Middle Wisconsin bear and rodent remains discovered on Prince of Wales Island, Alaska [Restes d’ours et de rongeurs du Wisconsin moyen découverts sur l’île Prince of Wales, Alaska].

Résumé

A vertebrate microfauna of even older age has been found in Devil's Canopy Cave, located 35 km southeast of On Your Knees Cave in a narrow neck of land between El Capitan Passage and Whale Passage. This cave contains a stream and is part of an extensive hydrologic cavern complex. Rodent remains have been recovered from a 1 m thick silt deposit located in a dry passage 5 m above the present stream level. In 1992 a marmot (Marmota) incisor was found which is beyond the age of radiocarbon dating, or >44,500 yr B.P. (AA-8871A). Marmots do not currently live on Prince of Wales Island and have not been found in post-glacial deposits. In 1994, 100 kg of slumping silt were wet screened in the cave and searched for bone. Recovered elements include a marmot molar, a lower jaw of deer mouse (Peromyscus), a number of skeletal elements of small rodents, and some insect and plant fragments. The marmot molar is smaller than the hoary marmot (M. caligata) that lives on the Alaska mainland but is similar in size to the yellow-bellied marmot (M. flaviventris) of the western United States. Further investigation may reveal fossiliferous units within the undisturbed portion of the deposit.