468 C. SCHUCHERT PALEOGEOGRAPHY OF NORTH AMERICA 



Adirondachia. — See Laurentia. 



Alleghania. — A narrow, slightly positive element extending from south- 

 ern Kentucky into New York, having the strike of the Appalachian folds. 

 It represents the western part of the Alleghany plateau of physiographers 

 (Lippincotfs Gazetteer, 1906: 44). During times of general inundation 

 it is probable that this area was a submerged bank, rather than a land. 

 It was the western edge of the subsiding Appalachian synclinorium, and 

 probably had its origin at the time of the Cincinnati uplift. 



Antillia. — This element embraced the Greater and Lesser Antilles and 

 the Bahama islands. If there is any Paleozoic sedimentary history of 

 this region it is unknown, but all writers treating of this subject agree in 

 assuming that during the Paleozoic this region was land. Willis 83 regards 

 it as the southern extension of Appalachia, the view also of Freeh, 84 who 

 calls it "Paleoappalachia." At different times, however, Antillia appears 

 to have been separated from Appalachia by Suwanee strait, as indicated 

 by the distinct Atlantic faunas that enter the Mexico embayment during 

 this time. This fact furnishes the necessity for tlje term Antillia. 



Appalachia. — This name has long stood for a marginal positive ele- 

 ment of very ancient origin, comprising most of the Atlantic states from 

 southern New Jersey to eastern Alabama. While land had existed in this 

 area continuously since the Cambric, there is no evidence that Appalachia 

 was subjected to the same amount of elevation as Acadia. However, the 

 middle and southern portions apparently extended far into the Atlantic 

 during the Paleozoic — a condition maintained during the greater part of 

 Mesozoic time by the decided rejuvenation of Appalachia during the 

 Appalachian revolution. In the north the Atlantic repeatedly crossed 

 Appalachia, and in the Ordovicic had a short embayment down what is 

 now the Piedmont plateau to southern Virginia. Appalachia, being a 

 bordering positive element, was nevertheless devoid of volcanic activity 

 during the Paleozoic, as far as its present area is concerned. While this 

 fact is in harmony with what is known regarding most of the lands con- 

 tiguous to the Atlantic ocean, yet as Appalachia was subjected to much 

 lateral pressure during the late Paleozoic it seems as though some volcanic 

 action must have then existed. Does this condition signify that Appa- 

 lachia extended farther into the Atlantic than is generally supposed? 



Appalachia was first defined by Dana in 1856. 85 He states : 



83 Willis : Bull. Geological Society of America, vol. 18, 1907, p. 394. Journal of Geol- 

 ogy, Chicago, vol. 17, 1909, p. 206. 



84 Freeh : Letham geognostica, 1901. 



85 Dana : American Journal of Science, vol. 22, 1856, pp. 319, 344. See also Manual of 

 Geology, 1874, p. 150. Bull. Geological Society of America, vol. 1, 1890, p. 36. Manual 

 of Geology, 1895, p. 443. 



