RECOGNITION OF CHARACTER OF SOILS. 495 



herbaceous vegetation consists exclusively of very small-seeded, 

 " calcifuge " plants (sedges, orchids, Juncus, Hsemodoraceae, 

 Xyris, Polygala, etc.). This land is wholly unproductive and 

 affords but indifferent pasturage, except the first season after 

 burning-over; probably because of the effect of the minute 

 amount of ashes so added. As the coast is approached, the 

 clay subsoil has an increasing depth of sandy soil-mass above 

 it, and on these " sand hammocks " the long-leaved pine grad- 

 ually assumes more and more of its usual stature ; the cypress 

 disappears, and the Cuban pine (here called pitch pine) grad- 

 ually comes in; while the sedgy vegetation diminishes and 

 finally disappears. On this land crops may be grown as in the 

 long-leaf-pine uplands. 



But on the immediate coast, evidently under the influence of 

 the aboriginal " shell mounds," the yellow sandy soil becomes 

 blackish from the (humus-forming) effect of the lime thus 

 supplied; and concurrently the coast liveoak (Q. virens}, grape 

 vines, the Hercules club (Aralia spinosa), " 1'herbe a trois 

 quarts' (Verbesina sp. ), and numerous leguminous plants 

 (which are wholly absent from the pine meadows) take pos- 

 session of the land, which is very productive and has been 

 specially utilized in the growing of Sea Island cotton. Here 

 the clay stratum is 15 to 20 feet below the surface, and roots 

 penetrate to great depths in the pervious soil, whose great 

 thickness makes up for its low percentage of plant-food (see 

 table below). This land is distinctly limited by the extent of 

 the shell heaps, past or present, and shows a respectable per- 

 centage of lime. 



PINE MCAOOW5 SANtnVMUOCKS' SEAT51ANO 



FIG. 78. Schematic profile of the Mississippi Coast Belt, through Jackson County. 



The annexed schematic profile (fig. 78) illustrates these 

 changes of soil and vegetation, which furnish a striking ex- 



