Oronto Group; Nonesuch Shale (MIYn;0)

State	Michigan
Name	Oronto Group; Nonesuch Shale
Geologic age	Middle Proterozoic
Original map label	Yn
Primary rock type	siltstone
Secondary rock type	shale
Other rock types	sandstone
Lithologic constituents	Major Sedimentary > Clastic > Sandstone (Bed)Gray, green, and brown lithic siltstone, shale, and sandstone. Copper sulfides and native copper occur locally near base Sedimentary > Clastic > Mudstone > Shale (Bed)Gray, green, and brown lithic siltstone, shale, and sandstone. Copper sulfides and native copper occur locally near base Sedimentary > Clastic > Siltstone (Bed)Gray, green, and brown lithic siltstone, shale, and sandstone. Copper sulfides and native copper occur locally near base
Map references	Sims, P.K., 1992, Geologic map of Precambrian rocks, southern Lake Superior region, Wisconsin and northern Michigan: U.S. Geological Survey Miscellaneous Investigations Map I-2185, scale= 1:500,000 [http://pubs.er.usgs.gov/publication/i2185]
Unit references	Sims, P.K., 1992, Geologic map of Precambrian rocks, southern Lake Superior region, Wisconsin and northern Michigan: U.S. Geological Survey Miscellaneous Investigations Map I-2185, scale= 1:500,000 [http://pubs.er.usgs.gov/publication/i2185]
Geographic coverage	Gogebic - Houghton - Keweenaw - Ontonagon