82 Hayes and Campbell—Appalachian Geomorphology. 
axes of post-Cretaceous oscillation have also been lines of Paleo- 
zoic movement. 
A second and more clearly defined axis of elevation, O P, is 
found crossing the province in the vicinity of Chattanooga. Its 
trend is nearly due north and south, and it has been traced nearly 
as far north as Cincinnati. If the axis be continued across the 
Ohio river it falls in line With the eastern branch of the Cincin- 
nati arch passing through Findlay and Toledo, Ohio. This also 
may be only a coincidence, but it strongly suggests genetic con- 
nection between the portions of the axis north and south of 
Cincinnati. 
The third and most prominent of the transverse axes crosses 
the southern portion of the province, passing near Atlanta and 
forming a tangent to the great northwestward bend of the Ten- 
nessee river. It was first recognized by McGee in studying the 
sediments of the southern Atlantic coastal plain and Mississippi 
embayment. He describes this ‘ Charleston-Memphis axis” * 
as an axis of maximum subsidence during both low level periods 
(represented by the Lafayette and Columbia formations) and an 
axis of maximum uplift during both high level periods. It is 
represented on the map by the broken line 4 B, haying a nearly 
east-and-west direction ; it intersects the last described north- 
and-south transverse axis as well as the longitudinal axes, and 
since, as shown by the contours, it is at present a line of depres- 
sion the effect of the elevation along the other axes is wholly 
or partially neutralized at their intersections. The oscillations 
on this axis A B have been an important factor in determin- 
ine the drainage of this region and will be again referred to in 
the second part of this paper. 
The probability of orogenic forces having been active upon 
the transverse axes during Paleozoic time was mentioned above. 
In case of the axis A B, there is proof of such activity at two or 
more distinct epochs. In mapping the Paleozoic formations of 
northern Georgia and Alabama it was found that two terranes 
which present strong indications of having been deposited under 
shore conditions terminate abruptly against this line. These 
shore formations are the Birmingham breccia at the top of the 
Knox dolomite and the Oxmoor sandstone occurring in the 
lower Carboniferous. Other stratigraphic changes scarcely less 
* The Gulf of Mexico as a Measure of Isostacy (abstract), by W J McGee: 
Bull. Geol. Soc. Am., vol. ili, p. 503. 
