CalilorniaState Division of Mines RECEIVED SlP - 41952 LIBRARY Sar, Frarcisco, California _ STATE OF MARYLAND BOARD OF NATURAL RESOURCES DEPARTMENT OF GEOLOGY, MINES AND WATER RESOURCES Joseph T. Singewald, Jr. Director BULLETIN 10 GEOLOGY AND WATER RESOURCES OF PRINCE GEORGES COUNTY SEDIMENTARY DEPOSITS by C. Wythe Cooke SURFACE-WATER RESOURCES by Robert O. R. Martin GROUND-WATER RESOURCES by Gerald Meyer BALTIMORE, MARYLAND 1952 COMPOSED AND PRINTED AT THE WAVERLY PRESS, INC. BALTIMORE, MD., U.S.A. COMMISSION ON GEOLOGY, MINES AND WATER RESOURCES Arthur B. Stewart, Chairman Baltimore G. Victor Cushwa Williamsport Harry R. Hall Hyattsville Joseph C. Lore, Jr Solomons Island Mervin A. Pentz Denton PREFACE One of the projects of the Maryland Geological Survey was a series of county reports dealing primarily with the geology and mineral resources but including brief descriptions of other natural resources supplemented by an atlas of a topographic map, and geologic, soils, and forestry maps printed on the topo- graphic base. The county report and the geologic map of Prince Georges County were published in 1911, the forestry map in 1912, and the soils map in 1913. A completely revised topographic map of Prince Georges County was pub- lished in 1946. The 1911 edition of the geologic map was exhausted in 1947, and the preparation of a new geologic map on the revised topographic base started in 1948. The United States Geological Survey very generously assigned to Dr. C. Wythe Cooke, one of the foremost authorities on the geology of the Atlantic Coastal Plain, the remapping of the geology of Prince Georges County. The revised geologic map was completed in 1950 and published by this Department in 1951. Since the publication of the 1911 report and geologic map, much additional information on the stratigraphy of the Coastal Plain formations had become available. A two-volume Systematic Report on the Upper Cretaceous forma- tions had been published in 1916 by the Maryland Geological Survey. Addi- tional information on the Eocene formations had been published by this De- partment in 1948 in Bulletin 3, Eocene Stratigraphy and Aquia Foraminifera. A study of the sub-surface geology of Southern Maryland was started in 1945 with the inauguration of a systematic investigation of the ground-water re- sources of Southern Maryland under the cooperative program of ground-water studies with the United States Geological Survey. An areal investigation of the ground-water resources of Prince Georges County was begun late in 1948. In view of the more comprehensive understanding of the stratigraphy of the sedimentary deposits in Prince Georges County, it was desirable to supplement the 1911 Prince Georges County report with a further account of the sedimen- tary deposits. Through the generous cooperation of the United States Geological Survey, Dr. Cooke prepared the portion of Bulletin 10 dealing with the geology of those deposits to accompany his new geologic map of Prince Georges County. The publication of this report was postponed waiting for the completion of the report on the ground-water resources of the County. The report on the ground-water resources, prepared by Mr. Gerald Meyer of the cooperative ground-water staff in Maryland, was completed the latter part of 1950 and released for publication to this Department by the United States Geological Survey early in 1952. This report lists with their locations and basic geologic and hydrologic data 502 wells in the County. Additional informa- tion is given in drillers' logs of 179 of these wells and in detailed logs of 32 wells vi Preface from which cuttings samples were obtained and described by the cooperative ground-water staff. The geologic descriptions of the formations in Dr. Cooke's report are augmented by further descriptions of the hydrologic properties of the formations. The report includes a contour map of the surface of the underlying crystalline rock floor on which the Coastal Plain sediments were deposited and structure contour maps showing the depths of the top of the Magothy and Aquia formations, the two most important water-bearing formations in the County. Water level fluctuation trends as disclosed by the records of measure- ments in observation wells and other sources of information are discussed. I he quality of the water in the various water-bearing sands is shown in 55 water analyses. This report enables well drillers and prospective well owners to determine the depths at which ground-water may be obtained, the quantity of water obtainable from the various aquifers, and the probable quality of the water. However, the Department of Geology, Mines and \\ ater Resources can be called upon at any time for such information and for additional data that will be accumulated by the continued inventorying of wells through the opera- tion of the 1945 Well Control Act. The report on the surface-water resources of Prince Georges County was prepared by Mr. Robert 0. R. Martin of the United States Geological Survey on the cooperative stream-gaging staff in Maryland. The first stream flow measurements in Prince Georges County were made on the Patuxent River at Laurel. A gaging station was operated there for two years during 1896 to 1898. Three additional stations in the County were operated for a full year in 1911 to 1912. There are now five stations at which measurements are being made. Two were installed in 1938, and the other three in 1944, 1948, and 1949. The flow measurements prior to 1943 were published by this Department in Bulletin 1, 1944. The records since 1943 are included in this report. Joseph T. Singewald, Jr., Director. CONTENTS Preface Sedimentary Deposits. By C. Wylhe Cooke Introduction Composition Age Previous reports Field work 2 Cretaceous system 2 Lower Cretaceous series 2 Patuxent formation 2 Name 2 Description 2 Stratigraphic relations 3 Paleogeography 3 Fauna and flora 3 Age 3 Distribution 4 Upper Cretaceous series 4 Arundel clay 5 Name 5 Description 5 Stratigraphic relations 5 Paleogeography 5 Fauna and flora 5 Age 6 Distribution 6 Patapsco formation 7 Name 7 Description 7 Stratigraphic relations 7 Paleogeography 7 Flora and fauna 7 Age 7 Distribution 8 Monmouth formation 8 Name 8 Description 8 Stratigraphic relations 9 Paleogeography 9 Fauna 9 Age 9 Distribution 10 Tertiary system 19 Paleocene series 19 Brightseat formation 19 Name 19 Description 20 viii Contents Stratigraphic relations 20 Paleogeography 20 Fauna 20 Age 20 Distribution 21 Eocene series 22 Pamunkey group 22 Aquia greensand 22 Name 22 Description 22 Stratigraphic relations 23 Paleogeography 23 Fauna 23 Age 23 Distribution 23 Nanjemoy formation 29 Name 29 Description 29 Stratigraphic relations 30 Paleogeography 30 Fauna 30 Age 30 Distribution 31 Miocene series 33 Chesapeake group 33 Name 33 Divisions 33 Description 34 Stratigraphic relations 34 Paleogeography 34 Fauna and flora 35 Age 35 Distribution 35 Pliocene (?) series 37 Bryn Mawr gravel 37 Name 37 Description 38 Stratigraphic relations 38 Paleogeography 38 Age 38 Distribution 38 Brandywine gravel 39 Name 39 Description 39 Stratigraphic relations 40 Paleogeography 40 Age 40 Distribution 41 Quaternary system 42 Pleistocene series 42 Contents ix Oscillations of sea level 42 River terracing 43 Terraces along the Potomac River 44 Geologic formations 45 Sunderland formation 45 Name 45 Description 45 Stratigraphic relations 46 Paleogeography 45 Age 46 Distribution 46 Wicomico formation 48 Name 48 Description 48 Stratigraphic relations 48 Paleogeography 48 Flora 48 Age 49 Distribution 49 Pamlico Formation 50 Name 50 Description 50 Stratigraphic relations 50 Paleogeography 50 Age 51 Distribution 51 Late Pleistocene and Recent deposits 51 Description 51 Stratigraphic relations 51 Paleogeography and geography 51 Age 52 Distribution 52 Structure 53 Surface Water Resources. By Robert O. R. Martin 54 Introduction 54 Stream flow measurements 55 Definitions of terms 56 Surface water resources of Prince Georges County 58 Gaging stations in and near Prince Georges County 60 Runoff in Prince Georges County 60 Average runoff 60 Maximum flood runoff 60 Minimum drought runoff 64 Stream flow regulation 64 Discharge records 65 Patuxent River basin 65 1. Patuxent River near Burtonsville 65 2. Patuxent River near Laurel 67 3. Patuxent River at Laurel 70 4. Western Branch near Largo 71 X Contents Potomac River basin 71 5. Northeast Branch Anacostia River at Riverdale 71 6. Northeast Branch Anacostia River at Hyattsville 75 7. Northwest Branch Anacostia River near Colesville 75 8. Northwest Branch Anacostia River near Hyattsville 75 9. Northwest Branch Anacostia River at Bladensburg 79 10. Beaverdam Branch Anacostia River at Kenilworth, D. C 80 11. Henson Creek at Oxon Hill 80 12. Mattawoman Creek near Pomonkey 81 Ground Water Resources. By Gerald Meyer 82 Abstract 82 Introduction 83 Location of the area 83 Purpose and scope of investigation 83 Previous investigations 85 Acknowledgments 85 Geography 85 Culture 85 Climate 86 Physical features 88 General geology and hydrology 88 The geologic formations and their water-bearing properties 92 Pre-Cambrian crystalline rocks 92 Cretaceous system 94 Lower Cretaceous series 94 Patuxent formation (Potomac group) 94 Upper Cretaceous series 95 Arundel clay (Potomac group) 95 Patapsco formation (Potomac group) 96 Magothy formation 98 Monmouth formation 99 Tertiary system 99 Paleocene series 99 Brighseat formation 99 Eocene series 99 Aquia greensand (Pamunkey group) 99 Nanjemoy formation (Pamunkey group) 100 Miocene series 102 Calvert