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On the Physical Geology of the United States, §c. 299 
It has already been mentioned that these folded and disturbed 
strata extend from Canada on the N. through the Atlantic moun- 
tain region to Alabama on the S., a distance of at least one thou- 
sand miles. 'The cause of the disturbance has acted repeatedly 
along the same axis, producing the same effects, raising the solid 
massive strata of the globe into great undulations, crumpling, 
crushing, and pitching them over in some instances in mountain 
masses of folded strata, so as to give them all an eastwardly dip 
in the easternmost ranges. Where the strata are not folded, they 
are often broken by enormous longitudinal, transverse, and lateral 
faults.* These facts, together with contortions, crushed strata, 
_the glazed and shivered slates, and the polished surfaces of fis- 
sures, lead to the conclusion that lateral motion has been pro- 
duced by some cause. It may be conceded that a cause acting 
over so great an area may have been general, rather than local. 
The phenomena of the earth being in the state of a cooling 
body, that cooling bodies diminish in volume, that bodies revolv- 
ing on axes if diminished in volume and retaining the same 
quantity of matter increase in angular velocity, that the conse- 
quent increased centrifugal force would increase the oblateness of 
the spheriodal form of the earth, and the mobility of water would 
induce a flow of water from the polar to the equatorial regions 
to restore the form of equilibrium, have been considered in the 
preceding pages. 'The same cause of increased velocity of rota- 
tion would tend to produce similar results in the solid strata of 
the globe, if they be capable of yielding to such a force. That 
they can yield to such force is probable, from the fact, that the 
general form of the solid part of the globe, is the form of equi- 
librium of a body like the earth, revolving with its present velocity. 
If the earth has at any time become more oblate in consequence 
of increased angular velocity, inertia would tend to make the 
solid matter of the exterior of the globe press to the westward, 
with a force dependent on its mass and its increased distance from 
the axis of rotation; and if there were lines at which motion 
could take place, slight motion might thus be expected to have 
been produced, and effects on the rocky strata, such as those 
mentioned, would be the necessary results. 
* Vide Geology of Ist Dist. New York, by W. W. Mather, and Rogers’ Geo- 
logical Report of New Jersey, and various geological papers. 
