JOHNSON: TALLULAH DISTRICT. 
227 
the quartzite beds. This seems justifiable inasmuch as the beds 
of quartzite, slate, and limestone are apparently parallel to the foli¬ 
ation of the schists, as are also the included bands of gneiss. In 
his report Mr. Jones speaks of the foliation as making a marked angle 
with the limestone belt, but he has since informed me that this con¬ 
clusion was not based on his own observation. The evidence of 
numerous sections seen in all parts of the field leads me to believe 
that the foliation has not obliterated all traces of the former bedding, 
but that foliation and bedding are approximately parallel. 
In connection with the local geology it remains to emphasize the 
fact that the quartzite of the Tallulah Gorge is wholly distinct from 
the mica schist. Mr. Jones has considered the two rocks as practi¬ 
cally identical, one being merely a weathered phase of the other, and 
has represented them by one pattern on his geological sketch map. 
It is true that the quartzite and mica schist grade into each other, just 
as a sandstone may grade into a limestone by gradual change in 
composition. But the mica schist is no more a weathered phase of 
the Tallulah quartzite than is the limestone a weathered phase of 
sandstone. Fresh quartzite is found from the bottom to the top of 
the gorge below the falls, and mica schist is found from the surface 
railroad cuts to the bottom of the various gorges. Gradations from 
quartzite to mica schist may be found in the same ledge in certain 
cases, but the change is independent of weathering. The weathering 
of the quartzite is distinctly different from that of the schist, and 
has seldom penetrated far into the rock, even on the upland surface, 
unless the quartzite has been strongly sheared. Where the latter is 
the case, the effect of the shearing is plainly visible in the fresh rock, 
giving a parallel gneissoid texture, which does not become much 
more prominent with discoloration and weathering. The very pro¬ 
minent foliation of the mica schists can in no case be correlated with 
the weathered phases of the quartzite. 
This point requires special emphasis, since the fact that the Tallu¬ 
lah River has its lower course across a dense, resistant quartzite, 
while all the other streams are located almost entirely on weak mica 
schists, furnishes the key to the development of certain topographic 
features in the district. The failure to recognize this point has here¬ 
tofore made it impossible to solve certain of the problems presented, 
and has led to unnecessarily complicated interpretations of the method 
of capture. 
