OCKLOCKNEE AND AUCILLA RIVERS. 
129 
GENERAL CONSIDERATIONS. 
DIRECTION AND COURSE OF STREAMS. 
With regard to drainage, one of the striking features in this 
area is the prevailingly northeast to southwest course of the prin¬ 
cipal streams. The Ocklocknee, St. Marks and Aucilla rivers are 
approximately parallel, flowing from the northeast to the southwest. 
Why these streams should have taken this course is unexplained, 
unless possibly they follow minor original troughs or synclines, 
which seems possible. The course of the Ocklocknee in particular 
suggests that it may have flowed along the west side of a northeast 
southwest ridge until passing around the point of the ridge, when it 
turned southeast to the Gulf. This suggested structure, as indi¬ 
cated by the course of the streams, has not been sufficiently estab¬ 
lished from the surface exposures of the. rocks. 
Contour lines at 25 foot intervals. 
A second striking feature about the drainage is the fact that 
practically all tributaries to the main stream enter from the west or 
northwest side. The direction of flow of tributary streams being 
from the northwest to the southeast. Few or no tributaries of any 
considerable size enter the stream from the east side. This fact is 
readily understood. The. minor streams follow the dip of the for¬ 
mations, which in the main is to the southeast. Not only do the 
surface streams follow and flow with the dip, but the ground water 
likewise probably follows the dip of the formations. Many of the 
small streams originate in spring heads. The migration of these 
