COLVILLE OR ARCTIC SLOPE PROVINCE 237 



tance of 160 miles. It consists primarily of two distinct features, a very 

 gently rolling plains country, for which is proposed the name Anaktoovuk 

 plateau, and a nearly flat tundra country or coastal plain. The inland 

 edge of the Anaktoovuk plateau, which is composed of Cretaceous rocks, 

 has an elevation of 2,500 feet, and with gentle slope extends northward 

 for a distance of 80 miles to latitude 69° 25', where, at an elevation of 

 800 feet, it is succeded by the nearly flat Tertiary coastal plain, which, 

 with very gentle slope, extends 80 miles farther northward to the Arctic 

 coast. The drainage of this province is almost directly northward into 

 the Arctic ocean. The master stream is the Colville, whose headwaters, 

 so far as known, seem to make a somewhat wide detour to the westward 

 before flowing directly to the sea. The next larger stream is the Anak- 

 toovuk, which, rising in the mountains just east of the head of John 

 river, flows northward through the southern part of the province and 

 into the Colville. The most prominent features of the plateau are a few 

 low, transverse ridges, extending across it from east to west, feebly imitat- 

 ing the front of the mountain range and the shallow valleys that carry 

 off the drainage. 



The coastal plain, which is underlain by Tertiary beds, has a breadth 

 of about 80 miles. It descends with very gentle slope from an elevation 

 of 800 feet in the interior to near sealevel at the coast. In its inland 

 portion, the Colville river has sunk its bed to a depth of 200 feet below 

 the surface of the plain, but the interstream areas are flat, with the sur- 

 face, which appears to be fresh-constructional in form, dotted here and 

 there by extremely shallow ponds and lakelets, which in most instances 

 are without outlet and present no suggestion of progress toward the de- 

 velopment of any system of drainage. 



Geological Section 



The horizontal scale of the section (plate 40) is 10 miles per inch. In 

 order to show the structure in the Tertiary coastal plain and represent the 

 flats and delta near sealevel at the north, it has been given a vertical ex- 

 aggeration of 5 : 1. As the section is confined to the line of traverse, in 

 order to represent more accurately the relations of the rocks as actually 

 observed, it deviates somewhat from a straight line in its extent across 

 the field from A to J. Owing to this restriction to the line of traverse 

 in the valleys where the relief has been relatively reduced by erosion, 

 especially in the mountainous portions, the profile rarely rises to the 

 normal, height of the top of the Endicott plateau ; consequently this 

 plateau feature of the range is not represented by the profile of the sec- 

 tion. At the northern base of the mountains, where the profile descend- 

 ing from the mountains, passes from the upturned Devonian on to Plies- 



