Cockeysville Marble

The Cockeysville Marble is a Precambrian, Cambrian, or Ordovician marble formation in Baltimore, Carroll, Harford and Howard Counties, Maryland. It is described as a predominantly metadolomite, calc-schist, and calcite marble, with calc-gneiss and calc-silicate marble being widespread but minor.[1]

Sample of Massive Metadolostone Member of Cockeysville Marble, from old quarry near Lower Dam of Loch Raven Reservoir, Baltimore County, Maryland

Cockeysville Marble Stratigraphic range: Precambrian, Cambrian, or Ordovician
Polished slab of the marble from Cockeysville. Width of slab inside black border is approximately 10.7 cm.
Type	metamorphic
Unit of	Glenarm Supergroup
Underlies	Wissahickon Formation
Overlies	Setters Formation
Thickness	about 750 feet[1]
Lithology
Primary	marble
Location
Region	Piedmont of Maryland
Type section
Named for	Cockeysville, Maryland
Named by	Williams and Darton, 1892[2]

The extent of this formation was originally mapped in 1892[2] within Baltimore County.

Quarrying

The Beaver Dam Quarry in Cockeysville, c. 1898

The Cockeysville Marble has been quarried in Beaver Dam within Cockeysville and other locations in Maryland. A historical account is given in Maryland Geological Survey Volume Two.[3]

The Cockeysville was also mined for crushed stone at what is now called Quarry Lake.[4] It was known as the McMahon Quarry in the 1940s.

The Washington Monument in Baltimore and the one in Washington, D.C. are constructed from the Cockeysville Marble.

See also

• List of types of marble

References

1. Geologic Map of Maryland, 1968. Cleaves, E. T., Edwards, J. Jr., and Glaser, J. D. Maryland Geological Survey. Scale 1:250,000.
2. Williams, G.H., and Darton, N.H., 1892, Geologic map of Baltimore and vicinity: U.S. Geological Survey, Map to accompany "Guide to Baltimore".
3. Maryland Geological Survey Volume Two, by W. B. Clark, 1898. Johns Hopkins University Press. (Google Books)
4. McMahon Quarry (Greensberg Quarry), Bare Hills, Baltimore Co., Maryland, USA