THE 
AMERICAN NATURALIST. 
VoL. x1.— JULY, 1877. — No. 7. 
NOTES ON THE AGE AND THE STRUCTURE OF THE 
SEVERAL MOUNTAIN AXES IN THE NEIGHBORHOOD 
OF CUMBERLAND GAP. 
BY N. S. SHALER. 
THE dogma of De Beaumont as to the parallelism of mountain 
chains of the same age has not lost its effect on the minds of 
geologists. The exceeding ability and untiring persistency with 
which its fallacies were urged has made it necessary to do more 
than refute them. Every instance of distinct contradiction 
should be well attended to and brought to the attention of natu- 
ralists. Having been trained in the theory of De Beaumont, I 
confess to having held to some remnant of faith in his views until 
I began my studies on the Appalachian system of mountains. 
aving examined this system in a preliminary way, throughout 
its extension from Gaspé to Georgia, I am convinced that as far 
as we can base our conclusions on the structure of, one mountain 
system, it would be nearer the truth to say that mountain sys- 
ems are more likely to be the product of parallel upheavals 
occurring in successive geological periods than of single epochs 
of elevation. 
Some years ago I called attention to the fact that the Cincin- 
hati axis was an outlier of the Appalachian system, and that it 
was formed, in part at least, as far back as the calciform sand 
rock of the Upper Cambrian period; also that the syenite 
axis on which Richmond, Virginia, now stands was uplifted after 
the general elevation of the Alleghanies had taken place,' since 
the formation of the Richmond coal-basin, and therefore must 
be referred to a time subsequent to the Trias if not to the Lias. 
The Blue Ridge was certainly elevated, at least in part, before 
have since found that the parallelism of the Cincinnati axis with the Appa- 
1 
lachian system had been previously noticed by Prof. J. M. Safford, State Geologist of 
Tennessee, : 
(Been eee EREET E ASEEN 
Copyright, 1877, by A. S. PACKARD, JR. 
