Basalt flows and intrusive igneous rocks

Yellowstone area--Includes Osprey, Madison River, Swan Lake Flat, and Falls River Basalts, basalts of Mariposa Lake, Undine Falls Basalt, and gravels, sands, silts, and basalts of The Narrows. In and adjacent to Absaroka and Washakie Ranges--Includes basalt of Lava Mountain (age about 0.5 Ma).
State Wyoming
Name Basalt flows and intrusive igneous rocks
Geologic age Pleistocene
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Igneous > Plutonicintrusive igneous rocks
Incidental
Unconsolidated > Coarse-detrital > Gravel (Alluvial)
Unconsolidated > Fine-detrital > Silt (Alluvial)
Unconsolidated > Coarse-detrital > Sand (Alluvial)
References
NGMDB product
Counties Fremont - Park - Teton