212 The American Geologist. April, i90i. 
as a rule, carries microscopic inclusions. Quartz, with occas- 
ional grains of feldspar, are common in drop-like inclusions 
in the larger feldspar individuals. Micropegmatitic inter- 
growths of quartz and feldspar do not fail entirely in thin sec- 
tions of the granite-gneiss, but are less frequently met than in 
the massive granites. 
A second area of similar highly contorted gneiss begins 
in Troup county in middle southwest Georgia near the Ala- 
bama line, and crosses Meriwether county in an east-west 
course. Hand specimens of the rock from the two areas are 
indistinguishable and are identical in mineral and chemical 
composition. 
The other areas of gneiss are strongly contrasted, and var}'- 
in degree and regularity of the foliated structure, and in color 
and texture. The relationships, while not entirely clear in the 
field, possibly suggest that several of the areas may be the 
transitional foliated phases of the massive granites, but so far 
as the writer's observations extend, the conditions strongly 
point to no gradation of the typical gneisses into the equivalent 
massive rocks. They are all, however, biotite granites with 
the same minerals present in nearly similar proportions. This 
fact is further corroborated in the table of analyses where the 
rocks are seen to be nearly identical in composition. (See an- 
alyses XVI, XVII, XVIII, XIX, XX, XXI, XXII, and XXIII 
Table A.) 
That the schistose or foliated structure is entirely secondary, 
resulting from pressure metamorphism, and not primary, is 
plainly manifested in the thin sections of these rocks. The 
f|uartz and feldspar grains are invariably rimmed by crushed 
zones of the two minerals ; the quartz extinguishes irregularly ; 
and numerous lines of fracture are common to both quartz 
and feldspar. The Lithonia area of contorted gneiss, how- 
ever, affords but slight if any evidence of peripheral shattering, 
which likely indicates recrystallization of the minerals through 
profound metamorphism. 
