Bedrock Geolo~~y of the Evitts Creek an ! Pattersons Cree c Quadrangles, M lryland, Pennsylvania, a d West Virginia GEOLOGICAL SURVEY Bl! LLETIN 1173 ; Prepared partly in cooperation with 2 he Maryland Department of Geology, Mines, and Water Resources Bedrock Geology of the Evitts Creek and Pattersons Creek Quadrangles, Maryland, Pennsylvania, and West Virginia By WALLACE nE WITT, ]R., and GEORGE W. COLTON GEOLOGICAL SURVEY BULLETIN 1173 Prepared partly in cooperation with the Maryland Department of Geology, Mines, and Water Resources A detailed discussion of the stratigraphy and structure of the area, and general descriptions of the geologic history and mineral resources UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1964 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director The U.S. Geological Survey Library catalog card for this publication appears after index. For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C., 20402 - CONTENTS Page Abstract__________________________________________________________ 1 Introduction______________________________________________________ 2 Previous investigations_________________________________________ 4 Acknowledgments _____________________________________ -~_______ 7 Topography___________________________________________________ 7 StratigraphY------------------------------------------------------ 8 Ordovician System ___________ ------------------------------- __ 8 Juniata Formation _______________ -------------------------- 8 Silurian System__ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 10 Tuscarora Quartzite________________________________________ 10 Rose Hill Formation_______________________________________ 12 Keefer Sandstone__________________________________________ 15 Rochester Shale---------~--------------------------------- 17 McKenzie Formation _____ ------------------- _________ ---·-· 18 Bloomsburg Red Beds______________________________________ 20 Wills Creek Shale__________________________________________ 24 Tonoloway Limestone____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ 26 Silurian and Devonian(?) Systems_______________________________ 28 Keyser Limestone__________________________________________ 28 Devonian System______________________________________________ 30 Helderberg Group_________________________________________ 30 Coeymans Limestone_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 32 New Scotland Limestone_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 33 Mandata Formation___________________________________ 34 Oriskany Group___________________________________________ 36 Shriver Chert_________________________________________ 37 Ridgeley Sandstone____________________________________ 38 Needmore Shale___________________________________________ 40 Marcellus Shale_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 42 Mahantango Formation____________________________________ 43 Harrell Shale, including the Burket Black Shale Member_______ 48 Woodmont Shale__________________________________________ 51 Chemung(?) Formation_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 53 Structure_________________________________________________________ 55 Folds________________________________________________________ 55 Wills Mountain anticlinorium ____________ ~__________________ 58 Evitts Creek synclinorium__________________________________ 59 Evitts Mountain anticlinorium______________________________ 59 Martin Mountain synclinorium______________________________ 61 Tussey Mountain anticlinorium_____________________________ 63 Mill Run synclinorium_____________________________________ 66 Fautls________________________________________________________ 67 Geologic history__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 72 lll IV CONTENTS Page Economic geology__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 80 Limestone____________________________________________________ 80 Shale and clay_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 81 Siltstone and chert_____________________________________________ 82 Sandstone and quartzite________________________________________ 82 Iron ore______________________________________________________ 83 Oil and gas___________________________________________________ 83 Literature cited_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 84 Index____________________________________________________________ 87 ILLUSTRATIONS [Plates are in pocket] PLATE 1. Geologic map of the Evitts Creek quadrangle_. 2. Geologic map of the Pattersons Creek quadrangle. 3. Stratigraphic section of exposed bedrock in the mapped area. 4. Map of the structural elements in and near the mapped area. Page FIGURE 1. Location of the mapped area______________________________ 3 2. Cresaptown Iron Sandstone of Swartz (1923) near Cabin Run_ 14 3. Bloomsburg Red Beds along U.S. Highway 40_______________ 21 4. Spheroidal weathering in the Mahantango Formation________ 46 5. Contrast in weathering between massive siltstone and silty mudrock in the Mahantango Formation__________________ 47 6. Diagram showing the strike of crests of anticlines and troughs of synclines in the Evitts Creek and Pattersons Creek quad- rangles determined by stereographic projection____________ 57 BEDROCK GEOLOGY OF THE EVITTS CREEK AND PATTERSONS CREEK QUADRANGLES, MARYLAND, PENNSYLVANIA, AND WEST VIRGINIA By WALLACE DE WITT, JR., and GEORGE W. CoLTON ABSTRACT The Evitts Creek and Pattersons Creek quadrangles occupy about 115 square miles of mountainous western Maryland and contiguous parts of Pennsylvania and West Virginia. The exposed strata consist of about 8,000 feet of sedimentary rocks ranging in age from Late Ordovician to Late Devonian. The stratigraphic sequence is divided into 21 formations, several of which are subdivided into members. In ascending order the stratigraphic units are: the Juniata Formation of Ordovician age; Tuscarora Quartzite, Rose Hill Formation, Keefer Sandstone, Rochester Shale, McKenzie Formation, Bloomsburg Red Beds, Wills Creek Shale, and Tonoloway Limestone of Silurian age; Keyser Limestone of Silurian and Devonian ( ?) age; the Helderberg Group (Coeymans Limestone, New Scotland Limestone, and Mandata Formation), Oriskany Group (Shriver Chert and Ridgeley Sandstone), Needmore Shale. Marcellus Shale, Mahantango Forma­ tion, Harrell Shale (including the Burket Black Shale Member in the basal part), Woodmont Shale, and Chemung(?) Formation of Devonian age. The hard and resistant formations .such as the Juniata Formation, Tuscarora Quartzite, and Ridgeley Sandstone commonly form the large hills and moun­ tains in this region. The soft and easily eroded formations such as the Wills Creek Shale, Needmore Shale, Marcellus Shale, and Harrell Shale generally underlie lowlands and valleys. The rocks of the Evitts Creek and the Pattersons Creek quadrangles were deposited in a shallow sea, a part of the Appalachian geosyncline, during the middle of the Paleozoic Era. Source areas east of the geosyncline supplied large amounts of mud, silt, and sand during the accumulation of the red beds of the Juniata Formation in the Late Ordovician and during the deposition of the Tuscarora Quartzite, Rose Hill Formation, and Keefer Sand'Stone during the Early and Middle Silurian. The volume of sand and silt decreased markedly at the close of Keefer time. Calcareous sediments accumulated in the area during much of the Middle and Late Silurian and the Early Devonian. A large and diverse fauna existed in the sea during Rochester time and early McKenzie time when the water was clear and shallow. During the accumulation of the upper part of the McKenzie Formation, the Bloomsburg Red Beds, and the Wills Creek Shale, the environment was unfavorable to many forms of marine life; however ostracodes existed in great numbers. During much of the Late Silurian the sea was smaller than at other times. 1 2 EVITTS, PATTERSONS CREEK QUADRANGLES, MD.-PA.-W. VA. A shallow, well-aerated sea and an abundant food supply gave rise to a large fauna which produced the thick bioclastic limestones of the Keyser at the end of the Silurian and the beginning of the Devonian. Uplift of the source areas early in the Devonian began another westward transgression of clastic sediment. Coarse sand ·became the dominant type of sediment in the .shallow sea during Ridgeley time. Despite the large .volume of coarse-grained detritus carried into the sea, a large and diverse fauna lived in the shallow water. After the deposi­ tion of the Ridgeley Sandstone, a great volume of mud and silt accumulated in the slowly subsiding basin. At times the sea became slightly deeper and its circulation restricted. Black and brownish-black mud rich in organic matter, which accumulated in this euxinic environment, comprises much of the Need­ more Shale, Marcellus Shale, and Burket Member of the Harrell Shale. How­ ever, throughout much of the Middle and Late Devonian, the shallow open sea sorted and winnowed the sediments into the great thickness of alternating beds of gray mud, silt, and fine sand that upon lithification formed the monotonous sequence of greenish-gray rocks of the Mahantango, Harrell, Woodmont,