ALTAMAHA GRIT REGION OF GEORGIA 99 



The soil of a hammock is the same Columbia sand as on the 

 adjacent sand-hill, but mixed with more or less humus derived 

 from the more luxuriant vegetation. Whether the underlying 

 Lafayette is near enough to the surface in the hammocks so that 

 roots of trees can reach it I am unable to say, but if it is, this 

 would largely account for the nature of the vegetation. The 

 hammock soil must also contain more water than that of the 

 sand-hills, but it is never perceptibly moist at the surface (ex- 

 cept of course in rainy weather). The boundary between 

 sand-hills and hammocks is never very sharp, and it is altogether 

 probable that the hammocks are tending to encroach on the 

 sand-hills as the humus accumulates, just as the branch-swamps 

 are probably encroaching on the moist pine-barrens, as already 

 pointed out. Reasoning backward we may imagine a time, not 

 long after this region emerged from the sea for the last time, 

 when there were no hammocks at all. When we examine the 

 ranges of the plants we will find evidence in support of this 

 supposition. 



The following species are characteristic of hammocks in the Al- 

 tamaha Grit region. 



8 Quercus laurifolia 



3 



— 



9 Osmanthus Americana 





greenish 



7 Magnolia grandiflora 



5-6 



cream 



6 Ilex opaca 



4-5 



greenish 



5 Cornus florida 



3~4 



white 



5 Pinus glabra 



3 



— 



2 Cholisma ferruginea 



5 



white 



2 Mohrodendron dipterum 





white 



2 Persea pubescens 







2 Hicoria sp. 





— 



2 Quercus geminata 



4 



— 



i Ostrya Virginiana 



3-4 



— ■ 



i Pinus Taeda 



3-4 



— 



i Prunus serotina 



3-4 



white 



i Prunus Caroliniana 



3 



cream 



9 Batodendron arboreum 



5 



white 



8 Hamamelis Virginiana 



10-1 



yellow 



4 Vitis rotundifolia 



5 



cream 



4 Callicarpa Americana 



6- 7 



purple 



4 Asimina parviflora 



3-4 



dark purple 



3 Rhus copallina 



7-9 



cream 



3 Serenoa serrulata 



6 



cream 



3 Gelsemium setnpervirens 



3 



yellow 



3 Sebastiana ligustrina 



6 



greenish 



2 Parthenocissus quinquefolia 



5 



greenish 



i Symplocos tinctoria 



3-4 



cream 



