NEGATIVE CONTINENTAL ELEMENTS 455 



Great Plains basin. — See Coloradoan sea. 



Hudson sea. — A very shallow continental V-shaped sea of enormous 

 •extent during Ordovicic and Siluric times, having wide open connection 

 with the Arctic ocean across Franklin archipelago, and by way of the 

 Dakota basin through the Cordilleran sea. During the Ordovicic there 

 ivas also free communication with the Atlantic by way of Baffin basin. 

 In southern Baffin Land are Middle Ordovicic faunas of the same aspect 

 as those of Akpatok island, in Ungava bay. Because these localities are 

 so near the present deep seaways of Hudson strait and Davis strait, it 

 seems reasonable to assume this Atlantic (Poseidon) communication. To 

 the south this wide sea narrowed between Ungava and Keewatinia; the 

 northern portion of this area may be known as James basin and the south- 

 ern part as Ontario basin. During the Middle and Upper Ordovicic these 

 basins communicated uninterruptedly with the Mississippian sea, but far 

 less openly with the Saint Lawrence sea. In the Siluric the southern 

 communications were continued, but the eastern opening was of short 

 duration. In the Middle Devonic the Mississippian sea occupied the 

 Ontario and James basins for the last time. 



Indiana basin. — See Mississippian sea. 



Iowa basin. — See Mississippian sea ; also Cordilleran sea. 



James basin. — See Hudson sea. 



Kansas strait. — See Mississippian sea. 



Kentucky strait. — See Mississippian sea. 



Knoxville trough. — See Appalachian sea. 



Lenoir basin. — See Appalachian sea. 



Levis channel. — See Saint Lawrence sea. 



Logan sea. — An extensive, late Jurassic, western continental sea of 

 very short duration, with northern Pacific connections. It extended from 

 northern British Columbia across northern Cascadia, thence southward 

 throughout the Eocky Mountain area into northern Arizona, and east- 

 ward into western South Dakota. This sea was correctly mapped by 

 W. N. Logan, 58 for whom it is named. 



Mackenzie basin. — See Cordilleran sea. 



Mediterranean refers to those deep extensive bodies of marine waters 

 situated between continents, with usually but one opening into an ocean. 

 These were also permanent seas, true negative elements, whose boundaries, 

 however, are changing more constantly than those of the oceans. The 

 Gulf of Mexico-Caribbean sea has been named by Krummel "the Ameri- 

 can mediterranean." See Poseidon ocean. 



58 Logan : Journal of Geology, Chicago, vol. 8, 1900, p. 245. 



