516 



C. SCHUCHERT PALEOGEOGRAPHY OF KORTH AMERICA 



The systems or periods are delimited by diastrophic conditions that as 

 a rule are also worldwide. Each period is marked by a new transgression 

 of the oceans invading the lands. These are usually slow in progress and 

 of long duration, yet are followed by a more rapid withdrawal of the conti- 

 nental seas. Theoretically, the periods are separated from one another by 

 the two highest successive nodal points of emergence on the curve chart ; 

 practically, however, it will not be easy to decide which of the definitely 

 localized formations of emergent times belongs to this or that period. In 

 some cases the faunas will determine this point, and in others the making 

 of paleogeographic maps. Where the seas have been continuous from one 

 period to the next, however, as on Anticosti, the line of separation must 

 either be an arbitrary one or be drawn on the evidence of faunas elsewhere 

 recorded by the oscillatory strand-lines. 



PALEOZOIC ERA (emended) 



Georgia Period (new) 



(Lower Cambrian, Georgian, or Olenellus epoch of Walcott) 



See plate 51, and pages 482, 483 



Table of Georgic Formations 



House range, Utah 



Mount Bosworth, 

 British Columbia 



Georgia, Vermont 



Smith sound, 

 Newfoundland 



Waleott, 1908 



Waleott, 1908 



Waleott, 1891 



Waleott, 1900 



Pioche shale 



Mount Whyth shale, 



Break 







125 



limestone, and 



oolite 



390 



Argillaceous shale 











3,500 



Break 



Prospect Mountain 











quartzite 











1,375 



Saint Piran shale 



and sandstone 



2,705 



Limestone and shale 

 1,700 







At Big Cottonwood, 











Utah 











11,750 + 





Quartzite 



Placent 



a shale, 



sandstone and shale 





50 



limestone, and 

 basal conglomerate 



900 + 



Waucoba Springs, 



Lake Louise shale 



Shale with thin 





Inyo countv, Cal. 



105 



limestone 





5,670 + 





3,500 





of sandstone, 





Georgia shale 





shale, and 





200 





limestone 



Fairview quartzite 



Basal limestone 





( J, 290) 



(500 + 



1,000 







