838 INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



The Bear River Tertiary basin, measured along the Mackenzie, has a length of about 40 

 nules. Its width was not ascertained, but Tertiary beds probably underlie the flat country 

 which borders Bear River for 20 mUes above its ntiouth. They can not extend more than 15 or 

 20 miles in a westerly direction, as a lofty limestone range runs parallel with the river at about 

 that distance. The distribution of the beds is thus limited to an area 40 or 50 nules in length 

 and 30 or 40 in width and may be considerably less. 



The beds of this Tertiary basin are evidently lacustral in their origin and both in litho- 

 logical character and stratigraphical position have a much closer resemblance to the Miocene 

 (White River) of the Cypress Hills and neighboring areas than to the Laramie, with which their 

 fossil flora correlates them. Like the Cypress HUls beds, they are characterized by their irregu- 

 lar deposition, by their slight induration, and by the large proportion of gravel and pebble beds 

 which they contain, and a further degree of relationship is evidenced by the fact that they both 

 rest unconformably on the beds beneath. 



Knowlton, in a personal communication, states that the "Bear River Ter- 

 tiary" of the Mackenzie Valley is the equivalent of the Fort Union of the United 

 States and is lower Eocene. 



R 5-6. ARCTIC COASTAL PLAIN, ALASKA. 



In traversing the Colville Valley Schrader^"*'' distinguished Oligocene and 

 Pliocene strata of the region as the Colville series. For his description of the lower 

 Colville (Oligocene) see Chapter XVI (pp. 792-793). In regard to the upper Colville 

 (Pliocene) he states: 



This portion of the section is practically free from indurated rock. It consists of nearly 

 horizontally stratified beds of fine gray, slate-colored, or ash-colored calcareous sUts, containing 

 faunal remains. It is tentatively assigned to the Pliocene on the basis of fossils collected in 

 place by the writer in the bluff (near its top) on the west side of the ColviUe about a mile north 

 of the seventieth parallel. These have been reported on by Dr. Dall. [List follows.] 



R-TT 16-22. ARCTIC ARCHIPELAGO AND WESTERN GREENLAND. 



Dawson ^"^ in 1886 wrote of the "Arctic Miocene:" 



The so-called Miocene of Greenland and Grinnell Land is now regarded as equivalent to 

 the Laramie, or at least not newer than Eocene, by Mr. J. Starkie Gardiner, Sir William Daw- 

 son, and other paleobotanists. Our knowledge of the flora of the Banks Land beds is very 

 slight, being confined to that of the structure of a few specimens of fossil woods * * * ^Ijich 

 have been reported on by Dr. C. Cramer, but, so far as it goes, it presents no features incom- 

 patible with the possible Laramie age of these deposits also. 



The Tertiary plant-bearing sediments on the west cbast of Greenland are 

 described by White and Schuchert^"^" as conformable to the Cretaceous Patoot 

 series. 



The Patoot series, which appears lithologically and stratigraphically to be inseparable 

 from the Atane series, contains at the same time many plants common in the upper part of 

 the Amboy clays, with others allied more closely to the higher Cretaceous floras, such as that 

 of the Laramie. The Patoot series may perhaps be safely interpreted as constituting a paleonto- 

 logical as well as sedimentary transition from the Atane series to the Tertiary. The thickness 

 of the Atane and Patoot series (Senonian) is not less than 1,300 feet and may considerably 

 exceed this. 



