452 C. SCHUCHERT PALEOGEOGRAPHY OF XORTH AMERICA 



it merged into the Mexico embayment. The Paleozoic deposits of this 

 basin are not so thick as those of the northern area. 



In the Ordovicic the eastern part of the Cumberland basin was occupied 

 by two distinct faunal elements, the western one of which contained the 

 life of the Mississippian sea, while the other derived Atlantic (Poseidon) 

 faunas through the Mexico embayment. The most easterly portion of the 

 Cumberland basin area has "been named Lenoir basin. 51 This basin was 

 again medially divided by "several disconnected longitudinal folds high 

 enough to affect the direction of currents, and consequently the character 

 of the sediments, and in a smaller degree faunal distribution. In a gen- 

 eral way the deposits may be divided into an eastern, Athens trough, and 

 a western series, Knoxville trough" (Ulrich and Schuchert, 1902, page 

 614). 



Arctic ocean. — Of all the permanent basins this ocean has had the least 

 effect, physically and faunally, on the North American continent. During 

 the Siluric, however, its waters attained a broad entrance into the United 

 States through the medial regions of the continent. In Middle and 

 Upper Devonic times its inundations were considerable, though less than 

 half those of the previous period, while in the Mississippic they were far 

 less effective. But once, subsequently, during the Cretacic, did this ocean 

 have free access to the continent through the Coloradoan sea. 



Arizona basin. — See Sonoran sea. 



Athens trough. — See Appalachian sea. 



Atlantic ocean. — Throughout the Paleozoic, and during most of the 

 Mesozoic, there was no Atlantic ocean in the sense of today. During the 

 vast time indicated above the North and South Atlantic were independent 

 bodies of water separated by Gondwana, uniting Africa and South Amer- 

 ica. For this reason it is not proper to speak of the Atlantic until after 

 late Mesozoic time, when the southern Atlantic, or Nereus, and the north- 

 ern Atlantic, or Poseidon, were more or less widely united. For further 

 remarks, see Poseidon ocean. 



Baffin basin. — See Hudson sea. 



Calif ornian sea. — A continental border sea of the Pacific across Cali- 

 fornia during the Paleozoic and Mesozoic. In the Triassic this sea ex- 

 tended to Nevada, Idaho, Oregon, and Washington. Like most continental 

 border regions, the Calif ornian sea was considerably affected by volcanic 

 deposits. These are known in Devonic, Pennsylvanic, and early Mesozoic 

 time. For the present this term has a very indefinite meaning. Walcott 52 



51 Ulrich and Schuchert: Rep. New York State Paleontologist, 1902, pp. 634, 644, and 

 map. 



53 Walcott : Proc. American Association for the Advancement of Science, vol. 42, 1894, 

 pp. 129, 145, with map. 



