NEGATIVE CONTINENTAL ELEMENTS 483 



medial Texas. As its faunas were those of the Pacific realm, it must have 

 had connection with that ocean across Baja California. The Sonoran sea 

 was often in communication with the Cordilleran sea by way of the Ari- 

 zona basin, situated between the lands Ensenada and Utah. In the Upper 

 Devonic especially, but also in the Mississippic and Pennsylvania this sea 

 had a northern extension across western New Mexico and eastern Arizona 

 and reaching into western Colorado; this may be known as the Ouray 

 basin. The Devonic faunas of this basin were different from those of the 

 Cordilleran sea. 



At certain times during the Cambric and the Ordovicic, the times of 

 wide Pacific inundation, the Sonoran sea was in open communication with 

 the Mississippian sea. Subsequently, however, these two seas were sepa- 

 rated by a greatly lengthened expanse of land. 



Suwanee strait. — During the Eocene, Oligocene, and Lower Miocene 

 central and southern Florida appeared as an island. The waterway be- 

 tween insular Florida and Appalachia, connecting the Atlantic and the 

 Gulf of Mexico, Dall and Harris have named "Suwanee strait." The same 

 opening undoubtedly existed during the Cretacic, but there is no evidence 

 of it across Antillia- Appalachia until the time of the Lower Devonic. 

 From thence into the Cambric the southern Mississippian sea again and 

 again had faunas that are Atlantic or Poseidon in their origin. On this 

 evidence rests the separation of Appalachia from Antillia in order to per- 

 mit the Poseidon faunas passage across Florida into the Mississippian sea. 



Sea of Tehuantepec. — At present North America and Central America 

 are bound together by a narrow strip of land, the passes of which are not 

 high above the sea. The geology of this region is known only along gen- 

 eral lines. Honduras appears as an ancient land nucleus, to the north 

 of which, in Guatemala and Chiapas, occur Pennsylvanic and Meso- 

 zoic deposits. As most of Mexico north of southern Oaxaca seems to have 

 been land during the Paleozoic, and as certain of the faunas of the Missis- 

 sippian sea must have entered the Mexico mediterranean across the syn- 

 cline of Guatemala, this marine thoroughfare may be named the Sea of 

 Tehuantepec. 



Traverse basin. — See Mississippian sea. 



Vancouverian sea. — This comprises the Pacific extensions across British 

 Columbia, the character of which is that of an interior continental sea. 

 The eastern edge of the land bounding it on the west seems to be repre- 

 sented by Queen Charlotte islands. Dawson 73 regards the area of this sea 

 as a syncline ; therefore there should be a land to the west parallel to Cas- 

 cadia. For the present the definition of this bordering continental sea is 



73 G. M. Dawson : Bull. Geological Society of America, vol. 12, 1901, p. 73. 



