20 HARPER 



comprises about 22% of the area of South Georgia, and 

 its average altitude is about 100 feet above sea-level. The 

 Altamaha Grit or some phase of it probably underlies all the 

 flat pine-barrens, but as it is everywhere covered to such a 

 depth with Lafayette and Columbia that no rock outcrops are 

 known, and the topography is appreciably different, it seems 

 best to keep the flat country apart from the typical Altamaha 

 Grit region for the purposes of the present discussion. 



Pinus palustris is the prevailing tree in this as in other pine- 

 barren regions, and the whole flora is a good deal like that of 

 the Altamaha Grit region, but probably not so rich, on account 

 of the less diversified topography. 



10. Littoral Region. Lastly there is the maritime or littoral 

 region, including the islands and marshes along the coast and' 

 part of the mainland of the six maritime counties. Little is 

 known of its geology except that the surface is all of the Columbia 

 formation (mostly sand but sometimes clay), or recent alluvium 

 along the rivers, while the Lafayette is either absent or buried 

 out of reach by younger formations. 



Pine-barrens are not typical of this region. Sand-dunes, salt 

 and brackish marshes, and dense forests of live-oaks and other 

 angiospermous evergreens are more common. Sabal Palmetto 

 is a characteristic tree. The phytogeographical features do 

 not differ conspicuously from those described by Kearney on 

 the coast of North Carolina, Coker in South Carolina, Mohr in 

 Alabama, and Lloyd and Tracy in Mississippi and Louisiana. 



