98 



INDEX TO THE STEATIGRAPHY OF NOETH AMERICA. 



A somewhat different development of Safford's Ocoee group is found in extreme 



southwestern North Carolina, as shown by the following section : 



Generalized section of the sedimentary rocks of the Nantahala quadrangle. ^^ 



J 11-12. CALIFORNIA, NEVADA, AND UTAH. 



In 1890, with reference to the Great Basin province in general, Walcott^^ 

 summed up the Cambrian stratigraphy as follows : 



In this province there appears to have been a large accumulation of more or less coarse, 

 arenaceous sediment, commingled with considerable argillaceous material, before the deposition 

 of the sediments of the OleneUus zone. As far as shown, the Olenellus fauna appeared at the 

 time the character of the sediments was changing to finer sands and argillaceous clays, and 

 then to calcareous clays. The sedimentation is unhke that of the sections on the eastern side 

 of the continent. The southern portion of the province is found in the Great Basin region of 

 Utah and Nevada, between the Wasatch range and the Sierra Nevada range. In the eastern 

 or Wasatch area Lingu[l]ella ella, Olenellus gilherti, and Cruzianasp.? occur in a thin band of 

 fine micaceous sandstone, about 200 feet from the summit of the Cambrian rocks, which are 

 conformably subjacent to strata of Ordovician age. The OleneUus-bearing sandstones are 

 covered with trails of annelids, etc., and are evidently a littoral or shore deposit. 



