8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 28 



intrusions, indicating an igneous core.) Shale and limestone pre- 

 dominate, (2) The mountain slopes verge into an undulating plain 

 which includes most of the drainage basin of the Colville River 

 (25,000 square miles). This second region is sharply set off from 

 (3) the great wet tundra plains by an old beach escarpment which 

 is 50 to 300 feet above the lake and pond area to the north — some 

 25,000 square miles that is more water than land. At the foot of this 

 escarpment the elevation is about 400 feet above sea level. This gives 

 a fall of 400 feet in about 100 miles to the coast at Barrow. The 



Fig. 2. — Map of northern Alaska, i, Kukpoivruk River. 2, Kokolek River. 

 3, Utokok River. 4, Kuk River. 5, Meade River. 6, Topagoruk River. 7, 

 Ikpikpuk River. 8, Elson Lagoon. 9, Admiralty Bay and Dease Inlet. 10, Smith 

 Bay. II, Teshekpuk Lake. 



drainage surface thaws to a depth of 12 to 18 inches during summer, 

 which is the only time of year when any movement of water occurs 

 over the tundra. Throughout this plain the ground is frozen to a 

 depth of nearly 1,000 feet (permafrost). All but the largest rivers 

 freeze solidly in winter. Lakes are very numerous and in general are 

 oriented north and south. 



Many rivers in this third region flow northward to the Arctic 

 Ocean (fig. 2) ; three large ones, the Meade, Topagoruk, and Chip, 

 empty into Admiralty Bay, which in turn becomes Dease Inlet and 

 Elson Lagoon. To the southwest is the Kuk River, which enters the 

 ocean at Wainwright. Beyond Icy Cape are the mouths of three 

 rivers, the Utokok, Kokolek, and Kukpoivruk. To the east of Elson 



