The Baltimore Gneiss has been affected by three deformation periods: the Grenvillian, known from radiometric age data, for which nearly all resulting structural features where destroyed or obstructed by later tectonic deformation; the Taconic-Acadian, which involved three phases of folding, amphibolite facies metamorphism, local migmatization, and the development of the gneiss's pervasive structural elements; and the Alleghanian-Palisades, which resulted in predominantly brittle faulting and open folding.

[6] The type locality of the Baltimore Gneiss as described by William Patrick Crowley of the Maryland Geological Survey in 1976 is defined as outcrops along Towson Run from Bellona Avenue to Towsontown Boulevard.

[2] The type locality of the layered gneiss member includes stream cuts along Herring Run for 255 meters on either side of Arlington Avenue bridge near Morgan State University.

[2] The type locality of the augen gneiss member includes outcrops along Long Green Creek 385 meters southeast of Glenarm Road bridge.

[2] The type locality of the streaked-augen gneiss member includes outcrops along Merryman Branch 125 meters upstream from the Dulaney Valley Road bridge.

[2] Some notable exposures of the Baltimore Gneiss in addition to the type localities mentioned above include outcrops along the Rapids Trail in the McKeldin Area of Patapsco Valley State Park and along roads around the Loch Raven Reservoir.