286 F. H. Bradley—=Silurian age of the Southern Appalachians. 
nearly parallel with the inclosing strata, in consequence of 
schistose structure especially favorin splits i in that direction. 
At many points, they look like regularly interstratified beds. Con- 
ditions have here favored most thorough metamorphism, proba- 
bly by reason of a more open and porous condition of the 
material, erchtie 3 more abundant percolation of the heated 
mineral waters. The wall-rock, at some points, is of the 
toughest "psoas _quartayte; at others, a micaceous gneiss ; 
again, a tremolyte or hornblen nidyta: Both the walling and 
“horses” of the same material are often permeated with copper, 
iron and zine sulphids. The true gangue is quartz, at some 
points very abundant, at others scarce. 
Passing on from this belt, the southeast dips bring in again 
the schists and gneissoid conglomerates of the Ocoee, and the 
gneisses and gneissoid quartzytes of the Chilhowee and the 
Knox sandstones. Above this latter bed, which is here, of 
course, undistinguishable from the Chilhowee, the Knox shale 
is represented by fine-grained blue mica slates speckled with 
mica crystals; and, within a quarter of a mile of Murphy, we 
find the Knox dolomyte, in white, speckled, gray, dove-colored 
and nearly black marbles ese materials being so much 
more easily eroded and dissolved than most of the quartzose 
rocks, have caused the formation of a long line of valleys, and 
are themselves generally covered. Before treating of them in 
detail, or passing on to more easterly outcrops, let us review 
the strata along another line of approach. 
4, From Knoxville to Murphy. 
At Knoxville, just north of the railroad track, a line of fault, 
essentially the equivalent of, and probably continuous with, 
that noticed just southeast of ‘Athens, separates the upper shales 
of the Cincinnati group from the Knox dolomyte, both having 
southeast dips. The = tebe with its characteristic cherts and 
sandstones, forms the ridge upon which the main part of the 
city of Knoxville stands, and extends across to the south bank 
of the Holston, where it is regularly overlaid by the shaly lime- 
stones of the Chazy, the fine quarry-marbles of the Trenton, and 
the shales and iron-limestones of the Cincinnati, which latter 
marble.” The nae in successive waves, Ae occu- 
pies the surface nearly to Rockford—say for six miles—and 
then yields place to the ro dolomyte, which continues to be- 
yond Maryville. This town, sixteen miles fro m Knoxville, 
stands near the crown of a low arch, which a woaeais to be the 
uivalent of the sharp anticlinal in the valley southeast of 
White Cliff, though here somewhat farther out from the main 
