Pennsylvania, USA

One of the original 13 states of the USA. A state with diverse geology ranging from Precambrian regions in the easternmost areas, vast beds of dolomitic limestones, Pennsylvanian period formations containing both anthracite coal (eastern) and bituminous coal (western). Triassic diabase intrudes older rocks along the eastern border and into the center of the state.

References:
- Genth, F.A. (1875) Preliminary Report on the Mineralogy of Pennsylvania. Second Geological Survey of Pennsylvania, Harrisburg.
- Gordon, S.G. (1922) The Mineralogy of Pennsylvania. 255 pp., Philadelphia.
- D. M. Lapham, J. H. Barns, W. Downey Jr. and R. B. Finkelman (1980): Mineralogy associated with burning Anthracite deposits of Eastern Pennsylvania. Commonwealth of Pennsylvania, Department of Environmental Resources, Bureau of Topographic and Geologic Survey, Mineral Resources Report 78, 82 pp.