The Oella Formation is a Late Proterozoic or early Cambrian schist in Howard and Baltimore Counties, Maryland. It is described as "Medium-grained biotite-plagioclase-muscovite-quartz schist, locally garnetiferous, interlayered on a centimeter to decimeter scale with fine-grained biotite-plagioclase-quartz gneiss, commonly bearing muscovite but less commonly garnet."Crowley, W.P. and Reinhardt, Juergen, 1980, Geologic map of the Ellicott City quadrangle, Maryland: Maryland Geological Survey, scale 1:24,000. (online)
Type locality The type locality is along the Patapsco River at Oella, southwest Baltimore County.
See also
Ellicott City Granodiorite
References