Named for Overland Creek near town of Arlington, Carbon Co, WY. Type area designated as outcrops near the junction of Overland and Rock Creeks, T19N, R79W in the northeast Medicine Bow Mountains. Crops out over 4 sq km area within the Northern Rocky Mountain region. Not in contact with the Archean quartzo-feldspathic gneiss; relationship to the gneiss is uncertain. Most of the contacts with the younger Phantom Lake Metamorphic Suite are faults or invaded by gabbro sills. Considered older than the Phantom Lake. Stratigraphic table. Petrographic data. Geologic map. Consists of a succession about 1,200 m thick of hornblende and biotite gneisses. Hornblende gneisses compose 80 percent of formation; biotite gneisses are dominated by plagioclase, quartz, biotite, and muscovite. Interpreted to be of volcanic origin because of its mafic composition and because a few outcrops of amphibolite have structures that resemble amygdules. May be the remnant of an Archean greenstone belt. Is older than Stud Creek Metavolcaniclastics (named) of Phantom Lake Metamorphic Suite. Correlated with Vulcan Mountain Metavolcanics (new) in the Sierra Madre Mountains. Was intruded by the 2,430 Ma Baggot Rocks Granite indicating a Late Archean age.

Source: GNU records (USGS DDS-6; Denver GNULEX).