flows NE to Little Nelchina River, N of Limestone Hills and 18 mi. NW of Tahneta Pass, Talkeetna Mts.
Named about 1952 by U.S. Geological Survey (USGS) geologists "after a fossil."
Horn Mountain, Syncline Mountain,
Mountain Passes:Horsepasture Pass, Limestone Gap,
Mountain Ranges:Streams:Alfred Creek, Ammonite Creek, Bench Creek, Billy Creek, Cadoceras Creek, Cardiceras Creek, Cardioceras Creek, Chitna Creek, Conglomerate Creek, Divide Creek, Flume Creek, Granite Creek, Greta Creek, Horsepasture Creek, McDougall Creek, Mouse Creek, Papoose Creek, Sawmill Creek, Sawmill Creek, Sheep Creek, Sladen Creek, Whistler Creek, Wood Creek,
Valleys: