476 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1950 



The Foothills Province (pi. 2), characterized by low hills and 

 ridges, is divided into two sections. The more elevated southern 

 foothills border the mountains with elevations up to 3,000 or 3,500 

 feet, while the more subdued northern foothills section averages 

 from about 400 to 600 feet in height. These foothills, made up mainly 

 of Mesozoic rocks, are less deformed and less resistant than the 

 mountains. There are many crustal warpings — called anticlines and 

 synclines — in this province, which have their axes parallel, east and 

 west. These warpings produce ridges that give the country a linear 

 aspect when viewed from the air, much like the AUeghenies in 

 Pennsylvania. The folding is intense near the mountains, and the 

 beds of rock stand nearly vertical in places. Farther away from 

 the mountains to the north, where the folding is more gentle and 

 the beds lie nearly horizontal, the hard layers form steps on the hill- 

 sides or cap the hills. The j)rominent ridges of the western foothills 

 extend almost continuously for about 225 miles across the western 

 front of the Brooks Range. Except where glacial tongues may have 

 found their way into some of the valleys adjacent to the mountains, 

 this province has not been glaciated. 



The third and northernmost province, the Arctic Coastal Plain 

 Province — also never glaciated — is a low-lying prairie-type area that 

 was once submerged under the sea during late geologic times of the 

 Quaternary period and later uplifted. No thick deposits of marine 

 material were laid down (Smith and Mertie, 1930, p. 238). The 

 monotonous flatness of this province, extending to about 70 miles in- 

 land from the coast, is relieved by a few isolated knobs and hills. 

 These hills are generally about 50 to 100 feet in height, and a few 

 reach 300 feet. The deposits of the coastal plain are composed of un- 

 consolidated sands, gravels, and clays. They are dominantly alluvial 

 stream deposits and probably include some glacial and interglacial 

 deposition. There are deposits of Pleistocene sands near the coast, 

 called Gubik sands, which are rich in fossil life. They are of wind- 

 blown origin, or loess. It is conceivable that there may be found some 

 evidence of Ancient Man in the upper layers of these sands. This 

 coastal region, owing to its flatness, naturally has the poorest drain- 

 age of the three provinces. It is characterized by its wetness, many 

 pools of standing water, lakes, and sluggish and meandering streams. 

 The general wetness is due to both poor surface drainage and the 

 permafrost, or permanently frozen ground, which extends from a few 

 feet below the surface to a depth of almost 1,000 feet in some places. 

 A phenomenon called frost- wedge (pi. 1), a wedge-shaped mass of 

 subsurface ice, is common in the Arctic. 



The climate of the north slope is arid, with a precipitation of only 

 5 to 7 inches. Although there is little rain or snow, the air is 

 frequently filled with a misty haze in summer. The only explanation 



