JOHNSON: TALLULAH DISTRICT. 
217 
here cited does not seem entirely convinced of the process of capture 
as an efficient cause for the new order of things. Yet it is certainly 
significant that the gorge, unusual if not unique in sharpness of form 
among the southern Appalachians, should occur in immediate asso¬ 
ciation with a group of features whose systematic relations would 
seem to point unequivocally to the invasion of one river basin by the 
head branches of another. In view of the open form and gradual 
descent of the Chattooga valley in contrast to the narrowness of the 
Tallulah Gorge and the rapid descent of the river throughout it, one 
may reasonably conclude that the first was captured much earlier 
than the second. This makes it seem probable that the Tallulah 
formerly followed a course near the railroad line, and that its entrance 
into the Chattooga is the result of diversion by the headward growth 
of a creek on the line of the gorge; although a somewhat different 
opinion is expressed in the article here abstracted.’’ 
In the March number of the American geologist, for 1901, is a 
brief paper by S. W. McCallie on the “Trap dikes of Georgia,” accom¬ 
panied by a map which shows one such dike crossing the railroad a 
short distance south of Tallulah Falls. The dikes are described as 
generally having a vertical dip, and northwest-southeast trend, thus 
cutting across the crystallines which have a northeast-southwest 
trend. They are believed to be of the Jura-Triassic age. 
Professor T. L. Watson (’02, p. 63), in a report on the granites 
and gneisses of Georgia, published in 1902, gives a brief account of 
the geology and physiography of the Piedmont plateau of Georgia, 
and briefly refers to the reported capture in the Tallulah district. 
In a report on “River surveys and profiles made during 1903,” 
arranged by W. Carvel Hall and John C. Hoyt, and published in 
1905, a brief account of the Tallulah, Chattooga, and Tugaloo Rivers 
is given, together with lists of elevations and figures of profiles. The 
statement that “the Tallulah River crosses the fall line at Tallulah 
Falls” is erroneous, for the fall line is about one hundred and twenty- 
five miles farther southeast. 
In order to appreciate properly what follows, it is desirable to 
have clearly before us the general geologic and physiographic features 
of the Georgia-South Carolina region. To this end a brief review 
of the general geology and general physiography is first presented, 
after which the local details more intimately related to the problem 
of river capture will be discussed. 
