28o FLORIDA GEOLOGICAL SURVEY SIXTH ANNUAL REPORT. 



12. BELLAIR SAND REGION. 

 (FIGURES 74, 75) 

 References — Nash (101,107) and U. S. soil survey of Leon Co. 



This embraces about 250 square miles in Leon and Wakulla 

 Counties. In the Third Annual Report it was treated as a part 

 of the peninsular lime-sink region (described farther on) ; but as 

 it is entirely disconnected from that, and differs somewhat in veg- 

 etation and other characters, it is now described separately. 



Geology and Soils — The whole area seems to be underlaid by 

 II limestone of Oligocene age, which crops out occasionally 

 through the surface sands in boulder-like patches a few square 

 feet in area and a few inches high, usually too small to have any 

 vegetation on them. This type of rock outcrop (namely, calcare- 

 ous rocks surrounded by sand) is not found in any of the regions 

 previously described, but it is rather common in some parts of the 

 Florida peninsula. Such outcrops are not found on every square 

 mile, however, and they constitute only an infinitesimal fraction 

 of the whole area. Some excavations in the neighborhood of 

 ponds and streams have disclosed a pale reddish sandy clay, sim- 

 ilar to that in various other long-leaf pine regions, but it seems 

 never to approach the surface nearer than a foot or two, and at 

 present there is no way of knowing just how extensive it is. 



The prevailing surface material is a pale buff loamy sand 

 from one to several feet deep,* remarkably homogeneous 

 throughout except that the uppermost few inches, influenced by 

 the vegetation, are of course a little grayer. It is of rather fine 

 texture in Leon County, but a little coarser in Wakulla. In some 

 places where the ground-water is nearer the surface the sand is 

 firmer, and the vegetation considerably different. 



The deep dry sand is called "Sandhiir'f in the government 

 soil survey of Leon County, and the mechanical analyses of it in 



*Some railroad cuts ten feet deep do not reach the bottom of the sand. 

 On account of the character of the soil, this region, like other very sandy 

 regions (the northern part of the lower peninsula of Michigan, for example) 

 is traversed by a maze of ill-defmed, "heavy" and changeable roads. But in 

 a few places the underlying clay has been dug out and used for surfacing the 

 roads, with very satisfactory results. 



tNearly all the other areas hitherto dressed as "Sandhill" by the U. S. 

 Bureau of Soils are along the fall-line in North and South Carolina (the 

 same type is also extensively developed in Georgia, but not yet mapped by 



