522 C. SCHUCHERT PALEOGEOGRAPHY OF NORTH AMERICA 



confirms the presence of Paradoxides in a fauna of thirteen species. This 

 fact shows how near the Atlantic waters approached those of the Pacific 

 realm on the western side of the Green Mountain barrier without inter- 

 mingling. Their present position, however, is due to much northwesterly- 

 thrusting. 



In southern Newfoundland, on Manuels brook, the Acadic begins with 

 a conglomerate having pebbles holding fossils of the Georgic strata below 

 (Walcott, 1900, 315). Above this layer, which is 18 inches thick, follow 

 argillaceous shales having a depth of 170 feet. These are succeeded by a 

 thin limestone zone marked by the presence of Paradoxides, the latter ex- 

 tending 66 feet higher in a series of shales interbedded with limestone. 

 Here occur Paradoxides davidis and P. oennetti. Apparently a strati- 

 graphic hiatus exists above these beds, followed by the Olenus fauna. 



The base of the Acadic of New Brunswick has the Protolenus fauna. 

 In the end this horizon may prove to be better placed at the top of the 

 Georgic. Its guide fossils are Botsfordia pulchra and the trilobites 

 Micmacca, Protolenus, and Bergeronia. 



The higher or Paradoxides beds here have, among others, an abundance 

 of Agnostus, Agraulos, Liostracus, Conocoryphe, Ctenocephalus, and Par- 

 adoxides (six species) ; also Protorthis hilling si. This fauna and the 

 other Atlantic biota are closely allied to the Paradoxides faunas of Wales 

 and Sweden but less so with that of Bohemia. 



Ozarhic (new: Ulrich) or Cambric (restricted) Period 



(Upper Cambrian, Saratogan. or Dikelocephalus epoch; in part, also, much of 

 the basal Ordovician of geologists) 



See plate 53, and pages 484, 485 



The type area for the faunal succession of this period is the Ozark 

 region of southern Missouri and northern Arkansas. Here the "Ozark 

 series" of Broadhead is divided by Ulrich 144 as follows : 



Jefferson City dolomite 50-250 feet. Eroded at the top. 



Roubidoux formation 70-225+ " 



Gasconade limestone 450-650 " 



Elvins formation 0-120 " 



In the Arbuckle mountains of Oklahoma, the Ozarkic, consisting of 

 limestones and dolomites, is not less than 4,000 feet thick. Ulrich states 

 that "it represents one of the longest uninterrupted depositions of pure 

 limestone and dolomite of which we have knowledge." The Ozarkic 



"* Bain and Ulrich : Bull. U. S. Geological Survey, no. 267, 1905, pp. 13-35. 



