In the Talkeetna Mountains on the E side of the Oshetna River valley; extends N-S 3 mi. E of the junction of little Ophetna and Oshetna Rivers, 15 mi. S of Susitna River, 67 mi W of Gulkana, Talkeetna Mts. 6 miles long.
Named in 1956 by U.S. Geological Survey (USGS) for the large fossil mammoth or mastodon bones found on its top.
Black River, Little Oshetna River,
Streams:Conglomerate Creek, Ferrell Creek, Fourth of July Creek, Joe Creek, Nicolie Creek, Red Creek, Sellick Creek, Tolson Creek, Walker Creek, White Sand Creek, Yacko Creek,