3 28 1907 
No. 5.—DRAINAGE MODIFICATIONS IN THE TALLU¬ 
LAH DISTRICT. 1 
BY DOUGLAS WILSON JOHNSON. 
CONTENTS. 
LIBRARY 
NEW YORK 
BOTANICAL 
GARDEN. 
PAGE. 
Introduction.211 
Literature.214 
General geology.218 
General physiography . . . 219 
Geology of the Tallulah district 222 
Rock types.223 
Structural relations . . . 225 
Topographic features of the 
Tallulah district . . . 228 
The Tugaloo level .... 229 
The Chattahoochee level . 230 
The Chattooga escarpment 230 
The Tallulah and other 
mountain groups . . . 232 
Streams of the Chattahoochee 
drainage.232 
Streams of the Lower Tuga¬ 
loo drainage.232 
PAGE. 
Streams of the Upper Tuga¬ 
loo drainage.233 
Hanging valleys of minor 
tributary streams . . . 234 
The right-angled bend of the 
Chattooga-Tugaloo River 235 
Resum6.235 
Deductive study of river cap¬ 
ture .236 
Results of deductive study com¬ 
pared with facts observed 
in the Tallulah district . 241 
Evidence of the gravels . . 243 
Evidence of the shells . . . 244 
Alternative theories .... 245 
Summary.246 
Literature.247 
Introduction. 
In connection with the study of drainage modifications, the head¬ 
waters of the Savannah River have been frequently referred to as an 
example of drainage transferred from the Gulf system to the Atlantic, 
through the process of stream capture. The upper Savannah, known 
locally as the Chattooga River, flows directly southwest between 
Georgia and South Carolina to the westernmost point in South 
Carolina, there receiving the Tallulah River as a tributary from the 
northwest; it then turns abruptly southeast and continues, first 
under the name of the Tugaloo River and then of the Savannah 
River, to the Atlantic Ocean. Near the point where the river makes 
its peculiar bend to the southeast, there rises one of the headwater 
1 A Walker-prize essay, 1906. 
