The lie;/ /'on About Atlanta, Georgia. — Purington, 105 
Texas Cretaceous is clear enough without explanation. It 
differs mainly from the table published by Mr. Hill in group- 
ing the Caprina limestone of his Fredericksburg division with 
the Washita division, and in the addition of the Jurassic 
formation in Texas. I shall publish, by and by, a histor} 7 of 
the Texas Jura. 
GEOLOGICAL AND TOPOGRAPHICAL FEATURES 
OF THE REGION ABOUT ATLANTA, 
GEORGIA. 
By Chester Wells Purington, Boston, Mass. 
(Plate IV.i 
During the past winter opportunity came to me, while in 
the vicinity of Atlanta, Georgia, to make a few observations 
on geological features of the region which appear to deserve 
notice. 
As may be seen, by reference to the accompanying map, 
forming figure 1, plate iv,* central Georgia is a region of crys- 
talline rocks, gneisses and schists for the most part, in eon- 
tact on the northwest with Paleozoic rocks, and overlain on 
the southeast by the superimposed beds of the Cretaceous and 
Tertiary. .Although little has yet been done in the way of 
attempting to correlate this area with others, it is safe to say 
that these gneisses and schists are of Archean age, in the 
broader use of the term. Indeed, it is probable that the rocks 
about Atlanta belong to that limited and lowest division of 
geologic time to which the more restricted term Archean lias 
recently been applied. 
The region is one where much erosion lias taken place, and 
the red clays and soils resulting from the disintegration of the 
rock lie undisturbed over the gneiss. The red soils are famil- 
iar to all who have been in the southern Appalachians. They 
have been well described by Russell. f The products of decay 
are in some places fifty feet thick, as can be well seen in deep 
*Prepared from the bulletins of the United siatrs Geological Survey, 
containing the correlation papers of the Archean, Cretaceous, Eocene, 
and Neocene; and from Prof. .1. W. Spencer's report on the Paleozoic 
group of ( leorgia. 
fSubagrial decaj of rocks, and the origin of the red color of certaiu 
formations; bv Israel Cook Russell. Bulletin 52, I'. S. Geol. Survev. 
