OOZ C. SCHUCHERT PALEOGEOGRAPHY OF XORTH AMERICA 



In the Arctic archipelago there is no clear evidence of Mississippic 

 faunas, yet on Feilden peninsula (latitude 82 degrees 43 rninntes) species 

 are cited suggestive of this time. The evidence for the Tennesseic and 

 Pennsylvanic is much stronger. 



According to D. "White, the plants of the lower coal beds about cape 

 Lisburne, Arctic Alaska, indicate the Mississippic and of a time "slightly 

 younger than the Ursa flora/' Above is a marine series with corals, 

 rather suggestive of the early Pennsylvanic. 



Tennesseic Period (new: Ulrich) 



(Upper Mississippian or Saint Louis and Chester of geologists) 



See plates 81, 82, and pages 495, 496 



The emergence at the close of the Mississippic blotted out the Cordil- 

 leran sea of wide extent, and no deposits of Tennesseic age are as yet defi- 

 nitely known here except possibly in the Arctic region. The Baird or Pvo- 

 iluctus giganteus fauna is referred to the Pennsylvanic. The best known 

 area of Tennesseic sediments is that of the Mississippian sea, where the 

 greatest thickness is apparently not in excess of 1,200 feet. It is probable 

 that in no part of the latter sea did its waters persist from the Mississippic 

 into the Tennesseic, yet apparently the Keokuk emergence was of very 

 short duration. "With the introduction of the Saint Louis transgression 

 much change in the life took place. The crinoids no longer are present 

 in vast numbers and species; the echinoids (Melonites) are much larger 

 and dominate the Meramecian; Pentremites was previously of rather rare 

 occurrence, but now becomes more abundant and larger and is one of the 

 dominant types of invertebrates, especially in the Chesterian ; the Bryozoa 

 of the family Fenestellidae, having thickened supporting parts, as Archi- 

 medes and Lyropora, are prolific in numbers and species, especially in the 

 Chesterian. Of brachiopods, Cleiothyridina, Eumetria, and Dielasma 

 are dominant, large spirifers like S. logani are absent, while Atliyris, 

 Camaroplioria, Chonetes, and Syringothyris are rare or wanting. Among 

 the corals, Litlwstrotion, or rather, Axinura, apparently originates here; 

 certainly those with large corallites begin at this time and are dominant 

 in the Meramecian. 



The emergence terminating the Tennesseic Avas a complete one in the 

 area of the Mississippian and Appalachian seas, while that of the Cordil- 

 leran sea was absent throughout this period. In the Oklahoma basin, 

 however, the Chesterian sea may have continued unbroken into the Potts- 

 villian. It also seems to be true that the seas of Pennsylvanic time 

 appeared somewhat earlier in the Cordilleran and Californian than in the 



