Rock Densities:

Phanerozoic section in the vicinity of Lead-Deadwood:

Kleinkopf and Redden (1975) used a value of 2.43 g/cm³ for topographic gravity corrections in the northern portion of the Black Hills.

Precambrian in the Homestake Mine, Lead, SD

An extensive gravity survey in the Homestake underground, between the 800 and 6950 levels, yielded a mine average value of density of 2.82 g/cm³.   ( R.D. Nutsch, 1989, Subsurface gravity in the Homestake Mine, Lead, South Dakota, M.S. Thesis, University of Idaho, 155 p.)