Abdypoor, G., and Bischke, R.E., 1982. Earthquakes felt in the state of Pennsylvania: with emphasis on earthquakes felt in Philadelphia, Pennsylvania and surrounding areas, Pennsylvania. Temple University Dept. of Geology.

Armbruster, J.G., and Seeber, L., 1987. The 23 April 1984 Martic earthquake and the Lancaster seismic zone in eastern Pennsylvania. Bull. of the Seismological Society of America, vol. 77, no. 3, pp. 807-890.

Armbruster, J.G., and Scharnberger, C K., 1986. Lancaster earthquakes. Jour. of the Lancaster Co. Historical Society, v. 90, no. 2, p. 78-86.

Armbruster, J.G., Baron, H., Bodin, P., and others, 1998. Preliminary results from the investigation of the Pymatuning earthquake of September 25, 1998. Pa. Geology, vol. 29, no. 4, pp. 2-14.

Gordon, D.W., and Dewey, J.W., 1989. Earthquakes in The Geology of Pennsylvania, Charles Shultz, editor. Harrisburg, Pa. pp. 763-769.

Howel, B.F., Jr. 1979. Earthquake expectancy in Pennsylvania. Pa. Academy of Science Proceedings, vol. 53, pp. 205-208.

Nottis, G.N., editor, 1983. Epicenters of northeastern United States and southeastern Canada, onshore and offshore: time period 1534-1980. New York State Museum Map and Chart Series 38.
 

Scharnberger, C K., 1984. Lancaster's Easter earthquake. Pennsylvania Geology, v. 15, no. 3 p. 2-5.

Scharnberger, C.K., 1988. Pennsylvania seismicity reexamined (abstract). Seismological Research Letters, vol. 59, p. 14.

Scharnberger, C.K., 1989. Earthquake Hazard in Pennsylvania. Pa. Geol. Survey, 4th ser., Educational Series 10.

Scharnberger, C.K., and Howell, B. F., Jr. 1985. Intensities and structural setting of the earthquake of 19 April and 23 April, 1984, Lancaster County, Pennsylvania. Earthquake Notes, vol. 56, p. 43-46.

Scharnberger, C.K., and Thompson, G., 1983. Chickies Rock in Geology along the Susquehanna River, south-central Pennsylvania. Harrisburg Geologic Society Field Trip Excursion Guide, J. Ronald Mowery, editor.

Scharnberger, C.K., Jones, J.L., and Kreiger, W., 1999. An Earthquake in York County, Pennsylvania. Pennsylvania Geology, vol. 30, no. 1/2, pp. 10 - 13.

Doyle, K. D. and H. D. Sues, 1995.  Phytosaurs from the Upper Triassic New Oxford Formation of York County, Pennsylvania.  Jour. Vertebrate Paleontology, vol. 15,  p.545-553. 

Guilday, J. E., Hamilton, H. W., and McGrady, A. D., 1966. The bone breccia of Bootlegger Sink, York County, Pennsylvania. Annals of Carnegie Museum, v. 38, art. 8, p. 145-163.

Hickok, W. O. and Bradford, W., 1933. Dinosaur footprint tracks near Yocumtown, York County, Pennsylvania. Pa Acad. Science Proceedings, v. 7, pp. 55-58.

Kochanov, W. E., and R. M. Sulivan, 1994.  Finding phytosaurs in Pennsylvania: the story of Stahle, Sinclair and Zions View.  Pennsylvania Geology, Vol. 25, p. 3-8.

Lucas, Spencer G., and Sullivan, Robert, 1996. Fossils provide a Pennsylvania standard for part of the Late Triassic time. Pennsylvania Geology, vol. 27, no. 4.

Sullivan, R M., and Randall, K. A., 1996. Pennsylvania's prehistoric Pachyderms. Natural History Notes of the State Museum of Pennsylvania. Number 2, November.

Taylor, J. F., and Durika, N. J., 1990. Lithofacies, trilobite faunas, and correlation of the Kinzers, Ledger and Conestoga Formations in the Conestoga Valley in 55th annual Field Conference of Pennsylvania Geologists, Carbonates, schists and geomorphology in the vicinity of the lower reaches of the Susquehanna River, Charles Scharnberger, editor. Harrisburg, PA.

Wanner, H. E., 1921. Some faunal remains from the Trias of York County, Pennsylvania. Proceedings of the Academy of Sciences, Phila., v. 73, p. 23-37.

Wanner, H. E., 1926. Some additional faunal remains from the Trias of York County, Pennsylvania. Proceedings of the Academy of Natural Sciences, Phila., v. 78, p. 21-28.

Wherry, E. T., 1912. Silicified wood from the Triassic of Pennsylvania. Academy of Natural Sciences Proceedings 64, Phila., p. 366-379.

Ansley, J.E., 2000.  The Teacher-Friendly Guide to the Geology of the Northeastern United States.  Paleontological Research Institution, Ithaca, NY.

Berg, T., 1984. Rock Types of Pennsylvania. Pa Geol. Survey, 4th ser., Map 63.

Berg, T., and Dodge, C., 1981.  Atlas of preliminary geologic quadrangle maps of Pennsylvania.  Pa. Geol. Survey, 4th ser., Map 61.

Berg, T. M., McInerney, M. K., Way, J.H. and MacLachland, D.B., 1983. Stratigraphic correlation chart of Pennsylvania. Pa. Geol. Survey, 4th ser., General Geol. Rept. 75.

Blackmer, G., and Brown, C. H., 2006. Bedrock geologic map of the Parkesburg Quadrangle, Chester and Lancaster Counties, Pennsylvania. Pa. Geol. Survey, 4th ser., Open-File Report OFBM-06-03.0.

Brown, C. H., 2006. Bedrock geologic map of the Honey Brook Quadrangle, Chester and Lancaster Counties, Pennsylvania. Pa. Geol. Survey, 4th ser., Open-File Report OFBM-06-02.0.

Brown, W.R., 1970. Investigation of the sedimentary record in the Piedmont and Blue Ridge of Virginia in Fischer, G.W., Pettijohn, F.J., Reed, J.C., and Weaver, K.N., editors, Studies of Appalachian Geology: Central and Southern. Interscience Press, New York.

Chrastina, P.C., and Jones, J.L., 1989. Whispering Hills, the Geology of York and Lancaster Counties, Pennsylvania. Matrix Publishing, Dillsburg, Pa.

Clark, G. M., 1991. South Mountain geomorphology in 56th Annual Field Conference of Pennsylvania Geologists Guidebook - Geology in the South Mountain Area, Pennsylvania, William Sevon and Noel Potter, Jr., editors

Clark, G. M., and Ciolkosz, E.J., 1988. Periglacial geomorphology of the Appalachian Highlands and Interior Highlands south of the glacial border. Geomorphology, vol. 1, pp. 191-220.

Geyer, A.R., 1987. Outstanding Scenic Geological Features of Pennsylvania - Part II. Pa. Geol. Survey, 4th ser., Environ. Geol. Report 7.

Geyer, A.R., and Bolles, W.H., 1979. Outstanding Scenic Geological Features of Pennsylvania. Pa. Geol. Survey, 4th ser., Environ. Geol. Report 7.

Geyer, A.R., and J. P. Wilshusen, 1982. Engineering Characteristics of the Rocks of Pennsylvania. Pa. Geol. Survey, 4th ser., Environ. Geol. Report 1.

Hall, G.M., 1973. Ground Water in Southeastern Pennsylvania. Pa. Geol.. Survey, 4th ser., Bull. W 2.

Kauffman, M. E., Eocambrian, Cambrian and transition to Ordovician in The Geology of Pennsylvania, Charles Shultz, editor. Harrisburg, Pa. pp. 548-73.

King, Albert W., 1986.  York's Stone Buildings: Geology and Architecture.  York Rock and Mineral Club Spec. Pub. 3.  York, PA

Lesley, J.P., 1892.  Summary Description of the Geology of Pennsylvania. Vol. 1.  Pa. Geol. Survey, 2nd ser.

Levin, H., 2006. The Earth through Time, 8th edition. John Wiley & Sons, Inc., New York, N.Y.

Lindsay, B.D., and Ator, S.W., 1998. Radon in Ground Water of the Lower Susquehanna and Potomac River Basins. U.S.G.S. Water Resources Invest. Report 98-1188.

Lloyd, O. B., and Growitz, D. J., 1977. Groundwater resources of central and southern York County, Pennsylvania. Pa. Geol. Survey, 4th ser., Water Res. Rept. 42.

Mowery, J. R., ed., 1983. Geology along the Susquehanna River, south-central Pennsylvania. Harrisburg Area Geol. Soc., Field Trip Guide.

Pazzaglia, F.J., and Gardner, T.W., 1994. Terraces, fluvial evolution and uplift of the Lower Susquehanna River Basin in Various Aspects of the Piedmont Geology in Lancaster and Chester Counties, Pennsylvania. 59th Annual Field Conference of Pa. Geologists, Rodger Faill and William Sevon, editors.

Rankin, D.W., Stern, T.W., McLelland, J. and others, 1983. Correlation chart of Precambrian rocks of eastern United States. U.S. Geol. Survey Professional Paper 1241-E.

Reich, J. R., 1974. Caves of southeastern Pennsylvania. Pa. Geol. Survey, 4th ser., Gen. Geol. Rept. 65.

Root, Samuel, 1977. Geology and mineral resources of the Harrisburg West area, Cumberland and York Counties, Pennsylvania. Pa. Geol. Survey, 4th ser., Atlas 148ab.

Root, Samuel, 1978. Geology and mineral resources of the Carlisle and Mechanicsburg quadrangles, Cumberland County, Pennsylvania. Pa. Geol. Survey, 4th ser., Atlas 138ab.

Rose, A.W., 1989. Other geologic environmental problems - Radon in The Geology of Pennsylvania, Charles Shultz, editor. Harrisburg, Pa. pp. 787-793.

Sevon, W. D., 1989.  Exotically sculptured diabase.  Pa. Geology, vol. 20, no. 1.

Sevon, W. D., 1990. Saprolite and landscape evolution in the Piedmont in 55th annual Field Conference of Pennsylvania Geologists, Carbonates, schists and geomorphology in the vicinity of the lower reaches of the Susquehanna River, Charles Scharnberger, editor. Harrisburg, PA.

Sevon, W. D., 1996.  Surficial geology of the Airville, Conestoga, Gap, Glen Rock, Holtwood, Kirkwood, Quarryville, Red Lion, Safe Harbor, Stewartstown, Wakefield, and York quadrangles and the Pennsylvania part of the Conowingo Dam, Delta, Fawn Grove, New Freedom, Norrisville,,, and Rising Sun quadrangles in York, Lancaster, and Chester Counties, Pennsylvania.  Pa. Geol. Survey, 4th ser., Open File Reports 96-01 to 96-18.

Shirk, William R., 1980. A guide to the geology of south central Pennsylvania. Obson & Kays, Inc, Inc. Chambersberg, PA.

Smith, II, R.C., and Barnes, J.H., 1994. Geochemistry and Geology of Metabasalt in southeastern Pennsylvania in Various Aspects of the Piedmont Geology in Lancaster and Chester Counties, Pennsylvania. 59th Annual Field Conference of Pa. Geologists, Rodger Faill and William Sevon, editors.

Socolow, A. A., 1974. Geologic interpretation of aeromagnetic maps of southeastern Pennsylvania. Pa. Geol. Survey, 4th ser., Information Cir. 77.

Stose, George W., 1953. Geology of the Carlisle Quadrangle, Pennsylvania. U.S.G.S. Geologic Quadrangle Map.

Stose, George W., and Bascom, F., 1929. Fairfield-Gettysburg folio. U.S.G.S. Geologic Atlas, Folio No. 225.

Stose, George W., and Jonas, A., 1930. Geology and mineral resources of the Lancaster 15' Quadrangle. Pa. Geol. Survey, 4th ser., Atlas 168.

Stose, George W., and Jonas, A., 1933. Geology and mineral resources of the Middletown Quadrangle, Pennsylvania. U.S. Geol. Survey Bull. 840.

Stose, George W., and Jonas, Anna I., 1939. Geology and mineral resources of York County, Pennsylvania. Pa. Geol. Survey, 4th ser., Bull. C 67.

Whitaker, J.C., 1955. Direction of current flow in some Lower Cambrian clastics in Maryland. Geol. Soc. America Bull., vol. 66, pp. 763-766.

White, W. B., 1976. Geology and biology of Pennsylvania caves. Pa. Geol. Survey, 4th ser., Gen. Geol. Rept. 66.

Wilshusen, J.P., 1979a. Environment Geology of the Greater York Area, York County, Pennsylvania. Pa. Geol. Survey, 4th ser., Environ. Geol. Report 6.

Wilshusen, J.P., 1979b. Geologic Hazards in Pennsylvania. Pa. Geol. Survey, 4th ser., Education Series 9.

Wilshusen, J.P., 1983. Geology of the Appalachian Trail in Pennsylvania. Pa. Geol. Survey, 4th ser., Gen. Geol. Report 74.

Ehrenfeld, F., 1989. A study of igneous rocks at York Haven and Stony Brook, Pennsylvania. PhD Thesis, University of Pennsylvania.

Inners, Jon D., and Wilshusen, J. Peter, 1978.  Triassic-Jurassic diabase dike at Hellam, York County, Pennsylvania.  Pa. Geology, vol. 9, no. 2.

Shellnutt, J.G., Dostal, J., and Kostak, D.J., 2003.  Magmatism of the central Atlantic Magmatic Province: Regional variations in chemical composition.  Geol. Society of America, Abstracts with programs, vol. 35, no. 3. 

Smith, Robert C., II, 1975. Geology and geochemistry of Triassic diabase in Pennsylvania. Geol. Soc. America Bull., v. 86, p. 943-955.

Eggert, Gerald G., 1994. The iron industry in Pennsylvania. Pa. Historical Studies No. 25, The Pennsylvania Historical Association.

Frazer, Jr., P., 1876. Report of Progress in the District of York and Adams Counties showing the Iron Ore Belts and Individual Mines. Pa. Geol. Survey, 2nd ser., Rept. C.

Frazer, Jr., P., 1877.  1875 report of progress in the counties of York, Adams, Cumberland and Franklin.  Pa. Geol. Survey, 2nd ser., Rept. CC.

Chrastina, Paul, 1994.  William Keith's Copper mine: Prelude to the Maryland-Pennsylvania Border War.  Matrix, vol. 3, nos. 5-6 (Fall),  p. 112-116. 

Gibson, John, 1886. History of York County, Pennsylvania. F. A. Battery Publishing Company, Chicago.

Historical Society of York County, 1994. Combined Atlases 1876 York County, Pennsylvania Illustrated and 1903 City of York. Windmill Publications, Inc., Mt. Vernon, IN.

Jones, J., 2001. Welsh Settlers of Delta, PA./Cardiff, MD. Harford Historical Bulletin, no. 89, Summer, The Historical Society of Harford County, Inc., Bel Air, MD.

de Wet, C.B., Dickson, J.A.D., Wood, R.A., Gaswirth, S.B., and Frey, H.M., 1999.  A new type of self margin deposit: rigid microbial sheets and unconsolidated grainstones riddled with meter-scale cavities.  Sedimentary Geology, vol. 128, p. 13-21.

Ganis, R., and Hopkins, D., 1984. Stratigraphy, structural style, and economic geology of the York-Hanover Valley. 3rd Annual Field Trip, Harrisburg Geological Society., Harrisburg.

Ganis, R., and Hopkins, D., 1990. The West York Block: Stratigraphic and Structural setting in 55th annual Field Conference of Pennsylvania Geologists, Carbonates, schists and geomorphology in the vicinity of the lower reaches of the Susquehanna River, Charles Scharnberger, editor. Harrisburg, PA.

Jandorf, M. L., 1912. Preliminary report on the York Valley limestone belt in York County, Pennsylvania. Pa. Geol. Survey, 4th ser., Report for 1910-1912. p. 50-129.

Jones, Jeri l., Unusual sinkhole occurrence at Rudy County Park, York County, Pennsylvania.  Pa. Geology, vol.11, no. 4.

Kochanov, W.E., 1995. Sinkholes and karst-related features of York County, Pennsylvania. Pas. Geol. Survey, 4th ser., Open-File Rept. 95-06.

Kochanow, W.E., 1997.  The Mummy's Shroud.  Pennsylvania Geology, vol. 28, no. 1/2, p. 2-8.

Kreiger, W., 1996. Carbonates of the York, Pennsylvania area: A field trip guidebook. Annual Conference of the National Assoc. of Geosciences Teachers, Stanton, DE.

MacLachan, D. B., 1990. Paleozoic carbonates of the continental margin in the Lancaster-York Valley, Pennsylvania in 55th annual Field Conference of Pennsylvania Geologists, Carbonates, schists and geomorphology in the vicinity of the lower reaches of the Susquehanna River, Charles Scharnberger, editor. Harrisburg, PA.

MacLachan, D. B., 1994. Introduction in Various Aspects of the Piedmont Geology in Lancaster and Chester Counties, Pennsylvania. 59th Annual Field Conference of Pa. Geologists, Rodger Faill and William Sevon, editors.

Miller, B. L., 1934. Limestone in Pennsylvania. Pa. Geol. Survey, 4th ser., Min. Res. Rept. 20.

Anne, M. and Schmerling, D., 1978. A Quarry without minerals. Rocks and Minerals, v. 53, no. 3, p. 91-93.

Brown, A.P. and Ehrenfeld, F., 1913.  Minerals of Pennsylvania.  Pa. Geol. Survey, 3rd ser., Rept. 9.

Dana, Jamer D., 1850.  A system of mineralogy, 3rd Edition, New York.

Ehrenfeld, C.H., 1890.  Stilbite from York Haven, York County, Pa.  Journal Anal. and Applied Chemistry, vol. 4, p. 157.

Ehrenfeld, C.H., 1890.  Fluorite from York, Pa. Journal Anal. and Applied Chemistry, vol. 4, p. 281.

Ehrenfeld, C.H.,  1893.  Minerals from York Haven, York County, Pa. Journal Anal. and Applied Chemistry, vol. 7, pp. 4-5.

Eyerman, John, 1889.  The mineralogy of Pennsylvania. Easton. 

Foose, R.M., 1945. Manganese minerals of Pennsylvania. Pa. Geol. Survey, 4th ser., Min. Resources Rept. 27.

Genth, Frederick A., 1875.  Preliminary report on the mineralogy of Pennsylvania.   Pa. Geol. Survey, 2nd ser., Report B.

Genth, Frederick A., 1876.  Second preliminary report on the mineralogy of Pennsylvania.   Pa. Geol. Survey, 2nd ser., Report B2.

Geyer, Alan, Smith, R.C., II, and Barnes, J.H., 1976. Mineral Collecting in Pennsylvania. Pa. Geol. Survey, 4th ser., General Geol. Report 33.

Gordon, S., 1922. The mineralogy of Pennsylvania. Acad. of Natural Sciences of Phila., Spec. Pub. No. 1.

Hall, Charles E., 1878. Catalogue of the Geological Museum: Part 1. Pa. Geol. Survey, 2nd ser., Rept. O.

Holden, E., 1919. Limonite pseudomorphs after pyrite from York County, Pennsylvania. Am. Min., v. 4, p, 68-69.

Jandorf, Morton L., 1920.  Unusual minerals in limestone near York, Pa.  American Mineralogist, v. 5, p. 196.

Lapham, D. M., and Gray, C., 1972.  Geology and origin of the Triassic magnetite deposit and diabase at Cornwall, Pennsylvania.  Pa. Geol. Survey, 4th ser., Min. Res. Rept. 56.

Lininger, Jay L., 1997.  The history of an obscure Pennsylvania rutile occurrence.  Matrix Magazine, vol. 5, no. 3 (Fall),  p. 115-119. 

McCreath, Andrew S., 1879. Second Report of Progress in the Laboratory of the Survey at Harrisburg. Pa. Geol. Survey, 2nd ser., Rept. MM.

Oles, F. and Oles, H., 1967. Eastern Gem Trails. GemBooks, Mentone, CA. 80 p.

O'Neil, B. J., and Smith, R. C., II, 1973. A new Triassic copper occurrence at Rossville, Pennsylvania. Pennsylvania Geology, v. 4, no. 1, p. 6-7.

Smith, Robert C., II, 1973.  A new Triassic copper occurrence at Rossville, Pennsylvania.  Pa. Geology, vol. 4, no. 1.

Smith, Robert C., II, 1977. Zinc and lead occurrences in Pennsylvania. Pa. Geol. Survey, 4th ser., Min. Res. Rept. 72.

Smith, Robert C., II, 1978. The mineralogy of Pennsylvania: 1966-1975. Spec. Publication #1. Friends of Mineralogy - Pennsylvania Chapter.

Stose, George W., and Glass, J. J., 1938. Garnet crystals in cavities in metamorphosed Triassic conglomerate in York County, Pennsylvania. Amer. Mineralogist, v. 23, p. 430-435.

Berkheiser, Jr., S.W., 1983.  Reconnaissance survey of potential carbonate whiting sources in Pennsylvania.  Pa. Geol. Survey, 4th ser., Mineral Resource Rept. 83.

Berkheiser, Jr., S.W., 1985. High-Purity Silica Occurrences in Pennsylvania. Pa. Geol. Survey, 4th ser., Mineral Resource Report 88.

Berkheiser, Jr., S.W., and J.H. Barnes, 1989. Nonmetals - Clay and Shale in The Geology of Pennsylvania, Charles Shultz, editor. Harrisburg, Pa. pp. 605 - 613..

Berkheiser, Jr., S.W., and J.H. Barnes, and Smith, R.C. II, 1985. Directory of nonfuel mineral producers in Pennsylvania. Pa. Geol. Survey, 4th ser., Information Cir. 54, 4th ed.

Bining, Arthur C., 1979. Pennsylvania iron manufacture in the Eighteen Century. Pa. Historical and Museum Commission.

Cloos, E., Freedman, J., Hole, G., Hover, K., Hosterman, J., Nelson, A., Sims, S., and Wise, D. 1968. The geology of mineral deposits in south central Pennsylvania. 33rd Annual Field Conference of Pennsylvania Geologists Guidebook, Pa. Geol. Survey

Freedman, Jacob, 1968. Bender's Quarry - Mt. Holly Springs, Pennsylvania in The geology of mineral deposits in south-central Pennsylvania. 33rd Annual Field Conference of Pennsylvania Geologists Guidebook, Harrisburg.

Freedman, Jacob, 1989. Nonmetals - Dimension Stone in The Geology of Pennsylvania, Charles Shultz, editor. Harrisburg, Pa. pp. 599 - 604.

Harder, E.C., 1910. Deposits of brown iron ore near Dillsburg, York County, Pennsylvania. U.S. Geol. Survey, Bull. 430.

Harder, E.C., 1910a. Structure and origin of the magnetite deposits near Dillsburg, York County, Pennsylvania. Econ. Geol., v. 5, p. 599-622.

Henderson, C. H., 1884. The copper deposits of the South Mountain, Pennsylvania. American Institute of Mine Engineering Transcripts, vol. 12, p.82.

Hoff, D., 1989. Minor Resources in The Geology of Pennsylvania, Charles Shultz, editor. Harrisburg, Pa. pp. 645 - 655.

Hopkins, D., 1985.  Refractory dolomite production in southeastern Pennsylvania - The J. E. Baker Co.  Pennsylvania Geology, Vol. 16, no. 3, p. 2 - 4.

Hopkins, D., and Ganis, G. R., 1990. Mineral resources of York County, Pennsylvania in 55th annual Field Conference of Pennsylvania Geologists, Carbonates, schists and geomorphology in the vicinity of the lower reaches of the Susquehanna River, Charles Scharnberger, editor. Harrisburg, PA.

Hosterman, J.W., 1968. White clay deposits near Mt. Holly Springs, Cumberland County, Pennsylvania in Guidebook for the 33rd Annual Field Conference of Pennsylvania Geologists: The geology of mineral deposits in south-central Pennsylvania. Harrisburg.

Hosterman, J.W., 1984. White Clays of Pennsylvania. U.S.G.S. Bull. 1558-D,
pp. 13-15.

Hotz, Preston E., 1949. Diamond-drill exploration of the Dillsburg magnetite deposits York County, Pennsylvania. U.S. Geol. Survey Bull 969A

Jandorf, M. L., 1913. Copper in York County, Pennsylvania. Mining Science Press, v. 106, p. 346-347.

King, A., 1986. York's Stone Buildings: Geology and architecture. York Rock and Mineral Club, Spec. Pub 3.

Leighton, H., 1934. The white clays of Pennsylvania. Pa. Geol. Survey, 4th ser., Bull. Progress Rept. 112.

Leighton, H., 1941. Clay and shale resources in Pennsylvania.  Pa. Geol. Survey, 4th ser., Bull. M 23.

Neumann, G. L., 1947.  Investigation of the Dillsburg magnetite deposits, York County, Pennsylvania.  U. S. Bureau of Mines Rept. of Investigation 4145.

O'Neill, Jr., Bernard J., Lapham, Davis M., Jaron, Michael G., Socolow, Arthur A., Thomson, Robert D., and Hamlin, Howard P., 1965.  Properties and uses of Pennsylvania shales and clays.  Pa. Geol. Survey, 4th ser., Mineral Res. Rept. 51.

Spencer, Arthur A., 1908. Magnetite deposits of the Cornwall type in Pennsylvania. U.S. Geol. Survey Bull. 359.

Stone, R. W., 1923. Roofing granules industry in southeastern Pennsylvania. Pa. Geol. Survey, 4th ser., Bull. 82.

Stose, G. W., 1910. Copper deposits of South Mountain in southern Pennsylvania. U. S. Geol. Survey Bull. 430, pp. 122-131

PARK GUIDES

Hoskins, D. M., 1978. Gifford Pinchot State Park, Pa. Geol. Survey, 4th ser., Pa Trail of Geology, Park Guide 10.

Inners, J. D., 1983. Geologic Guide to Samuel S. Lewis State Park, York County, Mt. Pisgah and the Lower Susquehanna River Valley, Pa. Geol. Survey, 4th ser., Pa. Trail of Geology, Park Guide 17.

Jones, Jeri L., 1983.  Self-guiding geologic trail at Richard M. Nixon County Park near Jacobus, PA.  York County Parks trail guide.

Crawford, Maria L., 1987. The Wissahickon Schist type section, Wissahickon Creek, Philadelphia, Pennsylvania in Roy, David C., Centennial Field Guide Volume 5 - Northeastern Section of the Geological Society of America, Boulder CO

Faill, R., 1994. Introduction in Various Aspects of the Piedmont Geology in Lancaster and Chester Counties, Pennsylvania. 59th Annual Field Conference of Pa. Geologists, Rodger Faill and William Sevon, editors.

Freedman, Jacob, Wise, B. U., and Bentley, R. D., 1964. Pattern of folded folds in the Appalachian Piedmont along the Susquehanna River in Geologic Investigations of the Pennsylvania Piedmont, Pa. Geol. Survey, 4th ser., Gen. Geol. Rept. G46.

Gohn, G. S., 1973. Metasedimentary units of the Marburg Formation, York County, Pennsylvania. Unpub. M. S. Thesis, University of Delaware, 60 p.

Jonas, A.I., and Knopf, E.B., 1923. Stratigraphy of the crystalline schists of Pennsylvania and Maryland. Amer. jour. Science, 5th ser., v. 5, p. 40-62.

Knopf, E. B., and Stose, A.I., 1929. Geology of the McCalls Ferry-Quarryville district, Pennsylvania. U. S. Geol. Survey Bull. 799.

Thompson, G. H., 1990. Geomorphology of the Lower Susquehanna River gorge in 55th annual Field Conference of Pennsylvania Geologists, Carbonates, schists and geomorphology in the vicinity of the lower reaches of the Susquehanna River, Charles Scharnberger, editor. Harrisburg, PA.

Valentino, D. W., 1990. Post- Taconian structure of the western Piedmont Province of Pennsylvania: The Tucquan Antiform, the Lancaster Valley Tectonite Zone and the Peach Bottom Structure in 55th annual Field Conference of Pennsylvania Geologists, Carbonates, schists and geomorphology in the vicinity of the lower reaches of the Susquehanna River, Charles Scharnberger, editor. Harrisburg, PA.

Valentino, D. W., and Faill, R., 1990. Geologic structures and metamorphism mapping the elusive isograds in the Pennsylvania Piedmont. Pennsylvania Geology, V. 21, no. 3, p. 6-14.

Valentino, D. W., and Maclachland, D., 1989. Tectonics and terranes of southeastern Pennsylvania. Geol. Society of America Abstracts with Programs, vol. 21, p. 13.

Agron, S. I., 1950. Structure and petrology of the Peach Bottom Slate, Pennsylvania and Maryland, with its environment. Amer. Geol. Soc. Bull., v. 61, p. 1265-1306.

Behre, C. H., 1933. Slate in Pennsylvania. Pa. geol. Survey, 4th ser., Bull. M16.

Kappele, William A., 2002.  Slate: A Practical Gem.  Rock and Gem, vol. 32, no. 10 (October 2002), pp. 30-35.

SOUTH MOUNTAIN SECTION GEOLOGY

Berkeiser, Jr., S.W., and Smith, R.C., II, 1991. Geology of the Blue Ridge Mountains, Pennsylvania in Guidebook for the 56th annual Field Conference of Pennsylvania Geologists - Geology of the South Mountain Area, Pennsylvania, William Sevon and Noel Potter, Jr., editors. Harrisburg..

Drake, A.A., Jr., 1999. Precambrian and Lower Paleozoic metamorphic and igneous rocks - South Mountain and Reading Prong in The Geology of Pennsylvania, Charles Shultz, editor. Harrisburg, Pa. pp. 37-50.

Fauth, J.L., 1978. Geology and mineral resources of the Iron Springs area, Adams and Franklin Counties, Pennsylvania. Pa. Geol. Survey, 4th ser., Atlas 129c.

Freedman, J., 1967. Geology of a portion of the Mt. Holly Springs Quadrangle, Adams and Cumberland Counties, Pennsylvania. U.S.G.S. Prof. Paper 650-B.

Key, M.M., 1991. The Lower Cambrian clastics of South Mountain, Pennsylvania in Guidebook for the 56th annual Field Conference of Pennsylvania Geologists - Geology of the South Mountain Area, Pennsylvania, William Sevon and Noel Potter, Jr., editors. Harrisburg..

Potter, Jr., N., Hanson, H., Ackermann, R., Dockter, G., Lev, S., Pezzoli, L., and Troy, T., 1991. Stop 8 -Hammond's Rocks in Guidebook for the 56th annual Field Conference of Pennsylvania Geologists - Geology of the South Mountain Area, Pennsylvania, William Sevon and Noel Potter, Jr., editors. Harrisburg..

Root, S.L., 1970. Structure of the northern terminus of the Blue Ridge in Pennsylvania. Geol. Society of America Bull., vol. 81, pp. 815-830.

Smith, R.C., II,, Berkeiser, Jr., S.W., and Barnes, J.H., 1991. Pennsylvania's Version of the Catoctin Metabasalt Story in 56th Annual Field Conference of Pennsylvania Geologists Guidebook - Geology in the South Mountain Area, Pennsylvania, William Sevon and Noel Potter, Jr., editors.

Way, J.H., 1986. Your guide to the geology of the Kings Gap area, Cumberland County, Pennsylvania. Pa. Geol. Survey, 4th ser., Environ. Geol. Report 8.

Wehr, F., and Glover, L., III, 1985. Stratigraphy and tectonics of the Virginia-North Carolina Blue Ridge; evolution of a Late Proterozoic-early Paleozoic hinge zone. Geol. Soc. America Bull., vol. 96, pp. 285-295.

Wilshsen, P. John, and Sevon, W.D., 1981. Giant Ripples at Mount Cydonia. Pennsylvania Geology, vol. 12, p. 2-8.

Cloos, E. and Pettijohn, F. J., 1973. Southern border of the Triassic Basin, west of York, Pennsylvania: Fault or overlap? Geol. Soc. America Bull., v. 84, p. 523-536.

Cope, E. D., 1878. On some saurins found in the Triassic of Pennsylvania by C. M. Wheatley. Proceedings of the American Philosophical Society, v. 17, p.177.

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