182 Geological Results of the Earth's Contraction. 
of favor the more closely it is applied, and we would fain believe 
that the following explanations will be found to secure it some 
additional attention. 
I. Folding of Strata.—tIn our last article on this subject, al- 
lusion was made to the foldings of the Appalachian strata, and 
from the fact that the plications were more abrupt, and the effects 
H. D. Rogers on the Appalachian chain for the details of the 
structure there presented.t 'These geologists have shown that 
the folds or plications are many and vast. Towards the south- 
east they are as closely compacted as is in any way possible, so 
that the annexed figure 4 is given as a just representation of it. 
To the northeast, the undulations become more and more gentle. 
Fig. 4. Fig. 5. 
Chai Wacitin: 
The following outline figure, though having too few folds, (fig. 
6,) will present some idea of their extent, and (in connection with 
figs. 4 and 5,) shows the characteristic forms of the plications, as 
ascertained by these able geologists. 
Fig. 6. 
3 
RW. 
From the Southeast actoss the Appalachians to the Northwest. 
Though the regularity is somewhat exaggerated, the general 
ts are not so. The surface of the country has since been 
lat 
on the scale here given—a diameter of a foot—actually corresponds to a mountai' 
twelve miles in altitude above the sea. It could not well have been made less 
resent the average height of the continents above the sea; for this height, accord- 
i, 1s somewhat less than a thousand feet, or, on the scale in the 
above figures, about a seventieth part of the elevation n. ' 
= 
gS 
a5 
c 
| 
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