GEOGRAPHY OF CENTRAL FLORIDA 



147 



clay loam. Old dunes with scrul) vegetation, mapped as "St. Lucie 

 sand" and "St. Lucie fine sand," make u^) a trifle more than a third 

 of the total. A few mechanical and chemical analyses are given in 

 the general chapter on soils. 



Fig. 34. Shell mound covered with tropical hammock vegetation and 

 partly excavated for road material, on east side of Indian River about oppo- 

 site Melbourne. The shells are nearly all Chionc cancellata, a small clam, and 

 there are many layers of humus in the mound. Feb. 4, 1915. (For a de- 

 scription and another view of the same place, taken a year or two later, see 

 J. F. Kemp, Econ. Geol. 14:311, pi. 5 b. 1919.) 



Vegetation. The flatwoods of the east coast differ from those 

 previously described in having more slash pine than long-leaf. The 

 old dunes (fig. 31 ) are generally covered with spruce pine and other 

 scrub vegetation much like that of the lake region, passing into 

 sandy hammocks where sufficiently protected from fire by the prox- 

 imity of water-courses, etc. In marly places there are large areas 

 of low hammock (fig. 29), passing into swamps where traversed 

 by streams. The dunes near the ocean have vast thickets of saw- 

 palmetto (fig. 33). Less extensive types are the palm savannas 

 on Merritt's Island (fig. t,2). and a little salt marsh and mangrove 

 sw^amp. The shell mounds are commonly covered with dense ham- 

 mocks of a decidedly tropical character. 



The commonest plants are listed below, but on account of the 

 indefiniteness of the inland boundary of the region in some places 



the sequence cannot be guaranteed as accurate. 



