EARLIER TERTIARY (EOCENE AND OLIGOCENE). 793 



The Colville series has been but little disturbed. The beds he nearly horizontal. * * * 



Observations naade along Colville River indicate that the series has a thickness of 500 or 

 600 feet. 



On account of difference in degree of consohdation of the beds, together with their fossil and 

 lignite contents, the series has been separated by the writer into two parts, upper Colville and 

 lower ColvUle. It is possible that an unconformity may exist between the lower and upper parts 

 of the series, but if present it must be very sHght. 



The lower Colville (Oligocene) constitutes the main portion or lower three-foilrths of the 

 section exposed at the mouth of the Anaktuvuk. It is about 150 feet thick, while the upper 

 Colville at this same locality is about 40 to 50 feet thick. The lower Colville contains the more 

 indurated class of rocks and consists mainly of partially consolidated silts in beds 6 to 8 feet in 

 thickness. They are usually hght slate-colored or ash-colored, constitute about one-haJf of the 

 lower Colville section, and are generally much less consolidated toward the top than near the 

 base. The harder rocks, which increase in volume toward the base of the section, include 

 impure duU-gray medium to fine grained sandstone with detrital hgnitic plant remains; slate- 

 colored and brownish calcareous shale, with disseminated undeterminable vegetable detritus; 

 lignitic coal in layers 1 to 5 feet in thickness; dark slate-colored or brownish chert, containing 

 cavities incrusted with chalcedonic silica; rusty brown, very ferruginous sandstone or impure 

 ironstone, and some iron-stained sihceous conglomerate, which also contains hgnitic vegetable 

 remains. There are also a few layers of hardened silts, forming a rock of very fine texture, 

 resembling soft, smooth hone stone. 



The lower Colville is tentatively classed as Oligocene, on account of the presence in it of 

 lignite beds and vegetable remains, and from its resemblance to the Kenai beds occurring else- 

 where in Alaska, and also on the ground of its relation to the supposed Phocene silts which it 

 immediately underlies. 



The Kenai is now generally referred to the Eocene. For Schrader's description 

 of the upper Colville (Pliocene) see Chapter XVII (p. 838). 



R 26-27. NORTHEAST COAST OF GREENLAND. 



Nathorst,^"^ in a report on the geology of northeastern Greenland states : 



The Tertiary is found in two different facies. On Hochstetters Vorland they occupy a 

 large territory and are composed of fine-grained yellowish sandstone with impressions of marine 

 shells. These are found, according to Copeland, in great quantities, but the collections that 

 were here brought together had to be left behind to a great extent on Kuhn Island. The 

 specimens that were brought home were some unidentifiable casts of Cytherea, Veniis, and 

 Lucina, to which Th. Fuchs later added Astarte and Pecten, after he had again been over the 

 collections. This locahty deserves to be explored again,. but unfortunately the ice rarely breaks 

 up and, remaining solid for years, makes the shore seldom accessible from a vessel. 



The rest of the Tertiary is found in connection with the basalts and is covered by them. 

 Whether it is also underlain by them is not made clear from the text, but judging from the map 

 it would seem to be the case. They sometimes contain layers of coal, and on Sabine Island are 

 found fossil plants, namely Taxodium distichum miocenum Hr., Populus arctica Hr., Diospyros 

 Irachysepala Al. Br., and Celastrus sp., described by Heer. These specimens indicate the flora 

 to be contemporaneous with the common Arctic Tertiary flora that Heer considers to be of 

 Miocene age [upper Eocene (?), Knowlton]. 



