These areas have rugged topography with many long and broad U-shaped glaciated valleys, many of which terminate at tidewater. Side slopes are very steep and exposed bedrock is common along the glacially scoured valley walls. The rolling moraine landforms dominate the low hills and valley bottoms. Lithology and Stratigraphy. The geology is very complex, consisting of the Craig and Admiralty subterranes, and the Wrangellia, Chugach, and Taku terranes, all of which are volcanic islands-arcs and continental fragments.
Most rock types are Jurassic to Mesozoic deposits of sedimentary and volcanic rock types.
Many of the assemblages have been metamorphosed, faulted, or folded, and the trending of most faults is northwesterly. Predominant soils are Terric Cryohemists, Humic Cryorthods, Humic Lithic Cryorthods, and Andic Humicryods. Most of the soils on the steep slopes are formed in colluvial or landslide materials. Poorly drained depressions or low-lying areas are peatlands. Potential Natural Vegetation.