and the Origin of Mountains. 425 
tion,) mountains of different ages on the same border, or part of a 
border, have approximately the same trend, and thos ose of thesame 
age on n the opposite border—Pacific and Atlantic—have i in general 
a different and nearly transverse trend. Hence, “ one dial plate 
for the mountains of the world, such as Elie de annie deduced 
mainly from European geology, will not mark time for America,” 
(This Journ., II, iii, 398 18473 xxii, 846, 1856. 
e features ‘of the North American continent were to a 
f 
this great chain, and so on in many lines over the continental sur- 
face; and thus its adult characteristics were as plainly manifested 
in its beginnings as are those of a vertebrate in a half-developed 
embryo 
8. Me tamorphism of regions of strata has taken place only 
during periods of epee 1 or when plication and faults were 
In progress ; all metamorphic regions being regions of disturbed 
and generally of piiited ocks. 
The heat ee for alteration came up from the earth’s liquid 
interior. (This of - view dscpiied modification, while the 
other part, I be re remain 
e volcanoes of the continental areas are mostly confined 
9. 
to the sea-borders, or the oceanic slope of the border mountain 
valve 
10. She rthquakes were a result of sudden si gra and disloca- 
= a potas from sige Ap wie In be on p- 181, (1847,) 
rs the ark: ‘ We see that oa ee 1 pressure "exerted 
such 
ee beri see of the systems in the trends 
of feature lines over the globe—is seat _— in the articles re- 
aie aa but I a it by for the p 
e to bring the above » Aeciples under consideration 
with! ne erence to making such changes as may now be neces- 
take p, first, the question as to whether apie ey of 
level, that | qe subsidences and elevations, have been made by the 
ateral pressure resulting from contraction, as is nana in my 
Writings on the subject and those of most other authors ;—and 
ow was the lateral thrust from the direction of the oceanic 
morphism, igneous eruptions, volcanoes, the earth’s interior, 
and the origin of oceanic basi 
