Greensburg Quarry (McMahon Quarry), Valley Stream, Baltimore Co., Maryland, USA
Ref: Minerals of the Washington D.C Area.
Operated for crushed stone by Arundel Corporation of Baltimore.
In gneissic facies Cockeysville marble (calc-gneiss, scattered layers and lenses of calcite marble). Pegmatite and small quartz veins are common and a fine-grained mafic dyke (high proportions of ferro-magnesian minerals; mostly amphiboles).
Mineral List
22 entries listed. 16 valid minerals.
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