No type locality designated. Named after Towner Lake, T16N, R79W, Albany Co, WY in the Northern Rocky Mountain region. Consists of massive to schistose chloritic and hornblendic rocks. The massive phase is fine grained and ophitic. General characteristics suggest it was a series of basic pyroclastics and flows. Best exposures found between Brooklyn Lodge and Towner Lake. Varies from 600 to more than 1,200 ft in thickness. Is younger than Ranger marble and older than French slate. Is of pre-Cambrian, early Algonkian or Proterozoic age.

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

Revised in that Towner Greenstone assigned as the middle formation of the upper part of the Libby Creek Group of the Snowy Pass Supergroup (first used) in the Medicine Bow Mountains of south-central WY in the Northern Rocky Mountain region. Is structurally conformable with the underlying Nash Fork Formation, basal formation of the upper part of the Libby Creek. Is conformable with the overlying French Slate, upper formation of the upper part of the Libby Creek. Consists of massive to schistose amphibolite with several lenses of coarse-grained sandstone and fine-grained metachert. The greenstones are primarily actinolite with variable amounts of chlorite, albite, epidote, carbonates, opaque minerals, and sphene. May be a marine deposit or of intrusive origin. Geologic map; stratigraphic chart. Of Proterozoic age.

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

Assigned as one of three formations to the upper part of the Libby Creek Group of the newly defined Snowy Pass Supergroup in the Medicine Bow Mountains, WY in the Northern Rocky Mountain region. Underlain by Nash Fork Formation and overlain by French Slate, both formations of the Libby Creek Group of the Snowy Pass Supergroup. Correlated with a part of the Slaughterhouse Formation of the upper part of the Snowy Pass Group of the Sierra Madre. Geologic map; correlation chart. Of Early Proterozoic age.

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