UPPEE CRETACEOUS. 703 



Q 7. UPPER YUKON, ALASKA. 



In 1905 Prindle and Hess ^^' reported the occurrence of a Cretaceous sandstone 

 in the Rampart region. ]\Iore recently Prindle ^'^° has revisited this locality and 

 found fossils assigned to the Upper Cretaceous. The rock in which this fauna 

 occurs is a black carbonaceous sandy argillite. Granitic rocks cut these beds, show- 

 ing a later intrusion of acidic rocks than was previously known. The areas are too 

 small to show on the map. 



(See also Q 7, Chapter XIV, pp. 635-636.) 



Q 8. NORTHERN YUKON TERRITORY. 



According to Camsell,^^*" Peel River, which flows northward from the Rocky 

 Mountains in Yukon Territory to the Mackenzie Delta, emerges from a lower canyon, 

 cut across folded slates of supposed Devonian age, and thence to a tributary called 

 the Snake — 



cuts a deep valley 500 to 700 feet in soft shales and sandstones of Cretaceous age. A section 

 of the bank * * * shows about 200 feet of yellow and red shales, which toward the base 

 are interbedded with layers of sandstone, resting on massive sandstone 50 feet in thickness. 

 * * * Farther downstream the banks consist principally of sandstone, with thin beds of 

 shale interposed between sandstone beds. In parts the sandstone contains concretions, many 

 of which are 10 feet in diameter. Apparently the river in this portion cuts through a low anti- 

 cline. * * * The Snake River has a deep and narrow valley cut into soft gray argillaceous 

 sandstones, which lie horizontally or dip at a low angle to the east. The sandstone is massive, 

 but the beds are separated from each other by thin seams of a harder red-weathering sandstone, 

 which contains many fossils of ammonites. * * * South of Snake River is a range of hills 

 whose highest points are 2,000 feet above the river. This range is built up of hard giay sand- 

 stone, very similar to the sandstone of the Snake River vallev, only a little more indurated and 

 approaching a quartzite. 



The fossils collected in the sandstone of Snake River have been referred by 

 Whiteaves to the Cretaceous period. The list of forms is: Panopoea or Pleuromya?, 

 Thracia, Tellina?, Inoceramus, Desmoceras? possibly D. qffine cf. D. liardense W. 



Q-R 8-10. MACKENZIE BASIN. 



Dawson ^""^ refers to Richardson's observations on the lower Mackenzie and 

 along the Arctic coast eastward, in accordance with which Cretaceous rocks are 

 indicated in this region. McConnell ^^"^ made a reconnaissance of the Mackenzie 

 and Porcupine basins, and regarding the area here in question says : 



The plains bordering the lower part of the Liard and the upper part of the ^Mackenzie rest 

 on Devonian limestones and shales, and the Cretaceous rocks were not detected in descending 

 the latter stream until the Dahadinni River, in latitude 64° north, was reached. They consist 

 here of a couple of hundred feet of dark-gray shales and sandstones. They are exposed along 

 the valley for 10 or 12 miles, and are then concealed by the bowlder clay, but probably 

 continue under the latter as far as the Tertiary basin at the mouth of Bear River, a distance 

 of 50 miles. The Cretaceous beds here occupy a depression between two high ranges of lime- 

 stone mountains and can not have a greater width than lO.or 15 miles. They have been separated 

 from the Cretaceous beds which form the western shores of Great Bear Lake by the elevation 

 of the Mount Clark range. 



Forty miles below Bear River the Cretaceous beds reappear on the banks of the Mackenzie, 

 and with the exception of one break of a couple of miles where they have been removed by 



