Valleys are narrow and flat-bottomed.
Lithology and Stratigraphy. The Section consists of Upper Cretaceous rocks with minor fragments of Koyukuk and Tozitna terranes. The dominant soils are Aquepts that have a pergelic temperature regime. Cryaquepts occur on areas of impeded drainage underlain by permafrost. Cryumbrepts and Cryorthents are principal soils on high ridges and where surfaces drain well.