104 PEOCEEDINGS OF THE ACADEMY OF [April, 



avenues of entrance to suitable environments in a region in general 

 characterized by a different fauna. The fact that these extensions 

 occur only, as far as known, at a few localities gives support to this 

 explanation. 



Lower Austral or Austroriparian. — This zone covers the area 

 situated below (i.e., in elevation) the Upper Austral, down to a line 

 extending from the southern portion of Pamlico Sound, North 

 Carolina, to Lake Waccamaw, North Carolina, to Yemassee, South 

 Carolina, then swinging in a curve to Albany, Georgia, and the 

 Chattahoochee River west of the last-mentioned locality. A few 

 forms, which we would consider more representative of the Upper 

 Austral zone, occur as stragglers within this area at localities such 

 as Goldsboro and Fayetteville, North Carolina, Sumter and Flor- 

 ence, South Carolina, Augusta and Macon, Georgia. It is possible 

 that future work may show these forms to be equally characteristic 

 of the Lower Austral; a very questionable possibility to our minds. 

 In these cases, the interdigitation which we have mentioned as 

 occurring at the upper limit of the Lower Austral is probably repeated 

 in the reverse direction, but physiographic control features are 

 probably responsible for these intrusions. 



Basic Austral or Sabalian.— -The present zone, which is co-extensive 

 with the physiographic area called Lower Coastal by us, we find is 

 so decidedly characterized by a considerable number of species, 

 which extend southward to southern or at least to central or north- 

 central Florida, that we have been compelled to give it a name. 

 We have found no term in the literature which we could use, so we 

 here propose the name Sabalian. The name has been derived from 

 the technical name of the cabbage palmetto (Sabal palmetto), 

 which is probably the most striking tree of the region named, and 

 whose distribution is co-extensive with that area. 



The Sabalian zone is characterized by at least six species, outside 

 of those occurring only in central and southern Florida, which are 

 also West Indian in distribution or extremely close to West Indian 

 species. 



The zone extends from the coast-line inland to the lower boundary 

 of the Lower Austral, given above in defining that region, north to 

 the region of Pamlico Sound and south into Florida. It is narrow 

 in the Carolinas, but becomes broad in Georgia and its exact extent 

 to the westward remains to be worked out. The exact line where 

 this same influence gives way to the Tropical in southern Florida 

 has not been critically mapped, owing to the need of more information 



