1916.] NATURAL SCIENCES OF PHILADELPHIA. 101 



The more interesting generalizations drawn from the physiographic 

 summaries are the following. Northward numerous species, charac- 

 teristic of the Piedmont in the area here treated, pass to the Coastal 

 Plain of that region, frequently, or rather generally, leaving the 

 Piedmont. The explanation of this is apparently temperature 

 control and the distribution is typical of the Upper Austral life-zone. 

 Toward the southern end of the Piedmont region numerous forms, 

 characteristic of this section in the Carolinas, enter the lower moun- 

 tains, doubtless as valley intrusions; this also can be explained by 

 temperature control and is zonal in character. Along the coastal 

 side of the Piedmont in Georgia, a number of Coastal Plain species 

 penetrate the Piedmont for considerable distances to points such 

 a- Warm Springs, vicinity of Stone Mountain, Thompson's Mills, 

 Toccoa and even to suitable situations on the slopes of Currahee 

 Mountain, an outlying knob near Toccoa. This is quite marked 

 in the case of Warm Springs, which has seven species of this category 

 occurring there. 2 The extending influence of the larger river valleys, 

 such as the Savannah, Oconee, Ocmulgee, Flint and Chattahoochee, 

 is doubtless responsible for these intrusions, for such they are is 

 evidenced by the known distribution of the species elsewhere and the 

 generic habitat. The division of the Coastal Plain into two areas 

 has abundant evidence in its favor in the Orthoptera, as the tabula- 

 tions show. It is significant also that quite a few of the forms 

 do not reach into peninsular Florida. Further studies on the dis- 

 tribution of central Florida forms of the orders will doubtless throw 

 much additional light on the fixity of these limitations. It is possible 

 that a lack of material may be partly responsible for the apparent 

 restriction of these ranges. In the case of the divisions of the Coastal 

 Plain, our material is sufficiently full to show the correlations very 

 clearly. 



Life Zones. 



The life zones represented in the area studied are the following: 



a. Boreal or Canadian. 



b. Transition or Alleghanian. 



€. Upper Austral or Carolinian. 



d. Lower Austral or Austroriparian. 



e. Basic Austral or Sabalian. 3 



2 These are: Cariblatta luleahdea (also Thompson's Mills), Radinotatum brevi- 

 penne brevipenne, Scirtetica marmorata picta, Eotettix pusillus, Hesperotettix 

 floridensis, Atlanticus gibbosus (also on Currahee Mountain) and Cryptoptilum 

 trigonipalpum (also vicinity of Stone Mountain). 



3 For remarks on this zone see p. 104. 



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