Lower Colville River, Locality 86/38
|Northern Alaska Map|
Kogosukruk Tongue of the Prince Creek Formation. At the base of the exposed section is a light gray/ olive sandy mudstone at least 60 cm thick that is heavily rooted. This is overlain by a darker 'sooty' horizon (2.5 cm thick) with plant fragments. Above this is a dark gray mudstone approximately 5 cm thick underlying a 25 cm thick coal with plant fragments and large bituminised logs. Above the coal is a gradational contact with a 5 cm thick gray claystone and a 15 cm thick bentonitic layer. This is overlain by a brown sandy seat earth (10 cm thick) underlying a bituminous coal (24 cm thick), which is in turn overlain by a brown coarsening upward claystone (22 cm thick) passing into a 15 cm thick bituminous coal. Above this is a dark gray claystone (25 cm thick) with abundant carbonised wood fragments, followed by a 2.5 cm thick claystone and then a 10 cm thick mudstone with a high concentration of coaly compressed logs, reminscent of a washed in log jam.
The pattern of deposition outlined above continues upsection with further concentrations of log and branch wood in mudstones, paper coals, and bituminous coals. The units are traceable laterally over considerable distances.
|Interactive map of the lower reaches of the Colville River showing plant fossil localities sampled by Smiley (1969) and by Parrish and Spicer in 1986.|
|Part of the exposure of the Prince Creek Formation (formerly the Kogosukruk Tongue of the Prince Creek Formation) on the western side of the Colville River between Uluksrak Bluff and Ocean Point.|