfaces now stand at an altitude of four hundred 
or more feet. This is decidedly greater than the height of the cor- 
responding surface of denudation in the Central plain about Bound 
Brook, but it has not yet been possible to determine whether the 
inequality is due to warping or to faulting. The Highland valleys 
are not broad enough to give definite record of the position of the 
Somerville baselevel on the contoured maps, but a brief sight of 
them from a railroad excursion gave encouragement to think that 
deliberate examination on the ground might solve the problem ; the 
streams appear to have sunk young trenches below the general 
valley bottom. 
33. Valleys of the Millstone cycle. The elevation of the coun- 
try from its Somerville attitude has revived the streams and carried 
them into a new cycle of work. The streams in well marked val- 
leys, such as those of the Highlands, where Somerville time was 
not nearly sufficient to accomplish baselevelling, give no indication 
of any change from their Somerville courses ; but, as suggested 
above, they seem in some cases to have trenched new channels 
in the flat-bottomed valleys of earlier (Somerville) date. This is 
much more apparent in the Kittatinny valley, where the Delaware 
flows in a steep-sided valley a hundred or more feet below the gen- 
eral valley-lowland, and its side streams trench the lowland as it 
has given them opportunity. The Lehigh from Easton to Bethle- 
hem in Pennsylvania exhibits this relation with great clearness, 
and many other examples might be named. 
The same thing appears in the Central plain : the traveller on 
the Pennsylvania railroad cannot fail to be impressed by the nar- 
row cut of the Raritan at New Brunswick ; or, if crossing the state 
