THE 
AMERICAN GEOLOGIST. 
Vol. XXXII. OCTOBER, 1903. No. 4. 
SANDSTONE DIKES NEAR COLUMBUS, GEORGIA* 
By S. W. McCai.lie, Atlanta, Georgia. 
PLATES XXV-XXYIII. 
During the spring - of 1901 while making an examination of 
the banks of the Chattahoochee river south of Columbus for 
deposits of marls, my attention was attracted by fragments of 
sandstone strewn along the river banks, just above the water- 
level of the then swollen stream. These fragments were care- 
fully examined and found to be a rather fine-grained sandstone 
quite different from any rock occurring elsewhere in the vicin- 
ity. At the point where they were first observed no clue was 
given whatever as to their original source, but further down 
the stream where the banks became higher and where there 
were no alluvial deposits to obscure the natural formation, the 
Sandstone was to be seen in situ, forming the filling of what 
appeared to have been at one time open fissures or cracks in the 
Cretaceous clays. Owing to the high stage of the river at that 
time, it was found impracticable to make a satisfactory study 
of the occurrence of the sandstone and only a few general notes 
were taken. Later, a second, and. finally, a third visit was 
made to the locality and a more complete examination was 
made under more favorable river conditions. 
The location of these sandstone filled fissures, or what 
may be termed sandstone dikes, is on the Chattahoo- 
chee river, about fifteen miles south of Columbus, at what is 
known as Slick Bluff. The distance to which these dikes ex- 
tend along the river is about one mile. They appear to reach 
their maximum degree of development where the river banks 
* Published by permission of the State Geologist. 
