698 INDEX TO THE STRATIGEAPHY OF NORTH AMERICA. 



Bell River, and the remainder are from ironstone nodules from the west bank of the Assiniboine 

 Valley at Millwood, a short distance south of the present map. 



The total thickness of the Pierre in northwestern Manitoba is 800 feet or more. The 

 Millwood series, as seen in the valleys on the northern face of riding Mountain, has a thickness of 

 between 450 and 500 feet, while about 300 feet of the overljing Odanah series is there also 

 seen, reaching to near the summit of the mountaiins and being immediately overlain by the 

 drift deposits. The top of the Odanah series is not seen. 



O 4^5. ALASKA PENINSULA. 



Atwood *^^ in a report on the mineral resources of southwestern Alaska dis- 

 cusses the Jurassic and Cretaceous of the peninsula, stating in regard to the Upper 

 Cretaceous : 



Upper Cretaceous sediments are exposed in the mountains northwest of Chignik Bay and 

 west of Chignik Lake. They are also present in the Herendeen Bay district. They * * * 

 consist of sandstones, shales, conglomerates, a little limestone, seams of bituminous coal, and 

 some lignite. Upper Cretaceous fossils were procured by Paige '^ from the coal measures in the 

 Herendeen Bay field and by the present writer from the several other localities above mentioned 

 in this district and in the region of Chignik Bay. 



(See also Chapter XIII, p. 574.) 



O 8. SOUTHEASTERN ALASKA. 



See Chapter XIV (pp. 632-633). 



O 10-12. NORTHERN BRITISH COLUMBIA AND ALBERTA. 



The northern portion of the great Cretaceous area of the plains has been exam- 

 ined 0^ Liard, Peace, and Athabaska rivers and their tributaries. McConneU ^^'"' 

 describes the structural relations in the eastern foothills and out on the plains and 

 concludes: 



The Cretaceous section along the Liard shows two great shale and sandstone series separated 

 by a heavy band of sandstones and conglomerates. The lower shales, from the imperfect fossil 

 evidence at hand and also from their lithologic character, may be referred tentatively to the 

 horizon of the Queen Charlotte Islands, or Kootanie formation, the upper shales to that of the 

 Benton, while the intervening conglomeratic band probably represents the Dakota. The litho- 

 logical succession of the Cretaceous beds here is almost identical with that which obtains in 

 other parts of the CordUleran belt north of the internationalr boundary and on the Queen Char- 

 lotte Islands and shows that similar conditions of deposition prevailed at the same time over 

 this whole area. 



The Cretaceous roclis cross the Liard with a width of over a hundred miles and north of 

 the river enter a bay in the mountains, the extent of which to the northwestward is not known; 

 southward they are connected with the great Cretaceous basin in the plains. 



South of the liard the next section examined is that of Peace River, which 

 was seen by Selwyn^^' and McConnell.^^^ Dawson ^^^* observed the Cretaceous 

 rocks more fully in a parallel section on Pine River, a tributary of the Peace near 

 longitude 121° and utihzed Selwyn's notes in the following discussion: 



Cretaceous beds in the vicinity of the [Rocky] Mountains appear to be composed almost 

 exclusively of sandstones and conglomerates and with little exception maintain this character 



a Paige, Sidney, The Herendeen Bay coal field: Bull. U. S. Geol. Survey No. 284, 1906, p. 103. 



