VIRGINIA DTVISION OF MINERAL RESOURCES PUBLICATION 87

GEOLOGY AND MINERAL RESOURCES OF THE BRANDON AND NORGE QUADRANGLES, VIRGINIA

Gerald H. Johnson and C. R. Berquist, Jr.

COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS AND ENERGY DIVISION OF MINERAL RESOURCES Robert C. Milici, Commissioner of Mineral Resources and State Geologists

CHARLOTTESVILLE. VIRGINIA 1989 VIRGINIA DTVISION OF MINERAL RESOURCES PUBLICATION 87

GEOLOGY AND MINERAL RESOURCES OF THE BRANDON AND NORGE QUADRANGLES, VIRGINIA

Gerald H. Johnson and C. R. Berquist, Jr.

COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS AND ENERGY DIVISION OF MINERAL RESOI.JRCES Robert C. Milici, Commissioner of Mineral Resources and State Geologists

CHARLOTTESVIT I E, VIRGIMA 1989 FRONT COVER: Intertidal sediments of the Bartramsville Member, Bacons Castle Formation exposed at the east side of the Little Cteek Reservoir dam, Feburary 1989. VIRGINIA DIVISION OF MINERAL RESOURCES PUBLICATION 87

GEOLOGY AND MINERAL RESOURCES OF THE BRANDON AND NORGE QUADRANGLES, VIRGINIA

Gerald H. Johnson and C. R. Berquist, Jr.

COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS AND ENERGY DIVISION OF MINERAL RESOURCES Robert C. Milici, Commissioner of Minerat Resources and Sate Geologists

CHARLOTTESVILLE, VIRGIMA 1989 DEPARTMENT OF MINES MINERALS AND ENERGY RICHMOND, VIRGINIA O. Gene Dishner, Director

DIVISION OF MINERAL RESOURCES CHARLOTTESVILLE, VIRGIMA Robert C. Milici, commissioner of Mineral Resources and State Geologist

DEPARTMENT OF PURCHASES AND SUPPLY RICHMOND, VIRGINIA

Copyright 1989, Commonwealth of Virginia

Ponions of the publication may be quoted if credit is given to the Virginia Division of Mneral Resources. CONTENTS

Page I 1 2 5 6 9 Eastover Formation ...... 9 9 Yorktown Formation 9 Bacons Castle Formation ...... 11 Moorings unit ...... t2 t2 Windsor Formation ...... t2 Charles City Formation ...... 13 Chuckatuck Formation ...... t4 Shirley Formation l5 Tabb Formation ...... l6 Sedgefield and Lynnhaven Members l6 Poquosan Member 16 16 L7 L9 19 20 Appendix I: Type 22 Appendix II: Geologic summary of subsurface data...... 24

ILLUSTRATIONS

Plate 1. Geologic map of the Brandon and Norge quadrangles, Virginia in pocket

Figure Page l. Map showing the location of the Brandon and Norge quadrangles 2 2. Map showing the name of surrounding quadrangles and published quadrangle geologic maps ...... 2 3. Map showing the principal geomorphic features in the Brandon and Norge quadrangles 3 4. Exposure showing collapse of overlying materid into Yorktown deposits ...... 6 5. Exposure of Yorktown shell bed and "ghostn sand at Little Creek Reservoir I I 6. Exposure of Shirley Formation in the Little Creek Reservoir ...... 15

TABLES

1. Summary of the geomorphic nomenclature in the Brandon and Norge area ...... 4 2. Summar of snatigaphi 7 3. Geologic formations and their sedimentary and morphologic properties in the Brandon and Norge area ...... I GEOLOGY AND MINERAL RESOURCES OF THE BRANDON AND NORGE QUADRANGLES, VIRGINIA

Gerald H. Johnsonr and C. R. Berquist, Jr'

ABSTRACT subsidence caused by dissolution of carbonates and ground- water with drawal (water mining), and groundwatercontami- The Brandon andNorge 7.5-minute quadrangles are nation from the infiltration of sewage effluents and saniary located on the lower Coastal Plain of southeastem Virginia in landfill leachate. locally, peat at shallow depth, high surfi- tlp counties of Charles City, James City, Prince George, and cial groundwater tables, and shrink-swell soils pose problems York. The arearanges in elevation from slightlyover 140 feet for construction ofbuildings and other strucnres. in the Norge Wlands to sea level along the James and Chickahominy rivers. Except for a portion of York County in the Norge quadrangle which drains into the York River, INTRODUCTION surface water flows into the James River and its tibutaries. The Norge uplands represents the highly dissected remnants The Brandon and Norge 7.5-minute quadrangles of a marine plain. The lower t€rrain is dominated by a (Figure l) are located on the Middle Atlantic Coastal Plain of succession ofterraces that are separated from one another by southeastern Virginia. With the exception of small portions river-parallel scarps. in Prince George and York counties, the Brandon and Norge Formations exposed in the Brandon and Norge quadrangles lie within Charles City andJames City counties. quadrangles include the Eastover (Upper Miocene), York- Inngitudes 77t0' and 76%5' west and parallels 37'15' and town (I-ower and Upper Pliocene), Bacons Castle (Upper 3722'30 north bound the study area. Although ourism and Pliocene), Moorings (Upper Pliocene (?)), Windsor and retail sales are the leading soruces of income, most. of the Charles City (.ower Pleistocene), Chuckatuck (Lower or areais rural with forestry, farming, fishing, and hunting as the Middle Pleistocene), Shirley (Middle Pleistocene), Tabb principal industries. A second-growth, mixed hardwood- (Upper Pleistocene), and Holocene deposits. The Tertiary pine forest coven approximately 80 percent of the land area. formations were deposited under marine o marginal marine Com, soybeans, wheat, and badey are the principal crops conditions whereas the Pleistocene and Holocene sediments grown on the moderately o well-drained soils along the formed in valleys that had been excavated during preceding James River and the adjoining interfluves. Only small settle- glacial lowstands of sea level. The Quaternary deposits, each ments are present in the area Interstate Highway 64, U. S. of which generally exhibits an upward-fining sequence, Highway 60,andStateHighway 5 aretheprincipal highways; formed under fluvial-estuarine conditions during periods of numerous secondary roads cross the area. The Chesapeake relatively higher sea level. and Ohio Railway services the area and coal is the principal Sand and gravel is the principal economic mineral freight. Except for Little Creek reservofu, no other major resource mined from the Brandon and Norge areas. l.arge utility occurs in the area. quantities of this material are extracted from the Shirley The surface runoff in the Brandon and Norge quad Formation in Charles City County, but less pure, more vari- angles flows primarily into the Chickahominy River and then able sand and gravel deposis with less utility are present in into the James River but a small portion drains northward inlo the lower portions of the Bacons Castle, Windsor, Charles the York River. TheJames River crosses the Brandon quad- City, and Tabb formations in this area. Clay from the Shirley rangle from northwest to southeast and the Chickahominy Formation has numerous structuml and utilitarian useg none River flows from north to south along the common boundary is being mined at the present time. Relatively thin, impure of the two quadrangles. The Chickahominy River covers lime and glauconite deposits occur beneath a thick cover of about 8.5 square miles of the quadrangles. Although the Bacons Castle Formation in the Norge uplands. James and Chickahominy rivers in the study area have an Groundwater is extracted from aquifers in the average tidal range of 2.8 feet, neither have significant salt- Chesapeake, Pamunkey, and Potomac grcups and Pleisto- water influx except in time of extreme drought. Marshes cene deposits. Geologic hazards in the Brandon and Norge fringe the rivers and occupy the lower reaches of most smaller quadrangles include storm flooding in lowJying areas, shore- streams in the area; in addition to their aesthetic and ecologic line recession from stream erosion and mass wastage, land value, the marshes reduce erosion and flooding (Moore,

Department of Geology, College of William and Mary, Williamsburg, Virginia 23L87 Division of Mineral Resources, Department of Geology, College of William and Mary, Williamsburg, Virginia 23187 VIRGIMA DIVISION OF MINERAL RESOURCES

1980). Swamps and floodplains usually occrn upsream from would also like to thank Wayland Bass, Henry Stephens, the marshes. The principal drainages in the Brandon and Deward ldartin and their saff of James City County for quadrangles Norge are Kennon, Barrows, Morris, Tomahund" access !o maps and engineering reports; Tcrry lzm of lvlal- Yarmouth, and Powhatan creels. Little Creek Reservoir, com Pirnie Engineers for engineering daca at the Little Creek completed in 1980 and owned by the City of Newport News, Reservoir; Ilarold Matthews and William E. Dvorak of Old has a surface area ofapproximately 800 acres. Dominion Soil Consulants,Inc., and Art Russnow of Rus- snow-Kane and Associates, Inc., for boring samples at the James City County landfill. In addition, Tom Rodgers, Vir- ginia Power Company, and N. L. Hofrneyer, farmer, provided boring daa from their files. Iarry Nester of Henry S. Bran- scombe, Inc., was particularly helpful in providing informa- tion on the operation of their pits in Charles City County. Robert L. Hodges, Soil Scientist, Department of Agronomy,Virginia Polytechnic Institute and State Univer- sity, and Irster L. Seglin and John Mihalcoe, Jr., U.S. Deparunent of Agricultrne Soil Conservation Service, made soil surveys information available to the writers. Donald L. Brime of the Virginia Commission of Game and Inland Fisheries permifted access to the Chickahominy Slate Wild- Figure 1. Map showing the location of ttre Brandon and life Management Arca Drew Meng, U.S. Geological Sur- quadrangles Norge in Charles Ciry (A), James City (B), and vey, provided water well data and helpful discussion on Prince George (C) counties, Virginia groundwater problems. The writers wish to express their gfa[eful appreciation to the numerous farmers, hunt clubs, Eugene K. Rader and D. A. Hubbard of the Virginia and landowners for access to their property. The quadrangles Division of Mineral Resources initiated thegeologic investi_ to the east and southeast (Figure 2) were mapped by Bick and gation in quadrangle the Norge and assisted with later field Coch ( I 969) and others. lvlarilyn A. Johnson and lvlary Ellen work. Field work by the writers began in the fall of l g7g and lvlagary typed the draft of the manuscript. continued intermittently through September, l9gg. Natural and man-made exposures provided derailed sedimentologic and sratigraphic information. Subsurface daa were ac_ s o quired by several methods: over 500 hand-auger a/ holes as a' ^0 deep as 37 feeti 60 power-auger holes, as deep as V4 fegV lg ^a' /si split-spoon/hollow-stem auger holes, as deep as 127 feet;and ""-t +' 2 20 c continuous-sample split-spoon holes, as deep as 65 feef A ^o summary of subsurface data is provided in Appendix II. "3o ^z' .s". Cr" During the construction of the Little Creek Reservoir, Ber- "-. quist examined approximately 40 miles of continuous expo. "$; sure along the shoreline of the reservoir. Berquist "+ a? tt*""u and ^{' Ramsey (1985) and Ramsey (1938) srudied the srrarigaphy ^o' of the Bacons york-James peninsula '*T. Castle Formation on the ""tt N N *+j,l''' and much of their work is reflected in the discussion of the :fi:,,i:i:li:O. .\ -s formation in this reporl Becky Darton, Michelle Dewey, ,9^ 4. d! r':.rij r:;S,: 4i :.'lr:;.;vi::.:t Kathleen Farrell, Eileen ."i; $' :.::i;: {v::.:i:;i: Sullivan, and geology students at the $"d -aG -9 a College of William and Mary assisted the writers in field and t'u" *fi:ti:i laboratory work. Kelvin Ramsey provided a significant contribution in drilling, laboratory work, library research, Figure 2. Diagram showing the quadrangles surrounding soils analysis, and fossil identihcation in the Norge quad- Brandon and Norge and the published geologic maps (shaded). rangle. Eugene Rader, Virginia Division of Mineral Re- sources, Wayne Newell and Lauck Ward, United States MORPHOLOGY Geological Survey, Kenneth F. Bick, College of William and Mary, Pamela C. Peebles, Virginia Department of Transpor- The opography of Brandon and Norge quadranglas tation, and Nicholas K. Coch, Queens College, provided is characterized by a succession of plains and intervening helpful discussion on the stratigraphy of the area. The writers scarps (Figure 3). hevious workers (Clark and Miller, I 9 12; PUBLICATION 87

Wentworth, 1930; Roberts, L932: Bick and Coch, 1969; erosion have created a rolling terrain of knobs and broad Johnson, 1969, 1972, 1976; Johnson and others, 1980) recog- ridges with crests at 110 !o 132 feeq local reliefis 80 feet. nized the stair-stepped nature of the landscape on the York- Steep-sided V-shaped valleys occur in the upper reaches of James Peninsula (fable 1). The undissected portions of flats streams; downstream these valleys are filled with Holocene or plains represent the upper surface of aggradational sedi- floodplain, swamp, and marsh sediments forming flat-bot- mentary sequences and the scarps are the product of shoreline tomed valleys. erosion. The flats decrease in elevation o the southeast and Sediments of the Bacons Castle Formation and the toward adjoining master streams. The highest flats occur in Moorings unitunderlie theNorge upland" TheNorge uplands the northern portion of the Brandon and Norge quadrangles; is separated from the l-ackey plain by the Surry scarp (Bick adjacent flats generally decrease in elevation southward to and Coch, 1969; Johnson and others, 1980). The scarp, which the James River and toward the Chickahominy River. Sub- was originally defined by Wentrvorth (1930) as a coast-wise sequent to their formation, the scarps and plains have under- scarp, is now recognized along the James River and major gone erosion and colluviation. streams in southeastern Virginia. In the Norge and Brandon

Figue 3. Map showing the principal geomorphic features in ttre Brandon and Norge quadrangles. Explanation: Scarps - hachured line, line on top of scarp; 1 - Norge uplands; 2 -Lrc,key plain; 3 - Grove plain; 4 - Grafon plain; 5 - llampon flat @ancing Point flat); 6 - Mulberry Island flat (Shield Point flat); 7 - Huntington flat; 8 - Todds flaq Black - marsh, swamp, and floodplain.

The Norge uplands (Johnson and others, 1980) quadrangles, the scarp is highly dissected and therefore occurs in the northern portion ofthe study area and is exlen- commonly difficult o recognize in the field. The scarpis well sively developed on the quadrangles to the northwest. This preserved in the Providence Forge and Durch Gap quad- undissected plain in the Seven Pines and Durch Gap areas to rangles to the west and northwest where the tde of the scarp the west (Figure 2) is about 165 feet above sea level; its lies at an elevation of approximately 95 feet. The James River surface decreases in elevation eastward to approximately 148 cut the scarp during the time of deposition of the \Vindsor feet in the eroded uplands in the Norge and Toano quad- Formation. rangles. In the Nuge uplands mass wastage and stream The l^ackey plain (Johnson, 1976) is representedby VIRGIMA DIVISION OF MINERAL RESOURCES

the upland at the Chickahominy State Wildlife lVlanagement 75 to 80 feet. The crcst of the scarp ranges from 90 ferltto Area and by broad flats in the southem portion of the Norge more than 150 feer The slope on the scarp is gentle (6 feet per quadrangle (Figure 3). The plain slopes gently from 93 feet mile) to steep (120 feet per mile). Reentrants along the scarp (near the Surry scarp) !o less than 80 feet on is southern have been cut by small fansverse streams. Shoreline erosion margin but exhibits no appreciable slope to the east. Deep at the time of deposition of the Charles City Formation stream valleys with more than 80 feet of relief have been cut formed the scarp. into the Lackey plain. The surficial deposit over most of the Remnants of the Grove plain (Johnson, 1972) are yorklown plain is theWindsorFornation; locally the Forma- found on the uplands lo the south of Cherry }Iall, at Mount tion crops out along the valley walls. Airy, southwest of Holdcroft @igure 3) and as ruurow ter- TheRuthville scarp, herein named for the villageof races along Little Creek that are too small to illustrate; Ruthville in Charles City County, divides ttre Lackey plain fragments also occur along small sneams elsewhere but have from the subjacent Grove plain. The scarp rends subparallel not been mapped. In the Cherry Hall area, the Grove plain is !o the course of the James River from James City County !o rolling and slopes southward from 74 feet 0o less than 60 feer Richmond. The elevation of ttre toe of the scarp varies from Although weakly developed in the Brandon quadrangle,lin-

Wentworth,1930 Oaks and Coch, 1973, Johnson and others, 1981, Roberts, 1932 1987 1987; this report

Prince George upland Sunderland tanacg Norge uplands Sussex plain

Surry scarp Surry scarp

Lackey plain

Ruthville scarp

Wicomico terraoe Isle of Wight plain Grove plain

Lee l{all scarp

Grafton plain

Chippokes and llazelton Kingsmill scarp- scarys

Chowan terrace Hall Pocosin flat Huntington flat

Suffolk scarp Suffolk scarp-

Churchland flatand Todds flat Dismal Swamp terrace Fentress rise

Hickory Big Bethel scarp

Deep Creek swale and Hampton flat Mount Pleasant flat

Princess Anne tenace Sand-ridge and Mud-flat Mulberry Island flat complex PUBLICATION 87 ear ridges are prominent on the Grove plain in the Charles of the low relief, broad flat, fine-grained soils, and dense City quadrangle. The small terraces along Little Creek are vegetation. The Huntington flat slopes most steeply within aggradational flats with elevations of67 to 74 feet. Although 0.6 mile of the bounding scarps. The flat is dissected by older sediments crcp outlocally, the Charles City Formation Tomahund, Morris, Kennon, Barrows, Yarmouth, Gordon, is the surficial formation under most of the Grove Plain. and Powhatan creeks. Marshes, swamps, and flood plains A discontinuous, low scarp, the l.ee llall (Johnson, occupy the lowlands. The surficial deposits of the Hunting- 1972), trends parallel to the middle reach of Barrow Creek on flat are the clayey sand and locally gravelly sand of the and divide.s the Grove and higher plains ftom the Grafton Shirley Formation. Plain. No clerly defined scarp exists between the Grafton The Suffolk scarp (Flint, 1940) separates the higher and Grove plains south ofCherry tlall (Brandon quadrangle). plain, principally the Huntinglon flat, from the lower Danc- The toe of the scarp is at approximatsly 62 feet. The scarp ing Point flar This scarp has a toe elevation of approximately was formed by shoreline erosion along the James River 25 feet and a crest that exce€ds 3 5 feer The scarp trends east- estuary during deposition of the Chuckatuck Formation. west in the southern pafi of the Brandon quadrangle and is A narow ract of land along the middle reach of found only as isolated remnants elsewhere in the study area Barow Creek and anotrer on the southeastern half of the The scarp was cut by the ancestral James and Chickahominy Cherry Hall upland at 55 to 60 feet are conelated !o the rivers during the l,ate Pleistocene. Grafton Plain on the lower part of the Yort-James Peninsula In the Brandon and Norge quadrangles, the bound- The plain is gently rolling to flat and is underlain by fine- ary between the llampton and Todds flats is not as clearly grained estuarine sediments of the Chuckatuck Formation. defined as on the lower part of the York-James Peninsula The Kingsmill scarp @ick and Coch, 1969) sepa- shown on Figure 3 (Johnson, 1976). The morphological rates the higher plains from the Huntington flat This scarp distinction between these flats is not made in this report and trends subparallel to the James and Chickahominy rivers and they are collectively called the Dancing Point flat (Johnson encircles the uplands near Cherry Hall and the Chickahominy and others, 1980). This flat is characteriznd, by a ridge and State Wildlife Management Area The oe of the scarp ranges swale topography with ridges that rise 5 to 15 feet above the in elevation from 43 feet o 48 feet through much of its length. adjacent swales. The ridges, which diminish in elevation The crest is variable, ranging from 43 feet where the scarp is downstream, range in elevation from?-6 feet to less than 10 indistinct to more than 100 feet where prominent. The scarp feetat theirdownsFeam extremity. Theyexhibitacurvilinear was cut by shoreline erosion along the ancestral James River pattern that varies from subparallel to perpendicular o the during the time of deposition of the Shirley Formation. presentJames River. The swales arepoorly drainedand are The Huntington flat, named by Coch (1971), occu- occupied by intermittent and perennial sreams, marshes, and pies mostof the central and southernportions of the Brandon swamps. The ridges are composed of sand and are mantled quadrangle and the southern portion of the Norge quadrangle with siltsandclayeyfinesandof theSedgefieldandLynnhaven (Figure 3). The flat nearly surrounds the uplands near Cherry members of the TabbFormation. The Dancing Point flat was Ilall, Mount Airy, and the Chickahominy State Wildlife created by fluvial-estuarine processes during the Late Pleis- lvlanagement Area, and extends north-northwestwad along tocene. the Chickahominy River. The undissected flat ranges in The Mulberry Island flat, formerly the Mulberry elevation from approximately 48 feet near the Kingsmill Island ridge and swale (Johnson, 1969), consists of areas with scarp to approximately 33 feet in the cenftal portion of the gently sloping, low-relief opography or with a series of Huntington flar The flu maintains a nearly constant eleva- crnvilinear ridges and swales. The ridges decrease in eleva- tion from east to west. Although the flu does nd possess tion downstream; the swales near sea level are covercd by srongly developed ridge and swale topography typical of marshes and swamps along the Chickahominy River and at lower flats in the Brandon area or that typify the Huntington Kennon Ma$h. The flat mnges in elevation from near sea flat to the west (Chades City and Westover quadrangles), a level to about 12 feet and is well developed along the Chicka- shallow arcuate swale, along Monis Creek, occupies the hominy River atParsons Island,Shields Point,Wrightlsland, cenral portion of the flat. Similarly, ttre rectangular drainage and Old Neck @ate l). The Mulberry Islandflat is underlain pafiern of the ributaries to Morris Creek near Cherry }Iall by the Poquoson Member of the Tabb Formation and was developed between short, low ridges and swales and the deposited under fluvial-esnrarine conditions. longer recurved drainage lines, such as Morris Creek and Holocene landforms in the Brandon and Norge upper Parsons Creek. Small upland swamps, located I mile quadrangles include the lowlands occupied by stream southwest of Mount Airy and elsewhere on the flat, devel- floodplains, estuaries, marshes, and swamps. oped in shallow depressions on the Huntington flat. Head- ward erosion by small streams and ftrom man-made ditches has led to the partial or complete draining of these areas. A STRUCTURE small spit projects into the flat approximately 1 mile south- west of Holdcroft. Much of the flat is poorly drained because The Brandon and Norge quadrangles lie on the VIRGINIA DIVISION OF MINERAL RESOURCES

southwestem flank of the Chesapeake-Delaware embayment (Munay, I 96 I ). The embayment, which developed in Meso- zoic time, is filled with later Mesozoic and Cenozoic sedi- ments. Basement rocks beneath the coastal plain sequeflce are comprised of metamorphic and igneous rocks of paleo- zoic and hecambrian (?) ageand Triassic sedimentary rocks. The coastal plain deposits thicken from less than 30 feet west of Richmond to more than 2500 feet in the Virginia Beach area The deposits are about 900 feet thick along the westem border of the Brandon quadrangle, and increase o over I 100 feet in the eastern part of the Norge quadrangle (Meng and Harsh,l9M). The coastal plain sediments rest on an eastward dipping basement surface cut by Cenozoic faults (Mixon and Newell, 1977). The dip of the formations within the coastal plain sequence decreases progressively with age; the Eas- tover-Yorktown contact has a regional dip of approximately 2.5 feet per mile in ttre study area. The regional dip to the southeast and the reduction in dip in younger deposits of the Figure 4. Photograph of exposure showing collapse of coastal plain indicate ttru ttre continental margin has been overlying material into Yorktown deposits; dark unit is progressively downwarped through much of laterMesozoic brown clay residue of the weathered Yorktown; light unit is and Cenozoic times. the Barhamsville Member of the Bacons Castle Formation. The Brandon and Norge quadrangles lie betrpeen the York-James monocline (Ward and Blackwelder, 1980) and the zone of reverse faulting near Hopewell @ischinger, and Oligocene), Chesapeake Group (Miocene and Pliocene), 1987). Faulting and warping influenced ttre depositional and Pleistocene and Holocene sediments, in ascending order. pattern of sediments in the Yorktown and Chowan River The formations of the Potomac and Pamunkey and the lower Formations (Johnson and others, 1985) during pliocene time. pafi of the Chesapeake goups are known only from deep The gentle eastward dip of the Eastover-yorktown contact, borings in the study area and will not be discussed further. the apparent absence of structural faults and folds within the Definitions and usage of stratigraphic units in ttre Virginia study area, and the lack of discernible warping of Quaternary Coastal Plain have changed over the past 60 years. Table 2 aggradational surfaces suggest that the differential structural summarizes the upper Cenozoic stratigraphic units recog- deformation of the coastal plain during the I-ate Tertiary did nized by various workers since 1928. Lithologic and sedi- not effect this area during the Quaternary (Johnson and mentary characteristics of the stratigraphic unis used in this Peebles, 1984). The progressively higher elevations of older report are presented in Table 3. Quaternary deposits indicate regional uplift of the entire The stratigraphic units exposed atthe surface in the Coastal Plain during the late Cenozoic Era. Brandon and Norge quadrangles include 0re Eastover, York- Sinkhole collapse structures, as much as l0 feet in town, and Bacons Castle Formations of the Chesapeake diameter, are found in the Yorktown, Bacons Castle, Wind- Group, the Moorings unit" and the Windsor, Charles City, sor, and Tabb Formations on the York-James peninsula. Shirley, Chuckatuck, and Tabb Formations and Holocene yorktown Differential dissolution ofcarbonates from the has deposits Clable 2). The Eastover, Yorktown, and Bacons poduced subsidence and collapse structures @gure 4), in- Castle of Late Tertiary age are shees of fossiliferous marine cluding small slump folds, normal faults, and collapse breccia. or tidal-flat sand and silt that crop out in deep valleys in ttre Normal faults with displacements of 2 to 18 inches occur in Norge uplands and on the flanks of the Lackey plain. The the Bacons Castle, Windsor, and Shirley Formations in the Eastover (Upper Miocene) and Yorktown (Pliocene) are Norgeand Brandon quadrangles, and are probably related o mapped together because of the limited exposure and lithol- penecontempomneous compirction, slumpage, and dissolu- ogic similarity of the weathered upper Fastover and lower tion in the underlying Yorktown Formation. Yorktown Formations. The Moorings unitis sporadic in distibution andof problematicage. Each of the Quatemary formations consists STRATIGRAPHY of an upward-fining sequence and, with the exception of the bay deposis of the Windsor, consists of fluvial-estuarine The Coasal Plain seadgraphic sequence in the gravel, sand, clayey silt, and organic-rich sediments. A brief Brandon and Norge quadrangles is comprised of the Potomac summary of the lithologic characteristics of each unit is Group (Cretaceous), Pamunkey Group @aleocene, Eocene presented in Table 3. VIRGIMA DIVISION OF MINERAL RESOI.'RCES souhweslern flank of the Chesapeake-Delaware embayment (Murray, l!)61). The embayment, which developed in Meso- zoic time, is filled with later Mesozoic and Cenozoic sedi- ments. Basement rocks beneath the coastal plain sequefice are comprised of metamorphic and igneous rocks of Paleo- zoic and Precambrian (?) age and Triassic sedimentary rocls. The coastal plain deposis thicken from less than 30 feet west of Richmond !o more ftan 2500 feet in the Virginia Beach arca The deposits are about 900 feet thick along the westem border of the Brandon quadrangle, and increase o over I 100 feet in the eastern part of dre Norge quadrangle (Meng and Ilarsh, 1984). The coastal plain sediments rest on an eastward dipping basement suface cut by Cenozoic faults Mxon and Newell, 1977). The dip of the formations within the coastal plain sequence decreases progressively with age; the Eas- lover-Yorklown concact has a regional dip of approximately 2.5 fentper mile in the snrdy area The regional dip to the southeast and the reduction in dip in younger deposis of the Figure 4. Photograph of exposure showing collapse of cmstal plain indicate that he continental margin has been overlying material ino Yqkown deposits; dart unit is progressively downwarped through mrrch of later Mesozoic brown clay residue of the weathered Yorktown; light unit is and Crnozoic times. the Barhamsville Member of tlrc Bacons CastleFormation. The Brandon and Norge quadrangles lie benveen the York-James monocline (Ward and Blackwelder, 1980) and the zone of reverse faulting near Hopewell @ischinger, and Oligocene), Chesapeake Grcup (Miocene and Pliocene), 1987). Faulting and warping influerrced the depositional and Pleisocene and Holocene sediments, in ascending order. pattern of sedimenS in the Yorkown and Chowan River The formations of the Potomac and Pamunkey and he lower Formations (Johnson and others, 1985) during pliocene time. part of the Chesapeake groups are known only from deep The gentle eastward dip of the Eastover-Yorklown contact, borings in the surdy area and will not be discussed further. the apparent absence of structural faults and folds within the Definitions and usage of stratigraphic units in the Virginia study area, and the lack of discernible warping of euatemary Coastal Plain have changed over the past 60 years. Table 2 aggradational surfaces suggest that the differential structural summarizes the upper Cenozoic sratigraphic units recog- deformation of tlre coastal plain during the Late Tertiary did nized by various workers since 198. Lithologic and sedi- not effect this area during the Quaternary (Johnson and mentary characteristics of the statigaphic unis rsed in ttris Peebles, l9&4). The progressively higher elevations of older r€,port are presented in Table 3. Quaternary &posits indicate regional uplift of the entire The sratigraphic units exposed at the surface in the Coastal Plain during the Late Cenozoic Era. Brandon and Norge quadrangles include he Eastover, York- Sinlfiole collapse strucures, as much as l0 feet in town, and Bacons Castle Formations of ttre Chesapeake diameler, are found in the Ysktown, Bacons Castle, Wind- Group, the Moorings unit, and the Windsor, Charles City, sor, and Tabb Fcmations on the York-James Peninsula. Shirley, Chuckatuck, and Tabb Formations and Holocene Differential dissolution of carbonates from the Yorktown has deposis Clable 2). The Eastover, Yorktown, and Bacons produced subsidence and collapse structur€s (Figure 4), in- Castle of Late Tertiary age are sheets of fossiliferous marine cluding small slump folds, normal faults, andcollapsebreccia. or tidal-flat sand and silt ttnt crcp out in deep valleys in the Normal faults with displacements of 2 to 18 inches occur in Norge uplands and on the flanks of the Lrckey plain. The the Bacons Castle, Virindsor, and Shirley Formations in the Easlover (Upper Miocene) and Yqktom @liocene) are Norgeand Brandon quadrangles, and are probably related to mapped ogether because of the limited exposure and littrol- penecontemporaneous compaction, slumpage, and dissolu- ogic similarity of the weathered upper Eastover and lower tion in the underlying Yorktown Formation. Yorktown Fmrnations. The Moorings unitis spcadic in disribution and of problematicage. Each of the Quatemary formations coruists STRATIGRAPHY of an upward-fining sequerce and, with the exception of the bay deposits of the Windsor, consists of fluvial+stuarine The Cestal Plain sratigraphic sequence in the gravel, sand, clayey silt, and organic-rich sediments. A brief Brandon andNorge quadrangles is comprised of the Potomac summary of the lithologic characteristics of each unit is Group (Crcaceous), Pamunkey Group (Paleocene, Eocene presented in Table 3. PUBLICATION 87 7

a t E ei 9 a o ;5 3s C o OE E r; a : :G o a :o ab io e -o :E s- 3; o a oE !b g E o .E .9L !-aa : E!; C CE E =Eo- o oo Y EE a o OL aa 9 o a ia o EO s!; E . o OE 3E ; l ato t a '

a E aE o 0 a g ! ! F a ! a a o a -Qr e t E i! a a T! ii o o go rt L e o EC 3tE- ! g! o a 2 ao o a aC o E€ 't ah o a o o I ut ! co c cE E 3 uollrruroc :llo|loN a 't E o E e c E c E c I o a o I a I a ! ! t .9 c 9 I E a o . . E E E ! a a a ! a F . a !G f E 9r E L E .9r E g ! F' EE E E E :E o= a E z o o a): o a ! o a I -9O a o: o - €: o o g a L U rt a a o t a) LE I L o L E o L o 6 o .E c I G !q t I o a a c E I aa g E o t :E a z :3 o EE t I I E ! o a :a=a o oo E! o a o o E E! o o a 9L o o o a :L F a A at I a o a ' c o t .} E I a E o c o 6 c a a) a s - o t o E qqlJ 6 (, o qa - t rolltuJOl = @ t a c E u o o E 2 c li E I C E a E o I o . I a a I o o :5 a a i E:9 a a E u E ! a 9r E L 5 E I a 0^ E Ec o I o I (, E E o I {F t E o El o o s€ E I E a a a L B t E J a c a :e o a o ! o Y- 3r ! o ! z c .:} * a a o =i E! o a o . I c a E E . :;i* I a ! o qq3J (, E E I o Y uolllulol =6 o ] E o s iE 6 5 2 ; o c c ] E j C o E ! o D .9 E .9 e! C I E ! ! Ei g C . . - a a ,z I a a -! Z. E I s e E E ! F' --9 .E,F;E g o ! oa E o o a o o (): o E a I a o o a o t a) c !E E !:i e E o ! a .F EL o a E o ZE t E a a a CE €:E o o z! c I E o I a a o o E o o C ! a :a=a oc g;ig L c E a o o a 0 -g o OL :i a c A a o o :EE s C .? o E= C a o o o z C o a 0 a , o I o C' (, s Ei o ! o o x qqlJ =o 3 a ! I E I c rcllauloJ os u EgE g! E a ; E o o t6 ! o j E a E E C !. o u a a e o .9 o ' a E o ! 3,E a c E F^ . . . a o :5 a c I o3 9r t c E (r; aE E o I a o= o o E a o I a oo a a o o 9r a E ri zi rt o a L c L E: E <5 !c t € a a iE9O :! E o a aa g C o ! a 3: -! o E z^e C E :L EE o L EE o o .E L c a a G o to o E> o o :8 i t z E .t o o a o E€ o Z t a T a Ei e ! o 3 qqal z putld, u C E I o rollrulol ilrod.p E v a o f 6 t oU t c a E I t o ! I a E ! a 9a o E E , L a z E E 93 9r E o E co i ta L o o C o a E E; t; a l L 63 E a AE a oE l o

Poquoson 5' tro l0'in ele- massive sands or sandy fluvial-estuarine Member vation (Shields Point fining upward sequence oE! flaO CI E Lynnhaven flats 10'to 20'in ele- sandy fining upward fluvial-estuarine € Member vation @ancing Point s€quence € flat) fl Sedgefield ftas at 25-30 feet lo- basal pebbly sand fluvial-estuarine o a) Member cally with ridge and grades upward into ti swale topography (Todds o fine sandy silt () fla0 A

Shirley flats up to 45' in ele- sand, cobbles grading fluvial-estuarine Formation vation (Huntington flat) upward to clay or clay- ey silt

Chuckatuck flats at elevation of basal pebbly sand fin- fluvial-estuarine Formation 50-62 feet, resricted ing upward into fine in extent (Grafton sand and clayey silt plain)

Charles City dissected flats up to sand grading upward 0o fluvial-esnrarine Formation 75' in elevation; under- clay or clayey silt lies Grove plain

Windsor dissected flats between sand, cobbles grading fluvial-esnrarine Formation 80-lm'in elevation; upward to clay or along James River; underlies L^ackey plain clayey silt bay east ofSurry scarp 2-

Moorings unit dissected dunes and massive sand or silty barier/Mckteyl of Oaks and flats generally be- clay lagoon complex Coch (1973) tween 90 and 125'in elevation; underlies Norge uplands

Bacons Castle underlies Norge uplands; massive to intirbedded various tidal o E Formation generally very dissected sand, silt, and clay; environments a.) Barhamsville flaser to lenticular .E Member bedding common O.

Upperpart of subsurface and low on sand or shelly sand; marine shelf Chesapeake valley walls btown clay marker bed Group at top of Yorktown (Yorktown ('chocolate bed') and Eastover formations) PUBLICATION8T

MIOCENE SERIES tastrea, Dkcinisca, Twritella, arld Ecphora are common. Whale, porpoise, horse, and other vertebrate remains have Eastover Formation been recovered from the upper part of this unit. Isogrnmon is commonly fragmented and abrade{ whereas Glycynuis The Eastover Formation (Upper Miocene) was arf, Scapharca are very commonly articulated. Imbrication named by Ward and Blackwelder (1980) for beds formerly ofplanar shells is common. Although bunows are rare in the assigned o the St Marys Formation in Virginia by Clark and very shelly beds, they are abundant in the silty fine-sand beds. Miller (1912). Within the study area, the formation is com- Dia0oms are sparse. prised of a lower clayey, fine sandy silt, the silty sand facies The upperEastover weathers to a light yellowish- to (Johnson, I 969) or the Claremont IV[anor Member (Ward and light-gray silty fine sand similar to ttrc sand of the overlying Blackwelder, 1980), and an upper interbedded fossiliferous Yorktown. Where the quartz, bone, and phosphate pebbles fine sand and silty fine sand, the shelly sand facies (Johnson, are absent and the fossils are leached, the Yuktown and 1969) and the Cobham Bay Member (Ward andBlackwelder, Easlover are difficult to distinguish in outcrops and in the 1980). The members were considered isochronous by Ward subsurface. Because the lithology of both fumations is and Blackwelder and diachronous by Johnson (1969). The similar, the formations were not mapped separately in the formation crops out locally in deep valleys in the Norge Brandon and Norge quadrangles. The Eastover Formation is upland. unconformably overlain by the Yorktown Formation. The lower part of the Eastover Formation is com- posed of quartzose, clayey, and silty fine sand. Calcite and aragonite, mica, selenite, p)rnte, glauconite, and heavy min- PLIOCENE SERIES erals are present in small amounts. These deposits are dark gray to medium greenish-gray on fresh surfaces but weather Yorktown Formation to a yellowish-brown upon exposure. A sulfurous odor is emitted by the beds. Where the sediments are jointed the The Yorktown Formation was named by Cla* and fractures are stained yellowish- or reddish-brown by iron Miller (1906) for sand and shell beds along the York River oxides. This unit is commonly leached, leaving internal and near York0own, Virginia. Ivlany stratigraphic studies (lvlans- external molluscan molds. Bedding is mostly medium to field, 1943; Johnson, 1969,1972,1976; Ward and Black- thick but is laminated locally. Disrupted bedding caused by welder, 1980; and Johnson and Peebles, 1983) and much burrowing organisms andby the dissolution of shell material paleontologic research (Gardiner, 1943, 1948; Ward and is common. Blow-counts from engineering borings indicate Blackwelder, 197 5, 1980) have resulted in various lithostra- that the sediments are overconsolidated, except where weath- tigraphic and biosratigraphic suMivisions of the Yorktown ered. The lowerEastover is sparsely fossiliferous and many Formation. Johnson (1969, L972, 1976) suMivided the of the body fossils are partially leached, yielding a chalky Yorktown inlo lithofacies based upon mineralogy and texture residue, or are represented by molds or ghosts when com- whereas Ward and Blackwelder (1980) used a combination pletely dissolved. Ecphora, Mercenarid,Turriklla, Glycym- of paleonologic and lithologic features to delineate members eris, Scaplarca, Chesapecten, and numerous other species of the fossiliferous Yorklown. The members are superposed have been identified from this unit. Brtrrows are common. in extensive sheets in the Ward and Blackwelder hierarchy; The lower Eastover is exposed in the deep valleys the facies subdivision (Johnson, 1969) suggests their lateral leading to the Chickahominy River from the Norge uplands intertonguing nature as well as the superposition of certain and in the adjoining Claremont, Surry, and Williamsburg lithosomes. quadrangles. Samples from deep boreholes also indicate its The Yorktown Formation extends from Maryland presence in the study area and that it is at least 26 feet ttrick. to central North Carolina and from the Fall Tnneto beneath The upper fossiliferous Eastover is comprised of the continental shelf. Within the study area the formation interbedded very shelly fine sand and less fossiliferous silty crcps out in valleys in the Norge uplands and in bonow pits. fine sand. The unit is light yellowish-brown to medium gray. Incally, it is also exposed in bluffs along the James River in Quartz, aragonite, and calcite are the dominant minerals; the Claremont, Surry, and Hog Island quadrangles. The glauconile, phosphate, heavy minerals, and mica commonly Yorktown unconformably overlies the Eastover and is in turn constitute less than two percent of the sediment. The bedding overlain disconformably by the Bacons Castle, Windsor, is medium to thin and is accentuatedby the alternation of very Charles City, and Shirley Formations in the Brandon and fossiliferous and sparsely fossiliferous beds. The relation- Norge quadrangles. The contactbetween the Yorklown and ship between the lower and upper Eastover is unclear in the the Bacons Castle is a regional angular unconformity because study area. Quartzose andphosphatic pebbles occur at the top the Bacons Castle rests on progressively older beds of the of this unit. Yorktown and Eastover to the west (Johnson and Peebles, The macrofauna of the upper Eastover is dominated 1984; Berquist and Ramsey, 1985; Johnson and others, by Isognomon: Glycyrrcris, Chesapecten, Scapharca, Sep- 1987a,1987b). The Yorktown is Early and Late Pliocene in l0 VIRGINIA DIVISION OF MINERAL RESOIJRCES

age (Akers, 1972; Ward and Blackwelder, 1980). and matrix supported. Glycynuris mdCrassetella dominate The Sedley Formation at its type and reference the mcrofauna Tte unit is ryproximately 2 feet thick and sections has been found O be composed primarily of weath- grades upward ino the overlying unit. ered and leached Yorktown sediments. For this reason, the Alne Chona-bearing biofragmental sand is com- term Sedley will not be used in this report and it is recom- posed of whole and sand-size shell debris (45 o 80 percent mended that the term be dropped from further usage. calcium carbonate), quartz (10 to 35 percent), and varying A composite section of the yorktown Formation amounts of glauconite and clay. This unit exhibits rudimen- based upon expostrres u the Little Creek Reservoir and the tary bedding, which ranges from medium to thick. The closed Williamsburg Pottery landfill, and from borehole macrofauna is dominated by Clutru, Noetia, Barbatia, and samples is summarized below. The composite thickness of cheilostomatous bryozoans. The bivalves are commonly the fossiliferous Yorktown is approximatsly 43 feet; the articulated andtheCluttu occur in scattered colonies. Thin upper part is weathered and partially covered. Seven littrol- shell-beds with Septastrea and Clwsapecten &qfi spmadi- ogic unis are recognized within the formation: (l) a basal cally within th e C harnaW. The upper part of the C hanabet fossiliferous sand, (2) a very shelly sand, (3) a pebble-bearing is covered and the bed is estimated to be about l0 feet thick. shell bed, (4) a C hama-ichbiofragmental sand, (5) a sparsely This unit is equivalent to the lowerpartof Tnne2,Tunitella fossiliferous, silty, fine sand, (6) a biofragmental sand, and alticostata zone, of lvlansfield (1943) and the Rushmere (7) aweathered unit. These units are progressively beveled Member of Ward and Blackwelder (1980). to the wesl A sparsely fossiliferous, medium gray, silty, fine The basal fossiliferous sand is composed of sparsely sand overlies the Chatna bed. This unit is thick-bedded and fossiliferous fine sand. The sand, which ranges in color from is composed of silt and fine-sand sized quarE, calcium car- a light gray to a light yellowish-brown, is predominately bonate, glauconite, and clay. Locally, thin beds of biofrag- quartz (75 to 90 percent) and calcium carbonate (10 to almost mencal sand and whole shells are interbedded with ttre silty percent). 25 Heavy minerals, glauconite, and mica constitute sand- P seudo clwrna, M ercenaia, and P anopea ae lhe rnost less than two percent of the sediment. Rudimentary bedding, common genera in this unit. Mulinia, Panopea,Dentalium, defined by thin concentrations of shells, is present Cfte- Diodora and whole and broken echinoids occur in the thin sapec te n j effer sonius, P lacopecten clintonius, and C ardi- shelly beds within this unit The silt is extensively bunowed tcnvra granulata are the most abundant species. Ecplura, near the top and the burrows are filled with biofragmental T urrit ella, O str e a, S e ptas tr e a, C lio ru, and encrusting bryozo- sand from the overlying unit The silty sand has a thickness ans are also relatively abundanL This unit grades upward into ofat least 9 feet and is equivalent 0o the upper part of 7nne2 light gray to very yellowish-brown, shelly, fine o coarse of ldansfield (1943) and ttre Morgarts Beach Member of sand. The carbonate content increases to neady 60 percent Ward and Blackwelder (1980). locally and is in the form of whole shells and biofragmenal A biofragmental sand, which disconformably over- sand. The shells are about equally matrix and clast supported. lies the silty fine sand, is composed almostentirelyof calcium Planar shells, such u Clrcsapecten and Ostrea, occur in carbonate (85 to 90 percent); quarE, glauconite, and clay are wave-form with amplitudes of almost three feet and wave- minor components. The carbonate sand is fine !o coarse and lengths of four to ten feet in the Walkers, Surry, Wil- exhibits rudimentary bedding. Colonies of Petaloconchus liamsburg, and Hog Island quadrangles. Chesapectenisthe are prevalent rn this unit; P licatula, M ar ginella, andAnphis- dominate genus in this uniq O str e a, Gly cymeris, C rass e te lla, tegina are common to very abundant The unweathered P lacope cte n, Astarte Jamoftr, Septastrea, articulatedp hacoi-_ portion of ttris bed is approximately four feet thick and grades des,andCarditamcra are common to abundanl l-ocally, the upward ino reddish-brown to medium-brown clayey, fine, aragonitic species have been differentially leached and the sandy silt. Ferricrete and small, disseminated iron oxide calcareous Chesapecten and Osreacemented with a calcite nodules and concretions occur above the biofragmental sand. cemenq these beds t€nd to be resistant and form ledges. The Ward and Blackwelder (1980) assigned this unit to the unit ranges in thickness from 3.3 feet to 5.6 feet thick and Moorehouse Member of the Yorktown. appears disconformable with the overlyrng beds. The lower Weathering of the Yorktown Formation yields dif- two units comprise Zone l,lhe Placopecten clintonfus zone ferent residues depending upon the original mineralogic of Mansfield (1943) and rhe Sunken Meadow Member of composition of the unit, the intensity of weathering, local Ward and Blackwelder (1980). groundwater conditions, and the texture of the sediments. The pebble-bearing shell beds are comprised of The weathering of the Yorktown Formation is differential quartz andbiofragmenal sand and disarticulated shells. euartz and produces a highly undulaory surface with more than l0 and phosphate pebbles, ranging in diameter from 0.2 inch o feet of relief on ttre fossiliferous Yorktown. Leaching of almost 1.0 inch, and bone fragments are sparsely distributed carbonate from the quartz-rich sand of the lower Yorktown at the base of this bed along the James River at Kingsmill, produces a sand almost indistinguishable from the fine sand James City County, atClaremont, Surry County, and in York of the underlying Eastover. Weathering of calcareous beds, County north of Williamsburg. The shells are planar bedded on the other hand, yields a clayey silt or clayey fine-sand PUBLICATION 87 1l residue. This residue is composed of iron and manganese oxides, silt- and fine-sand-sized quartz, and clay minerals. This unit grades downward into partially leached, chalky fossils or rests with sharp contact on unaltered shell beds. Locally, calcareous nodules, 5 to 20 inches in lengtl, have formed in the partially weathered Yorktown. The dissolved carbonate is also precipitated as a cement in the shell beds. The latter produces a craggy, very porous limestone. Where not removed prior to deposition of younger units, the top of the Yorktown is commonly marked by a sequence ofdark-brown muddy sediments up to l0 feet thick. This conspicuous layer, informally known as the "chocolate bed'", is composed of sand, silt" clay, ferricrete, glauconite, manganese oxide (wad), and weathered shells. The accumu- lation of iron- and manganese-oxide-cemented sedimenf (ferricrete) is caused by the reaction of groundwater with calcium carbonate from the shell beds. This brown, muddy, marker bed probably represents subaerial and subterranean dissolution of the Yorktown shell beds and marks the top of the Yorktown Formation. Rogers ( I 884) recognized that this zone "would furnish grounds ifnot confident anticipation of finding marl (Yorktown) beneath." In manyplaces the shells havebeen totally dissolved leaving only a diffuse to detailed outline or "ghost" of the once present shell in a massive fine-sand matrix (Figure 5). Misinterpretation of these leached sediments in earlier re- ports has resulted in the assignment of the material to units other than the Yorktown Formation. Dissolution is active today and most shell-rich outcrops are found at the heads of present drainages. Figure 5. Photograph ofexposure of Yorlxown shell-bed and The Yorktown was depositedduring a succession of leached shell-bed at Linle Creek Reservoir; note pinnacle of marine advances during the Early and late Pliocene Epoch. shell-bed surrounded by fine sand residue with traces of The lower Yorktown accumulated under cool temperate fossils ("ghosts") behind shovel. conditions and the upper parts under subropical or nopical climatic conditions (Ward and Blackwelder, 1980). of the formation has been called the Columbia Group, the Sedley (Oaks andCoch, 1973), andUplanddeposits (Johnson and othen, 1980). Ramsey (1987, 1988) proposed that the Bacons Castle Forrnation Bacons Castle be subdivided into the Barhamsville member (tidal flat deposits) and the Varina Grove member (fl uvial and The Bacons Castle Formation, informally named by estuarine gravel and sand). All of the Bacons Castle sedi- Coch (1965), is comprised of interbedded, intertidal- and ments within the study area are of the BarhamsvilleMember marine-silt, -sand, and -clay that overlie a thin, pebbly or (Appendix I, Section 2). The formation is assigned to the coarse sand. These deposits grade westward into a lower Chesapeake Group in this report. coarse, gravelly" fluvial sand (Berquist and Ramsey, 1985) The Bacons Castle sediments exhibit geat textural and an upper marine-sand, -silt, and -clay sequence (Johnson variability. locally, paleochannels cut into ft e older Tertiary and Peebles, 1985). In western James City and Charles City deposits in the Norge area are filled with sand and gravel, counties, the Bacons Castle rests disconformably on the organic-rich silt and sand, and peat. The base of the formation Yorktown. There is a regional angular unconformity over contains a sporadic, pebbly or coarse sand in western James much of the Yorktown and Eastover Formations in the City and Charles City counties. This unit is overlain by beds Middle Coastal Plain (Johnson and Peebles, 1985; Ramsey, of massive sand, massive to laminated clay, and interbedded 1987). The Bacons Castle Formation is the principal surficial and laminated fine sand, silt and clay, which are variable in deposit beneath the Norge uplands between the Broad Rock thickness and extenl The basal sand is composed principally (Johnson and Peebles, l98l) and Surry scarps; it is mappable of quartz, with lesser amounts of clay, heavy minerals, feld- over much of the Middle Coastal Plain in Virginia and North spar, some of which is kaolinized, and lithic fragments, Carolina (Colquhoun and others, in preparation). Part or all including chert and phosphate, and reworked glauconite. PUBLICATION 87 ll residue. This residue is composed of iron and manganese oxides, silt- and fine-sand-sized quartz, and clay minerals. This unit gades downward into partially leached, chalky fossils or rests with sharp concact on unaltered shell beds. Locally, calcareous nodules, 5 to 20 inches in length, have formed in the partially weathered Yorktown. The dissolved carbonate is also precipitarcd as a cement in the shell beds. The latter produces acra;ggy, very porous limestone. Where not removed prior to deposition of younger units, the top of the Yorklown is commonly marked by a sequence of dark-brown muddy sediments up to 10 feet tlrick. This conspicuous layer, informally known as the "chocolate bed", is composed of sand, silt, clay, ferricrete, glauconite, manganese oxide (wad), and weathered shells. The accumu- lation of iron- and manganese-oxide-cemented sediment (fenicrete) is caused by the reaction of groundwater with calcium carbonate from the shell beds. This brown, muddy, marker bed probably represents subaerial and subterranean dissolution of the Yorkown shell beds and marls the top of the Yorktown Formation. Rogers (1884) recognized that this zone "would furnish grounds ifnot confident anticipation of finding marl (Yorktown) beneath." In manyplaces the shellshavebeen totally dissolved leaving only a diffuse to detailed outline or "ghost" of the once present shell in a massive fine-sand matrix (Figure 5). Misinterpretation of these leached sedimens in earlier re- ports has resulted in the assignment of the material to units other than the Yorktown Formation. Dissolution is active today and most shell-rich outcrops are found at the heads of present drainages. Figure 5. Phoograph of exposure of Yorktown shell-bed and The Yorktown was deposited during a succession of leached shell-bed at Licle Creek Reservoir; note pinnacle of marine advances during tlre Early and Iate Pliocene Epoch. shell-bed surrounded by fine sand residue with races of The lower Yorktown accumulated under cool temperate fossils ("ghosts") behind shovel. conditions and the upper pafls under subtropical or nopical climatic conditions (Ward and Blackwelder, 1980). of the formation has been called the Columbia Group, the Sedley (Oaks and Coch, 1973), and Upland deposits (Iohnson and others, 1980). Ramsey (1987, f988) proposed that the Bacons Castle Formation Bacons Castle be subdivided into the Barhamsville member (tidal flatdeposis) and the VarinaGrove member (fluvial and The Bacons Castle Formation, informally named by esunrine gravel and sand). All of the Bacons Castle sedi- Coch (1965), is comprised of interbedded, intertidal- and mens within fte study area are of the Barhamsville Member marine-silt, -sand, and -clay that overlie a thin, pebbly or (Appendix I, Section 2). The formation is assigned to the coarse sand. These deposits grade westward into a lower Chesapeake Group in this report coarse, gravelly, fluvial sand (Berquist and Ramsey, 1985) The Bacons Castle sediments exhibitgreat 0exhral and an upper marine-sand, -silt, and -clay sequence (Johnson variability. I-ocally, paleochannels cut into the older Tertiary and Peebles, 1985). In western James City and Charles City deposis in the Norge area are filled wittr sand and gravel, counties, the Bacons Castle rests disconformably on the organic-rich silt and sand, and pear The base of he formation Yorktown. There is a regional angular unconformity over contains a sporadic, pebbly or coarse sand in western James much of the Yorktown and EasOver Formations in the City and Charles City counties. This unit is overlain by beds Middle Coastal Plain (Johnson and Peebles, 1985; Ramsey, of massive sand, massive !o laminated clay, and interbedded 1987). The Bacons CastleFormation is the principal surficial and laminated fine sand, silt and clay, which are variable in deposit beneath the Norge uplands between tlre Broad Rock thickness and extenl The basal sand is composed principally (Johnson and Peebles, l98l) and Surry scarps; it is mappable of quartz, with lesser amounts of clay, heavy minerals, feld- over much of the Middle Coastal Plain in Virginia and North spar, some of which is kaolinized, and lithic fragments, Carolina (Colquhoun and others, in preparation). Part or all irrcluding chert and phosphate, and reworked glauconite. t2 VIRGIMA DIVISION OF MINERAL RESOURCES

This unit is commonly iron-stained and locally cemented by Oals and Coch (1973) also stated that the Windsor rests un- iron and manganese oxides. A belt of dominantly sandy conformably on the Moorings unit The sratigraphic and powhatan sediments follows the rend of upper Creek and morphologic relationships commonly observed near Surry Iong Hill Swamp. have been obscured on the York-James Peninsula; this was Sedimentary strucfires include flaser, wavy and causedby thearea'sproximity to theconfluenceof tle ances- lenticular bedding, clay drapes, flame structures, clay-pebble tral Yor* and James rivers and the subsequent dissection cross beds, desiccation cracks, and slump structures. Bed- during the Pleistocene Epoch. In the Norge quadrangle, ding is horizontal or dipping at less than l0; however, within ceriain massive, fine sand and sandy mud at elevations above laminated sediments it may dip as much as 25" due to.pene- 90 feet are similar to barrier and lagoonal facies of the contemporaneous slumping. Secondary features (fenicrete Moorings unit south of the James River. The relationship of andliesegang bands) arealsocommon. Sandy sedimentsare the fluvial-estuarine and bay members of the Windsor Fc- commonly yellow-brown to red whereas clay tends to be gray mation !o these sediments in the Norge quadrangle area is not to pink. lvlassively bedded or thick sections of unweathered as clear as the relationships are south of Surry where dissec- sand are gray. Soils are commonly pinkish-brown o dark red tion is less severe and morphology is a useful guide o the where the parent material is rich in clay and lightbrown over geology. sandy sediments. Soil profiles on the relatively undissected The Moorings unit in the Norge quadrangle is sub pleisocene Bacons Castle are thicker than over the younger divided into an @stern sand facies and a western clay facies. units. No shell fossils have been found but burrows of The sand facies is a massive, moderately well sorted, fine plant polycheates and decapods are common. fossils have sand and commonly lacks sedimentary structures. Locally, been recovered from the Bacons Castle near Richmond. gray clay laminations and drapes and clay-chip crossbeds Total thickness of the unit is about Z0 feet. Expo- have been observed. Color ranges from light gray !o light sures of the Bacons Castle Formation are found at Little yellow. The sand is quartzose with a few percent of opaque Creek Reservoir and in roadcuts in ttre uplands near Binns minerals. Ilall and Middle Plantation (now Fords Colony). The clay facies is composed of massively bedded The Bacons Castle Formation was deposited during sediments ranging from silty clay to muddy sand. Bionrba- a relative rise of sea level to about 170 feet inundating a tion is very common, but no diagnostic face fossil has been dissected coasal plain (Ramsey, 198?, 1988). Initially inter- obsenred. No other sedimentary structurcs have been found. tidal conditions similar !o those along the present Wadden Sediments are commonly gray to grayish-brown and soils are Sea, North Sea, or the Wash (Klein, 1977) predominated in generally light brown or gray. the paxt plain, easlern of the Middle Coastal but with the The Moorings unit formed as a barrier-beach (sand passage of time these were supplanted by marine or lagoonal facies) and backbanier lagoon or bay (clay facies) couplet. environments. The sand @arrier-beach) facies, which lies to the east of tlre The ageof theBacons Castle is uncertain because no clay facies, is at slightly higher elevations and grades larrally in sinr shell fossils or radiometrically dateable material have into the fine-grained sediments at lower elevations. Just as in been found" Based upon its sratigraphic position above the modem back-bay environments, the fine-grained sedimens late Pliocene Yorklown Formation and below the Windsor, are thoroughly bioturbated iC relatively advanced soil development, and the presence of The age of the Mmrings unit is considered kte plant fossils of Pliocene age near Richmond, the Bacons Pliocene or Early Pleisocene because the unit overlies the Castle is pliocene considered l-ate in age. Late Pliocene Bacons Castle and is, in [rn, overlain by the Windsor Formation of probable Early Pleistocene age. Both facies are each commonly less than l0 feet Moorings unit thick. Erosion has removed much of the complex; this pro duces a map paftern where older units are exposed on hilltops The Moorings unit was an informal stratigraphic and are surrounded by the Moorings on hillsides. Soil forma- unit proposed by Oaks and Coch (1973), to describe sand and tion and massivecolluviation of side slopes has obscuredthe silty problematic clay of stratigraphic relationship and age contacts; therefore, the locations of contacts are approximate westof the Surry scarp. This unit has been called the Sunder- and have been drawn !o conform with contour lines and land (Wennvorth, 1930) and the Elberon (Coch, 1965). Coch available field observations. (1965) proposed the Elberon formation and defined three facies: a silty clay facies Qagoonal) west of the scarp, a fine sand facies Oanier) along the scarp, and a silty sand facies PLEISTOCENE SERIES (nearshone marine) east of the Surry scarp. The eastern, silty sand facies was later redefined as the Windsor Formation Windsor Formation (Coch, 1968) and the remainder of the Elberon was infor- The Windsor Formation was named by Coch (1968) mally designated the Moorings unir (Oaks and Coch, 1973). for a sand, silt, and clay sequence which he considered o be PUBLICATION 87 13 lagoonal-estuarine in migin and had been assigned earlier o have been observed in these muddy sediments. Brown and the silty sand facies of theElberon (Coch, f965). Although red mouling is common and has been caused by root pene- the Windsor was originally mapped as the surficial formation tration and soil.forming processes. The Windsor in this area between the Surry and Suffolk scarps, it is now known to crop ranges in thickness from less than I foot to about 12 feeL out on the I-ackey plain along major rivers west of the Surry These sediments were probably deposited in a bay environ- scarp (Johnson and Peebles, 1984, and this report). The ment and have been mapped as'Qwb" in ttre Norge quad- formation was mapped as the Wicomico formation by Clark rangle. and Miller (1906, l9l2) and Wenrworrh (1930), and the The Windsor of this report correlates with that Kilby formation by Moore (1956). The Windsor Formation mapped by Bick and Coch (1969) south of the area around as mappedby Bick andCoch (1969), containsboth the Wind- State Road 612 (Longhill Road) in the Norge quadrangle. sor and the Charles City Formations of this report, as well as North of StateRoad6l2 theWindsorofBickandCoch (1969) part of the Moorings unir Some sediments presently mapped correlates with the Mmrings unit in this report Conacg as theWindsorFormation previously were included in the between the Windsor and other units are not easily di$cern- Bacons Castle Formation (Bick and Coch, 1969). The ible without numerous shallow borings. In areas of limited Windsor Formation is therefore amended in this report and is control, contacts have been generalized and drawn along more restricted in definition than previously reported. For conlour lines. this reason some contacts will not match between the Wil- Soils formed on the Windsor are comparable to soils liamsburg (Bick and Coch, 1969) and Norge (this report) formed on theBacons CastleFormation. Distinction benveen quadrangles. these two units is difficult with only shallow auger informa- Along the James and Chickahominy rivers the tion. An accurate determination of which formation is Windsor Formation consists of muddy, coarse sand and present cannot normally be made without examination of at gravel grading upward ino sandy mud. Exposures may be least the upper 15 feet of each unit The degree of weathering found in the sandpits at Five Forks and the R. T. Armistead pit as indicated by iron-oxide formation is grearer in the Windsor north of State Road 61 3 (Plate l). The lower part of this unit ttan in the younger Chuckanrck and Shirley Formations. is composed of muddy coarse-sand, pebbles, and cobbles. Where the Charles City is well-drained, the weathering pro- Rarely, boulders up !o 2 feet in diameter have been found. file is similar to the Windsor. The larger clasts are composed of quartzite and chert along With the exception of rare enigmatic burrows, no with lesser amounts of granite, phyllite, schist, gneiss, green- fossils have been found in the Windsor. The age of the stone, and other rock types common to the piedmont, Blue WindsorFormation is uncertain because no definitive fossils Ridge, and Valley and Ridge provinces of the Sate. Some or dateable material have been found. It is assigned an Early chert clasts contain fossils of Middle Ordovician and Lower Pleistocene'age because it overlies unconformably the Late Devonian age @.K. Rader, personal communication). Clay Pliocene Bacons Castle and older formations and is separated balls are also common. The sand fraction is dominantly from younger formations of Middle or late Pleistocene age quartz, but locally feldspar is very common. Sediment colors by a disconfumity. range from light brown (rare) o pinkish-brown. Trough cross-bedding is very common, with eastward dipping cross Charles City Formation stratification. The coarxe deposits atain a thicknass up to 25 feet The lower part of this unit is of fluvial origin and The Chades City Formation, herein named, is unconformably overlies the Yorktown and Bacons Castle comprised of an upward-fining sequence of gravelly sand and Formations. silty ro clayey sand. The type section is a gravel pit at the The lower coarse deposits grade upward into muddy Copeland riangulation station on the left bank of the James sand and sandy mud- The upper sediments are massively River in Charles City County, Virginia (Appendix I, Section bedded and, because ofbioturbation, are devoid ofany sedi- 2). The formation has been previously described as the mentary structures. Colors are gray, brown, and red; gray, Wicomico Formation (Wentworth, 1930). The Wieomico, red, and tan mouling are also common. Thickness ranges which was originally defined as a lerrace and later as a from less than 1 foot o about 25 feer These sediments are morphosratigraphic unit, is not apprqriately used as a interpreted !o be esnrarine in origin and commonly overlie the lithosratigraphic unit (Oaks and Coch, 1973). The Charle.s fluvial coarse-grained material. The fluvial-esurarine Wind- City, the surficial fmnration under the Grove pliain, is map sor is common along the James River west of the S urry scarp pable along the streams of the Middle Coasal Plain. The and tns been maped as "Qwf in the sUrdy area. formation has been extensively eroded; it is preserved as East ofthe Surry scarp, or east ofareas underlain by discontinuous remnants along the James and York riven and the Mmrings unit in the Williamsburg area, ttre Windsor their major ributaries. In the study area, the Charles City Formation is commonly massively bedded and is composed crops out along stream terraces in the Norge uplands and on of gray, clayey silt to silty clay or light-gray, silty fine-sand. the upland south of Cherry }Iall. Because of bionnbation, no primary sedimenary structures The formation is comprised of a lower interb€dded t4 VIRGIMA DIVISION OF MINERAL RESOURCES pebbly-sandandcoarse- and medium-grained sand, about 30 inches thick. Unlike the younger Shirley Formation, the feet thick, that grades upward into a fine sandy or clayey silt. clasts in the Chuckatuck are predominantly quartzose meta- Pebbles, cobbles, and boulden mark the basal contact or morphic and igneous rocks. The basal gravelly-sand grades occur sporadically in the lower part of the formation. These upward ino either a quartzose sand or into organic-rich sedi- coarse deposits are graded, lenticular in cross-section or form ments. Where the sand is the overlying unit, it is moderately thick planar beds, and are clast and matrix supported. The o well sorted, crossbedded to planar bedded with heavy- interstices in the clast-supported beds are filled with san4 mineral laminae accentuating the bedding, and lenticular in silt, and clay . The larger clasts are covered with a clay coating cross section. This unit ranges in thiclness from less than I and are commonly stained or cemented by iron and manga- foot !o more than I 1 feet in the deepest part of the paleochan- nese oxides. The coarser units are interbedded with planar- nels" A thin, gray clay is interbedded within the sand in bedded or crossbedded very-fine to coarse sand; Quarz is the places. t ocally the sand grades laterally into a pmrly sorted dominant mineral in these beds; feldspar (commonly kao- clay-sand or into organic-rich sediments. linized), heavy minerals, clay, and iron oxides are also pres- The organic-rich silt is highly variable in thickness ent. The beds are varied in color, being medium gray, light and ranges from less than 1 foot to more than 8 feer Grain size brown, and yellowish- and reddish-brown. Except for clay- and composition are also variable. The organic material lined bunows in the lower part, the formation is devoid of occurs as disseminated lenticular accumulations of woody fossils. The lower beds grade upward into, or have a sharp material, anddarkbrown toblackpeatbeds up to several feet contact with, the overlying beds. thick. The peat grades laterally into organic-rich sand or clay, The upper part of the formation ranges from a silty thinbedsof fine sand, G mayrestwith sharp contacton older fine-sand to a clayey silt. Bedding is commonly massive and deposits. The flora includes pines and a variety of deciduous the silt or sand is commonly light gray or brown. The rees and shrubs including hickory, sweet gum, and myrtle. uneroded upper surface of this formation exhibits aridge and On interfluves and parallel o the paleocoastline, the swale topography with a relief of about 5 feer. basal Chuckatuck contains a thin, discontinuous pebbly- or The age of the Charles City is unknown bur is cobbly-sand that grades upward into a gray, medium [,o fine, probably Early Pleistocene because it rests disconformably planar-bedded sand with heavy-mineral laminae. Locally the on the Windsor of presumed Early Pleistocene age and older sand contains Ophiomorp,fra burrows. The sand gades formations and is overlain by the Chuckatuck and Shirley upward into a silty fine-sand with an increasing amount of silt Formations of Middle Pleistocene age. The presence of clay and clay; this sandy unit is the most persistent lithology coatings on larger clasts, the higher degree of oxidation, and within the formation. Bedding is absentorrudimentary in the extensive ferricrete development within the formation indi- upper l0 feet of the unit. The maximum measured thickness cate that the Charles City is older ttran the Shirley. of the Chuckatuck on the ancient interfluves is 26 feet.In the Brandon area and near Shirley Plantation, the Chuckatuck is comprised of a basal, thin, gravelly sand, a light to medium Chuckatuck Formation gray, medium- to fine-sand, and an upper nonbedded silty clay or fine, sandy, clayey silt. The Chuckatuck Formation is formally named for The Chuckatuck can be distinguished from the sedimens exposed in the Smith pit" Isle of Wight County, Charles City Formation by its overall finer grain size, lack of Virginia (Appendix I, Secrion 4). The Chuckatuck in the feldspathic grains, shallower weathering profile, and its lower vicinity of the type section has been mapped as the Wicomico topographic position. In comparison to the Shirley, the (Wentworth, 1930), Windsor Formation (Coch, 1968; Oaks Chuckatuck is generally finer-grained, lacks the lithologi- and Coch, 1973) and the Chuckatuck Formation (Johnson cally immature clasts, and crops out at higher elevations. In and Peebles, 1986, 1987). This formation rypically exhibirs addition, channel-fill sequences havenotbeen found to be as an upward-fining sequence with a basal cobbly- to pebbly- thick in the Chuckafirck as documented in the Charles City on sand, overlying medium- to fine-sand, andacapping clayey Shirley Formations. sand or silt. Fluvial and marsh deposits occur locally in The age of the Chuclcatuck is uncertain. It is channels at the base of the formation; the overlying beds are unconformably overlain by the Shirley of Late Middle Pleis- bay or lagoonal sediments along the coast and estuarine along tocene age and in turn ress with an erosional disconformity the rivers. The Chuckatuck is the principal surficial unit on the Charles City and Windsor Formations of presumed under the Grafton flat (Johnson and Peebles, 1986, 1987). Early Pleistocene age. No definitive paleontologic material The fumation exhibits marked vertical and lateral lithologic has been found in the formation. The flora from the Chuck- variations. ahrck is indicative of temperate conditions at leastas warm as The lowermost beds of the Chuckatuck occupy the present. Shallow channels filled with coarse clasts and channels cut at least 25 feetdeep into older Pleistocene and organic-rich sediments at the base of the Chuckatuck indicate Tertiary sediments. The channel deposits commonly contain that the sediments were deposited on a dissected coastal plain pooly sorted, basal pebbly- to cobbly-sand that is less that 6 under fluvial and paludal regimes. When sea level rose and PUBLICATION 87 l5

water covered the interfluves, the upper Chuckahrck was leaves, and seeds were recovered from organic-rich lenses in deposited in tidally influenced bay and estuarine environ- the clays. Peat layen are sparse and occur as thin (l to 10 in) ments. beds within sands and clays and as lenticular masses m(re than 3.9 feet thick. The peat is composed of recognizable woody plant tissue and panially decayed organic material. Shirley Formation The sand fines upward in fte Shirley and occurs in thin to medium beds with multidirectional cross bedding or The ShirleyFormation is named herein for deposits cross laminations. Heavy-mineral laminae and clay drapes exposed in borrow pits of the Tarmac-LoneStar, Inc. plant at accentuate the cross stratification. The quartzose sand is Shirley Plantation in Charles City, Virginia (Appendix t, commonly graded, contains ripple marks, and is interbedded Section 3). This formation was formerly mapped as the with tlin, discontinuous sandy silt and clayey silt. The inter- clayey sand, sand and peat" and gravelly sand facies of the bedded silt and sand concains pencil-like, near vertical bur- Norfolk Formation (Cmh, I 965, I 968, I 97 I ; Oaks and Coch, rows but no other recognizable fossils. Although not ob- 1973; Johnson,1972, 1976: and Johnson and ottren, 1980) served in the study uea, Crassostrea irginica biostromes and as the Norfolk Formation west of the Suffolk scarp occurin quartzose andcalcareous silty sands atthebase of the (Mixon and others, 1982). The Norfolk Formation (Clark formation in the Fort Eustis area and Miller, 1906) as redefined by Oaks and Coch (1973) has The upper part of the Shirley Formation in the been shown by Peebles and others (1984) to consist of two Brandon and Norge area is comprised of thin o thick bedded, formations, the Tabb and an older unit, separated by a discon- clayey fine sand, clayey silt and less commonly silty clay. formity. The Shirley Formation is established in order to The bedding thickens upward and is obscured or destroyed by eliminate this stratigraphic problem, The Shirley Formation weathering in the upper part of the formation. The clay and is an upward-fining sequence, comprised of a basal, gravelly silt-rich beds are light to medium gray and are commonly sand that gpdes upward into a fine to coarse sand and is mottled reddish- or yellowish-brown. Thin sand beds within overlain by clayey silt or clayey, silty fine-sand. Coarse the lower part of this unit, are cross-laminated. Pebbles are maierial is also foundalong the Shirley stroreline (the Kingsmill scattcred sparingly through the fine gravel deposits and nod- scarp) where pebbles and cobbles were eroded from adjacent ules and near-vertical fernrginous tubes occur locally. The older deposits and along spits. The Shirley was deposited tubular structures may represent plant root and stem casts. underfluvial, estuarine, and marsh conditions in theBrandon The clay is principally composed of kaolinite, but also con- and Norge area but also includes barrier, bay, nearshore tains expandable minerals. When wet, the clays are plastic. marine, and aeolian deposits on the lower york-James pen- Perched water tables commonly form above the clay beds. insula and in southeastem Virginia south of the James River The Shirley ranges in thickness from less than 1 foot @eebles and others, 1984). near the Kingsmill scary to more than 55 feet in the paleo- The Shirley Formation exhibits lateral and vertical channels beneath the Huntington flat. Small terraces are lithologic and paleontologic variability" The basal Shirley found in minor drainages, for exainple, in Little Creek Res- deposits consist of a lower pebbly- to bouldery-sand. The ervoir @gure 6). coarse clastics, which reach a maximum thickness of 4.3 feet, are of variable lithology: quartz, sandstone, granite, gneiss, schist, chert, greenstone, diabase, and amphibolite. The cobbles and boulders are subangular to well rounded; the surfaces of the clasts are commonly faceted, reflecting joints, and bedding in the source rock. Above the basal gravelly sand are interbedded and intertonguing sand, clay, and peat bodies. The sands are medium gray to reddish-brown, thin to thick bedded, graded, planar or crossbedded, and commonly lenticular in shape. Souttreasterly dipping crossbeds prevail. The gravelly sands are locally cemented with iron and manganese oxides. Irnticular masses of clay and peat are interbedded with the sand in the lowerpart of the Shirley. The clay lenses, which range in thickness from I foot to more than 4.6 feet, are plastic, light gray to dark gray depending upon the amount of organic matter, and are thin- to medium-bedded. Finely divided, disseminated plantdetritus, and locally pyrite, impart Figure 6. Photograph of exposure of the unconformable a black color to the clays. In the Brandon quadrangle and at contact of the Shirley Formation overlying the Yorktown the type locality plant fragments, branches, small tree trunks, Formation; cross section B - B'.

16 VIRGIMA DIVISION OF MINERAL RESOURCES

Initially the Shirley in the Brandon andNorge area the bedding; the biologic affinity of these strucnres is un- was deposited under fluvial conditions in channels cut into known. The upper part of the Sedgefield and Lynnhaven is the underlying Aquia, Eastover, Yorklown, Windson, and comprised of thick beds of silty fine-sand and clayey silt. Charles City Formations. The upper potion is esnrarine in These deposits are qpically oxidized to a yellowish-brown origin. It is in urn overlain by ttre Tabb Formation and color and mottled reddish-brown. The Sedgefield and Holocene sedimenB. Uranium-series ages of 1&4,000 years Lynnhaven togetherrange in thickness from less than I fmt (Mixon and others, 1982) and 187,000 years (Cronin and near the Suffolk scarp to morc than 40 feet in borings in the others, l98l) on corals from apparently correlative deposits Dancing Point flat. along the Rapphannock River place the age of the Shirley A disconformity separates the Sedgefield and Formation as Late Middle Pleistocene. Lynnhaven Members from the underlying Shirley and older formations. The members are overlain by the Poquoson Member of the Tabb and Holocene-age marsh, swamp, Tabb Formation eshrarine, and alluvial deposits. Sedimens correlated with the Sedgefield Member on the York-James Peninsula and in The Tabb Formation (Johnson, 1976) crops out southeastem Virginia have been dated at 75,000 !o 120,000 along the Jame.s andChickahominy rivers and their ributar- years old (Mixon and othen, f982). The Sedgefield and ies within the shrdy area and on the Lower Coastal Plain of Lynnhaven Members were deposited by the ancesral James southeastern Virginia. The formation is subdivided into three River under fluvial-esnnrine conditions. members: the Sedgefield, Lynnhaven, and Poquoson. Al- though bay, barrier, and nearshore marine facies of these Poquason Member members havebeen mapped in the llampon, VirginiaBeach, and Suffolk areas (Johnson, 1976; Peebles, 1984), only the The Poquoson Member of the Tabb Formation fluvial-estuarine facies occur within the Brandon and Norge cmps out on tle Mulberry Island flat along the James and quadrangles. The Tabb has been mapped as the Talbot Chickahominy rivers. This member is composed of fine- !o formation (Wentworth, 1930) and as the Norfolk Formation coarse-sand and silt and is commonly upward-fining in grain @ick and Coch, 1969; Coch, 1971; and Johnson, 1972). size. The sediments are light gray under saturated conditions Because theboundary benveen the Sedgefield and Lynnhaven and light brown where oxidized. Bedding is rudimentary or members cannot be recognized in Brandon quadrangle, these lacking. This member is unfossiliferous and commonly less members are mapped together. The Sedgefield is notexposed than 9 feet thick. Holocene-age paludal and estuarine depos- in Norge quadrangle. its overlie the Poquoson. Sediments of the Poquoson were deposited during the Late Pleistocene by the ancestral James Sedgefield and Lynnlaven Members and Chickahominy estuaries.

The Sedgefield and Lynnhaven Members exhibit an upward-fining sequence of sediments interpreted to be flu- HOLOCENE SERIES vial-estuarine in origin. The lowermost part of this unit consists ofa light gray to light brown, cross-bedded pebbly Holocene deposits consist of estuarine, marsh, sand" Well-rounded cobbles are found locally at the uncon- swamp, and alluvial and colluvial sediments. These deposits formity between the Tabb and older formations. The clasts comprise a complex of estuarine sandy silts; paludal organic- are dominantly massive quartz, quartzite, and chert, but rich sand, silt, and poat, and fluvial gravelly sand, sand, and pebbles and small cobbles of granite, schist, and greenstone silt. The sediments are mutually intergadational and can be (?) are also known. The pebbly gravel has been partially traced downstream to lagoonal, bay, and nearshore marine cementod by iron and manganese oxides. The cross-stBtifi- deposits. The Holocene deposits disconformably overlay cation is accennnbd by the heavy-mineral laminae and ex- older formations. They are generally unconsolidated, and in hibits a prevalent southeasterly dip. Unis comprised of the case ofpaludal deposits, highly compressive. The Holo- organic-rich silty clay and peat up tro 14 feet thick occur in the cene deposits are subdivided into four lithofacies: 1) swamp lower part of ttris unit. peat (swamp sediments), 2) marsh silt (marsh sediments), The pebbly sand grades upward ino interbedded and 3) fluvial and beach gravelly sand (alluvium). A fourth light brown, fi ne to medium sand and light brown to medium lithofacies (subaqueous estuarine sandy silt), present under gray, very-fine sandy silr The sand and silt beds tend to water and periodically exposed at low tide was not mapped. decrease in thickness upward; they range in thickness from 2 Colluvial deposifs, which are commonly thin or crop out in feet to less than 0.4 inches. These beds are planar or cross- belts too narrow !o map, are not shown on the geologic map. stratified; the cross-stratification is multidirectional. Ripple The sandy-silt facies is subaerially exposed along and small-scale trough cross-stratification are found locally. the shore of the James River and is encountered in numerous Scattered bunows about 0.2 to 0.4 inches in diameter disrupt submarine borings along the James and Chickahominy riv- PUBLICATION 87 L7

ers. This facies ranges in texture from a fine sand near ments in this facies. Pebbles, cobbles, and small boulders beaches to a silty clay, but is typically a fine sandy silt. Quartz derived ftom older formations arie common in the basal part is the dominant mineral in the sand- and silt-sized fraction; of these deposits; sediments tend !o firrc upward and down- heavy minerals constitute less than I percent of the sedimenL stream. In the upper reaches of modern streams, this facies is Clay minerals, organic matler, and iron sulfides are common composed of silt and fine sand and rarely clay. Quartz is ttre in this facies. The deposits are thick bedded to laminated. dominant mineral alttrough heavy minerals are locally abun- The sediments are water-satuxated, compressive, unconsoli- dant in laminae. Disseminated organic-maBer is prevalent on dated, and at least45 feetthick along the ChickahominyRiver floodplains andin the shallow soils developedon this facies. and more than 100 feet thick beneath the Jame.s River. The The sand facies is commonly medium to thin bedded and facies grades downward into fluvial sand and laterally into commonly exhibits cross-sratification in the lowerpart The the paludal facies. This facies was deposited by the estuarine facies ranges in ttrickness from less than I foot to more than James River and its tributaries during the Holocene rise in sea 20 feet; in upland valleys, the sediments may occur as terraces level. Because of their subaqueous extent beneath the James along the major stream. Ttrc gravelly sand was deposited in and Chickahominy rivers, they are not shown on the geologic the channel of streams oralongbeaches during the Holocene maps. ard LatE PleisEocene. Swamp sediments, or $rc peat facies, underlies most Colluvial deposits occur as a veneer (less than 2.5 of the well-established swamps along theJames and Chicka- feet) on most slopes or as thicker deposits (geater than 11 hominy rivers and their ribuaries and is characterized by feet) along steep slopes or bluffs in the Brandon and Norge peat or uganic-rich silt and clay. Wood, woody plant quadrangles. The deposits are derived from older formations detritus, and seeds and leafs are a dominant constituent of the and obscure formational contacts. Mass wastage sedimens facies" Varying amounts of silt, clay, and fine sand are found vary widely in texture. They range from pebbly and cobbly disseminated or interbedded with the unit. Although organic sand, ifthey are derived from gravelly deposits ofthe Charles ma$er is dominant" small quantities of quartz, iron sulfide, City, S hirley, and Tabb Formations, to sand and clayey silt if and glpsum are found in the peat facies; locally, clay and silt they are derived from the weathered, fine-grained sediments constitute mse than 50 percent of the sediment. Bedding is of other formationsthe. Bedding is commonly absent but lacking to indistinct in the peat except where clay or silt locally stone lines and contorted bedding are found in these laminae occur. Recognizable plant remains include cypress, deposis. The color, which varies ftrom medium gray to black and sweet gum, and other hygrophilous species of trees. reddish brown, reflects the parent material from which the The deposit is commonly medium brown to black. The peat colluvium was derived and the local drainage conditions. The facies is more than 13 feet thick in the Brandon and Norge deposits were created by sheetwash, slumpage, and landslid- area and intergrades with the other Holocene lithofacies. The ing and are probably Holocene and Late Pleistocene in age. peat facies was deposited in swamps along streams and in the uplands during the very l-ate Pleistocene and Holocene epochs. GEOLOGIC HISTORY tl4arsh sediments, or the silt facies, is found beneath brackish and freshwater manhes along streams in the Bran- The Cmstal Plain sratigraphic sequence in the don and Norge quadrangles. Near ttre surface the organic Brandon and Norge area records the opening of ttre Atlantic content of this facies is high (greater than 20 percent) and de- Ocean during the Mesozoic era, the formation of the Salis- creases downward to a mineral-dominated sediment. Sand bury embayment and is partial filling with deltaic and asso- and silt-sized quartz is the principal constituents in the ciated sediments @otomac Group) during ttre Late Mesozoic mineral portion of ttre facies; clay minerals are the other era, and a succession of marine invasions during ttre Late major component of the sediment. Although the texture Mesozoic and Cenozoic eras. varies, the sediments range between a fine sandy silt and a Through the Tertiary, the Virginia Coastal Plain silty clay. Bedding is not well developed. Plant remains in was gently downwarped and faulted; the center of deposition the organic-rich portion of the facies include detritus of fresh shifted southward from Maryiand into Virginia (Newell and and brackish water plants, such as arow arum @eltandra Rader, 1982; Ward, 1984). Consequently, the shoreline virginica) and salt cordgrass (Spartina). The deposic are changed position and was reoriented (Jotrnson and others, compactible, water saturated, and commonly plastic. The 1985). Because only Upper Tertiary and Quaternary forma- deposis are at least 34 feet thick in places along the Chicka- tions areexposed atthe surface in the study area, only thelale hominy River. The sediments accumulated in fresh and Cenozoic history will be discussed in this report. Assuming brackish wa8er marshes during the Holocene. that the dates and correlations are correct, the following Alluvium, orthe fluvial sandfacies, crops outalong geologic hisory is postulated. upland streams and is encountered in the subsurface beneath The I-ate Cenozoic history of the Brandon and es$arine silts in theJames and Chickahominy rivers and their Norge quadrangles was punctuated by a series of marine tributaries. Gravelly sand and sand are the principal sedi- transgressions that spread across the entire Middle Coastal 18 VIRGINIADIVISIOIVIRGINIA DIVISION OF MINERAL RESOURCES

Plain duing the Iate Tertiary, and then by alternating sages lower Coastal Plain was exposed to subaerial erosion. The of valley cutting and filling along the ancestral James and valley of ttre ancestral James and Chickahominy riven was Chickahominy rivers through the Quaternary. During the cut downward, the former to below an elevation of 40 feet. IJte Miocene, a sea advanced across the study area to ttre Tributary streams extended their courses headward into the vicinity of Richmond, leaving a thin basal gravel as a result Norge uplands. I-ocal relief along the major rivers was ap- of shoreline erosion of older sediments and depositing the proximately 100 feer overlying fossiliferous sand of the up'per Eastover Formation. IVith the relative rise of sealevel to about95 feetin Withdrawal of the sea following deposition of the Easlover the Early Pleistocene, fluvial and marsh deposis (Windsor left the Middle Coasal Plain emergent and subject o sream Formation) were trappedin thevalley of theJamesRiverand erosion. its tributaries. When the interfluves were flooded by the A rise ofsea level during the Early Pliocene caused rising sea, a broad, open bay formed to the east of the snrdy flooding of at least the lower and Middle Coasal Plain. As area Shoreline erosion caused the strandline to rcreat to the the shoreline moved westward across the older marine and position of the Surry scarp. Concurrently, the James River fluvial deposits, a pebbly sand and overlying fossiliferous became tidat. At this stage the Windsor lagoon or bay ex- sand (Sunken Meadow Member) was deposited in relatively tended northeastward onto the Middle Peninsula and south- warm temperate seas. A regression of the sea in late Early westward into North Carolina and the James River estuary Pliocene time was accompanied by erosion of the newly reached westward to ttre Fall Zone. formed beds and a major extinction of marine bivalves (in- An Early Pleistocene reteat of the sea left the cludrng C he s ap e c t e n j efe r s o ni w andP la c op e c te n clinto ni us). Mddle and Lower Coastal Plain above water and subject o During the succeeding marine transgression in the Early Late erosion. The paleovalley of the James River was cut to near Pliocene, the Coastal Plain was faulted and warped. This present sea level in Charles City County during this episode caused the formation of a partially resnicted marine environ- of lower sea level. With the wastage of Early Pleistocene ice ment btween a barrier to the east and the fastland to the west; sheets, sea level rose. Stream gradients were reduced and C harna andother marine organisms flourished in the shallow, fluvial sediments were rapped in the paleochannel. Gradu- warm temperate to subropical, marine environment of the ally the tidal conditions replaced the unidirectional flow of study area. In the Late Pliocene the Middle Yorktown beds the earlier streams. Beach erosion along the ancestral James @ushmere - Morgarts Beach Members) wereexposedbriefly. andChickahominyriven and tlpirtributaries cuttheRuthville Subsequently, the biofragmental and shelly sands of the scarp. The aggradational surface of this transgression is the Upper Yorktown (Moore House Member) were deposited on Grove flat. the slowly deforming Coastal Plain during a Late Pliocene Following the deposition of the Charle.s CityForma- marine transgression across the area (Johnson and otfters, tion, sea level fell, then rose to a relative elevation ofapproxi- 1985). The seas withdrew from thearea following deposition mately 62feet when the Chuckatuck strata werc deposited, of the Yorktown strata. and then fell again during the early part of the Middle (?) Between the cessation of Yorktown deposition and Pleistocene. The floors of valleys were cut into the Chuck- the completion of the deposition of the lower Bacons Castle anrck and older formations o below present sea level. The Formation, more than 100 feet of the Yorktown and upper couse of the pre-Shirley paleochannel passed north of the EastoverFormations were sfippedaway in westem Charles uplands near Cherry Hall; the Chickahominy River held a City and eastern Henrico counties. This was accomplished parallel course to the James River on the east side of the primarily ttrough marine shoreline erosion of apre-existing Chickahominy State Wildlife Management Area. s8eam-dissected coastal plain. As the Bacons Castle shore- With the melting of glaciers in the Late Middle line migrated westward, a thin basal transgressive sand was Pleistocene, sealevel began torise, causing the paleovalley o deposited. The large supply of fine-grained sediments de- fill with fluvial and paludal sediments. When sea level rived from erosion of ttre fastland and from the ancestral reached its present level, the James changed from a fluvial to James River contributed to the formation of tidal-flat condi- an estuarine system with noticeable tidal effecs. A small spit tions over much of the study area. Tidal-flat deposits accreted developed along the north bank, southeast of Holdcroft; as sea level rose, but in the Late Pliocene a shallow restricted erosion by the Chickahominy and James rivers removed the sea or lagoon covered the Middle Coastal Plain to the Broad divide between the rivers. During the relative highsand at48 Rock scarp in the Richmond area. As the Middle and Lower feet, the James and Chickahominy rivers were confluent in Coastal Plain became emergent following deposition of the the vicinity of Mt. Airy and southeast of the Chickahominy Bacons Castle Formation, the James and Chickahominy riv- State Wildlife Management Arca. At this stage the estuarine ers extended their courses seaward. siltand clayof the upperShirley Formation were depositedon The Moorings unit was laid down in Iate Pliocene the Huntington flat and gravelly, coarse sand was laid down time as prt of a backbanier, barrier, and marine triplet; the locally along the shoreline. Growth of lllinoian Stage gla- latter has subsequently been removed by erosion. cien caused sea level to fall, exposing the Shirley Formation Prior to deposition of ttre Windsor Formation the and subjecting these and older deposis 0o erosion. PUBLICATION 87 19

The wastage of Illinoian glaciers resulted in the except the Yorktown and Eastover within the area of the inundation of the ancestral James River valley and its ribu- Brandon and Norge quadrangles. The first human utilization taries, and the deposition of the Tabb Formation. Subse- of clays in this areia was by the Indians who used the clay for quently, reduced gradients caused by the rise of sea level poftery (McCroy, personal communication). During the during the Early Sangamonian Stage dereased ttre compe- Colonial period, the clays were probably used for brick, tile, tency of the major streams in the Brandon and Norge artas and pottery. In most places the clays are very thin, contain and the lowermost beds of the Tabb Formations were depos- excessive amounts of coarse matorial, or have deleterious ited under fluvial conditions. With the continued increase in impurities, such as organic material. The most abundant and elevation of the sea, the James and Chickatrominy rivers widely used clay resoruces in the Brandon and Norge quad- became tidal and the upper estuarine silt, fine sand and clay rangles have been extracted from the upperpart of the Shirley of the Tabb Formation were deposited. Formation on the Huntington flat northwest of Bachelor During the Wisconsinan Stage, sea level fell to Point, off State Road 614 near Monis Creek, and south of approximalely 330 feetbelow present sea level and both ttre State Highway 5 in southwestern James City County. The James and Chickahominy rivers cut deeply into the older alumina-rich (AIOJ clays from the Shirley Formation are Pleistocene deposits, especially the Tabb Formation. The potentially suitable for roofing tile, building brick, and re- melting of the Wisconsinan glaciers caused flooding of the lated sructural uses (Johnson andTyrell, 1967; Sweet, 1982). Chesapeake Bay lowland and ia principal ributaries" With No active commercial pis exist in the area today. this inundation the James and the Chickahominy rivers Peat occurs sporadically in the Shirley Formation changed from a fluvial system to an esturine depositional and Holocene deposits. These deposits are uneconomical to mode. I"ocally fringing manhes developed on flats and along exploit because they are either oo thin and impure, not stream margins and migrated upward as sea level rose. geographically widespread, or are coveled by thick overbur- Shoreline erosion along the estuaries caused widening of the den. The fossiliferous Yorktown is locally near the surface rivers and confibuted to aggradation of the river bottoms. At and is potentially a source of lime and glauconite. Locally the present, sea level is rising at about I foot per century. mixture of lime and sand has been used for driveway fill; and the shell was burned for making mortar in the Colonial period. The mixture of weathered shell and glauconite ECONOMIC GEOLOGY wasused to enrich the soil for agricultural purposes. The economic potential for the extraction of both lime and glau- The principal economic resources exploited in the conite is limited by the low concentration of glauconite and Brandon and Norge quadrangles are sand and gravel and clay; the relatively deep burial of the resource. potentidly recoverable resources include peat and lime. Sand and gravel are mined from the lower part of the Shirley Formation at the Chickahominy Sand and Gravel Company ENVIROI{MENTAL GEOLOGY and previously at the American lvlaterials pits, and from small pirs in the Windsor Formation. Contiguous deposirs of the Geologic hazards in the Brandon and Norge quad- Tabb Formation are being mined in the Claremont quad- rangles include storm flooding, shoreline erosion, mass wast- rangle by the Chisman Company. The overburden of clayey age, land subsidence, and groundwater depletion and con- siltand fine sand is stripped and the sand and gravel are mined tamination. Sorm flooding is caused by intense short-term by dragline and front-end loader. The material is sold either rainfall and by storm-generated high tides. Rain-produced withoutbeneficiation or is sorted. The principal uses of the flooding occurs most commonly on the Huntington flat be- sandare as general fill material, cementand mortarsand, and cause infilration is impeded by the relatively thick and im- as subgrade material for highway construction. permeable clayey soils; runoffis inhibitedby the exception- Numerous small, intermittently active or abandoned ally low relief, widely spaced nahral drainageways, and sand gravel and pis are present in the fluvial-esnrarine facies dense vegetative cover. Much of the upland area subject o of the WindsorFormation on the Lackey plain, Bacons Castle flooding has been left in a forested state and the impact of Formation in the Norge uplands, and the Tabb Formation on flooding on humans has been minimized. Where farming and the Dancing Point flaL These deposits are not exploited ofter activities are practiced in the flood-prone areas, drain- extensively because the overburden is relatively thick, the age ditches have been constructed or field tile installed o deposis are sporadic in occurrence, or the sand and gravel remove the surface waler. con[ain undesirable impurities" They are used locally for Tidal flooding is limited o low-lying areas,princi- roadconstruction and general frll. The Windsor and some pally marshes (Moore, 1980), swamps, and narow stream- Bacons Castle deposits are well suited for road fill because bosoms less than 6.7 feet above sea level. For ttre most part there is commonly enough clay and silt to bind the coarser these areas are uninhabited, and roads, bridges, and other clasts. structures have been built above flood stage; consequently Clay-rich sediments are found in all fqmations the damage caused by tidal flooding in this area is minimal. 20 VIRGINIADIVISIO}VIRGINIA DIVISION OF MINERAL RESOURCES

Tidal flmding associated with major sorms is a contributing REFERENCES CITED facor in shoreline erosion. Shoreline erosion (Hobbs and others, 1975; Owen Akers, W. H., 1972, Planktqric Foraminifera and biosrratignphy of rcne Neogene forrnatiqrs northern Florida and Atlantic Coastal Plain: T[rlane and others, 1976) causes severe problems only locally. Bank Sudies in Geology and Palecrology, v. 9, n. 14,139 p. recession is most rapid where fetch is greatest (more than 2 miles), the coastline is underlain with noncohesive sand Berquist" C. R., and Ramsey, K W., 1985, The Barhamsville unit: an (lower part of the Shirley and Tabb Formations), beaches are intcrtidd to fluvial sequenoe between thc Yorkown and Windso( Forma- tianr, southeastenr Virginia [abc.]: American Arsociatioil of Peroleun narrow or lacking, and where the bluffs are low. Moderate Geologists Bulletin, v. 69, p. 1433. rates of erosion ( 1 . I to 2.4 feet per year) are reported along the Chickahominy River near Ferry Point and Monis Creek. The Bick, K. F., ard C.och, N. K, l%9, Geology of the Williamsburg, Hog Island, and Bacqrs Castle quadrangles, Virginia: Virginia Division of Old Neck Creek area which is surrounded by marshes, has Mineral Resources Report of Investigations 18, 28 p. been eroding about 4.5 feet per year in historic times (Owen and others, 1976) whereas accretion is occuning in the Clart,W.8., andMiller, B. L, 1906, Geologyofthe Virginia CoastalPlain, Oldfield area (Plate l). The high bluffs (greater than 66 feeg in The clay deposits of the Virginia Coastal Plain: Vrtgioia Ceological Survey Bulletin 2,p. ll-24. north of Trees Point are slumping because unconsolidated gravelly sand of the Charles City Formation is being undercut Clart, W. 8., and Miller, B. L., 1912, The physiography and geology of the by waves and sapped by groundwater. Shoreline protection Coastal Plain pror.ince of Virginia: Virginia Geological Survey Bulletin 4, devices, such as rip-rap, groins, and bulkheads, have been 22P. installed and have reduced or halted the recession of the Coch N. K., 1965, Post-Miocene stratigraphy rmd morpholory, inner shoreline caused by erosion and slumpage. Coastal Plain, southeastem Virginia: Office of Navd Research, Geography The dissolution of shell material in the upper York- Branch, Technical Report No. 6, 9l p. town Formation by groundwater has caused subsidence of the Coch, N. H., 1968, Geology of the Benns Church, Smithfidd, Windsor, and land surface. Small caverns and sinkholes,less than 8 feet in Chuckatuck quadrangles. Virginia: Virginia Divisiqr of Mineral Resources diameter, are lnown from sewer excavations near the inter- Report of Investigatians 17, zl0 p. section of StateRoad 614 and SettlersLane (Berquist) and in yards north of Williamsburg and in Norge (Johnson). Sink- Coch, N. H., 1971, Geolog5r of the Newport News South and Bowen Hill quadrangles, Virginia: Vttginia Divisiqr of Mineral Resdrrces Repct of holes, or dolines, some of which are seasonally flooded, occur Investigaticrs 28, 26 p. in open fields northeastof Lightfoot In addition, small-scale collapse structures were exposed during the excavation along Colquhoun, D. J., Johnson, G. H., Peebles, P. C., Huddleston, P., and Scoa, preparatio

ing, and increase the cost of constmction. Subsidence related Cooke, C. W., 1959, Cenozoic Echinoids of Eastem United States: U.S. to intensive groundwater withdrawals may also occur. Geological Sunrey Professional Paper 321, 106 p. The withdrawal of large quantities of groundwater Cronin,T. M., Szabo, B. J., Ager,T. A., Hazel,J.8,, andOwens,J. P., I98I, at West Point, Williamsburg, and Franklin from the York- Quatemary climates and sea levels of the U.S. Atlantic C.oastal Plain: town, Pamunkey, and Potomac aquifers Meng and llarsh, Scisrce, v. 2ll, no. 4/-79,p,2Y-2n. 1984) and production from the groundwat€r table aquifer have depleted groundwater supplies locally, necessitating the Dischinger, J. B., 1987, late lvlesozoic and Cenozoic stratigraphic and strucurral framework near Hqewell, Virginia: U.S. Geological Survey drilling of deeper wells. A concern of this water mining is the Bulletin 1567,48 p. possibility of depressrnization of the deeper aquifers, the encroachment of brackish water westward in the Norge quad- Flint R. F., 1940, Pleistocene feaures of the Atlantic Costel Plein: rangle, and possible subsidence. Other problems relating to American Jqrmal of Science, v. 238,p.757 -787 . groundwater in this area are the infiloation of leachate from Gardner, J. A., 1943, Mollusca frsn tlre Miocene and L,ower Pliocene landfills and septic system filtrer fields. The contamination of OfVirginia ana Norttr Carolina; Part l, Pelecypoda: U.S. Geological Suwey water supplies leaking wastes by sanitary from filter fields Professional Paper 199-A, p. l-17E. inlames City County has been reduced by improvements in water-well construction and by the installation of central Gardner, J. A., 1948, Mollusca frun the Miocene and Loner Pliocene of sewage treatment and water supply systems. Vlrgini" end North Carolina; Pan tr, Scaph@a and Gastropoda: U.S. Geological Survey hofessional Paper l9-B, p. l9-310.

Hack, J. T., 1955, Geolory of the Brandywine arca and origin of the ryland of southem Maryland: U.S. Geological Survey Professiunl Pa,pt 267'4, P. PUBLICATION 87 2l

Hazel, J. E., 1971. Ostracode bostratigraphy of the Yor*town Formation Johnsoq G. H., Goodwin, B. K., Ward, L W., and Ramsey, K. W., 1987b, (upperMiocene and lowerPliocene) of Virginia and North Carolina: U.S. Tertiary and Quaremary stratigraphy acnoss the Fsll7frie and westem Geological Survey Professional Paper7il, 13 p. Coastal Plain, southeastem Vrginia and North Carolina: Southeastem Sectian, Geological Society of America, 36th Annual Meeting,p, E7-144. Hobbs, C. W., Itr, An&rsqr, G. L., Pauon, M. A., ard Rosen, p., 1975, Shoreline sinradqr rcport Jarnes City, Virginir: Virginia Arstitute of Mafie Johnson, S. S., 1977, Gravitymapof Virginia: Virginia Division of Minerrl Science, SRAMSOE 8, 62 p. Resources, Simple Borguer map, l:500,00.

Jolmson, G. H., 1969, Gecflogy of the lower York-James Peninsula and Jolmson, S. S., gnd Tyrrcll, M. E., 196i1, Analysir of clay and rclated southbank of theJames Rivec Guidebookno. l, Departmentof Geologgr, msteriak-Eastern Cqrnties: Virginia Division of Mineral Resorcec Min- College of Williarn and Mary. 33 p. eral Resources Report 8,232p.

Jo,hnsur, G. H., 19?2" Gecilogy of the Yorktown, Poquoscr West, and Klein, G. deVries, 197, Clastic Tidal Facies: Continuing Educatim Poquoeon East quadrangles, Virginia: VttCi"i" Division of Mineral Re- Publishing Company, Champaign, Illinois, 149 p. sources Report of Investigations 30, 57 p. McGee, W. J., 1885, Geologic formations of Washington, D.C. and vicinity Jolmson" G. H., 1976, Geology of the Mulberry Island, Newpon News [abs.]: American Joumal of Science v. 31, p. {15474. North, and Hampton quadrangles, Virginir: Virginia Division of Mineral Resources Report of Investigations 41,72 p. McGee. W. J., 1888, Three formations of the Mddle Atlantic C.oastal slope: American Jqrmal of Science, 3rd. Series, v. 35,p. 12fr-466, Jolmsqr, G. H., and Peebles, P. C., 1981, Geology of the Capirol arca, Richmond, Virginia ir E{ine, J. D., Ear$ Science Field Guide, Region l: McGee. W. J., 1893, Cenozoic history d castem VlrSinil rnd Maryland, Virginia Depenment d EducEtiqr. Conunqrwealth of Virginia, p. 9-90. Geologicrl Society of America Bulletin, v. 5,p.24,

Johnsoq G. H., and Peebles, P. C., 1983, Ctastic-carbonate rclationships in Mansfield, W. C., 1943, Suatigraphy of the Miocene of Virginia end rhe Yorkown Formation (Early Pliocene) of southeastem Virginis [abs.]: Pliocene of North Crrolina. in Gardner, I. A., Mollusca from the Miocene Geological Society of America Abstracts wirh hograms, v. 15, n. 2, p. 107. and lowerPliocene of Virginia and North Carolina: U.S. Geological Suwey Professional Paper 199-A, p. l-18. Iohnson, G. H., and Feebles, P. C., l98d Stratigraphy of Late Pleisocene deposits between the Pamunkey and James riven, inner C.oasral plain, Mcl,ean,J. D., Jr., 1956,The Foraminifera of the Yorkown Formationinrhe Vtryinfu, in Ward, L W., and Knffr, Karhleen, eds., Stntigraphy and York-Jarnes Peninsula of Virginia, with notes on the associst€d mollusks: paleoologpr of fie orrcropping Tertiary beds in the pamunkey River Bulletin of American Paleontology, v. 36,p.85-394. rcgiat, centnl VtrCini" Coasral Plain--Guidebook for Atlantic Coastal Plain Geological Associaion 1984 field trip: Atlantic Coastal ptain Mcl,ean, J. D., Jr., 1957, The Ostracoda of the Yorlcown Formatim in rhe Geological Association, p. 79 -9 1. York- James Perrinsula of Virginia, nith notes qr dre collection made by Denise Mcrgin from lhe arca: Bulletin of American Paleurtology, v. 3E, p. Johnsoq G. H., urd Peebles, P. C., 19E5, The kre C.enozoic stratigraphy of 57-103. southcastem Virginir and the Dismal Swamp: American Association of Paroleum Geologists, Eastem Sectist Field Trip 4 Guidebook, 70 p. Mcl-ean,J. D.,Jr., 1966,Mocene and Pleisrocene Foranrini-fera rnd Ostra- coda d southeastem Virginir: Virginis Divisim of Mineral Resourses Iohnson, G. H., and Peebles, P. C., 1986, Quaternary geologic map of rhe Report oflnvestigaticrs 9, 123 p. Haueras 4" x @ quadrangle, Unied States: il Ridrmmd, G.M., Fullerton, Meng, A. A., Itr, and Hanh, J. F., 19E4, Hydmgeologic framework d the D.S., rnd Weide, D.L, eds., Quaremary Geological Arlas of rhe United VrCi"i" Coastal Plain: U.S. Gecilogical Survey Open-File Report E4-72E, States, U,S. Geological Survey Miscellaneous lvlap I-1420 (NJ-lS). 78 p.

Iolmson, G. H., and Peebles, P. C., 1987, Quatemary geologic map of rhe Mixm, R. B., and Newell, W. L., 1977, Stafford frult syslem: Srruchrres Chesqeake Bay T x 4o quadrangle, United States: h Richmqrd, G.M., documenting Cretaceous and Terriary deformation along rhe Fall Line in Fullerton. D.S., and Weide, D.L, eds., Quatemary Gecflogical Atlas of rhe northeastem Virginia: Geology, v. 5, p. 437 440. Uniad $ues, U.S. Geological Suwey Miscellaneous Map I-1420 (NI-18). Mixqr, R. B., Szabo, B, J., and Owens, J. P.. 19E2, Uraniunr-reries dating Jolmsoq G. H., Berquist, C. R., and Ramsey, K, 1980, Guidebok to the of mcillusks rnd corals, and age of Pleistocene deposits, Chesapeake Bay peninsula, [.ate C.enozoic Geology of the lower York-James Virginia: arcr, VLginiN and Maryland: U.S. Geological Survey hrofessicral Paper Guidebodc no. 2, Departnent of Geology, C,ollege of William and Mary, 52 1067-E,p. l-lE. P. Moore. K. A., 1980, James City Cornty tidal manh invcntory: Virginia p. Jolnson, G. H., Bequfut, C. R, Ransey, K, and Feebles, C., 1981. Institute of lvlarine Sciehce, SCRAMSOE Specid Report lE8, 100 p. Guidebod( !o the [.ere Cenozoic geolog5r of the lower york-Jrnes p€nin- sula, Virginia: Guidebook no. 3, Departrnent of Geology, Cdlege of Moorc, W. 8., 1956, Pleistocene terraces south of the Jamer River, Virginia: Willian and Mary,5E p. VttCi"i" Acrdemy of Scicnce Geology Section Guideboolq May 1956, 16 P. Johnson, G. H.. Peebles, P. C., Oae L J., and Snirh, B. J., 1985, The Late Cenozoic geology of sqrrheastem Virginia 8nd the Great Dismal Murray, G. E., 1961. Geology of the Atlantic and Gulf Cestal province of Swanp:American Asrociation of Petroleum Geologists Eastem Sectiqr, Nordr America: Harper and Brothen,692 p. Field trip I Guidebodc,68 p. Newell, W. L, ard Rader. E. K, 1982, Tectonic onrrol of cydical Iohnsoq G. H., Goodwiq B. K., End Ramscy, K, l9E7a" The "R" Streer sedimentatiqr in thc Chesapeake Group of Virginie ard It[aryland in Lyale, erposure: a rrarine srd fluviel sedimantary sequence rrcarthe Fall Zonc at P.T,, Centrd Appdachian Geolog5r, NE-SE Geologicd Society of America Riclunqrd, Va. [abc.]: Northeasam Sectioq Geologicd Sociery of Arner- Field Trip Guidebooks: Falls Church, Virginia, American Geological In*i- ica Absuircrs with Pr,ograms, v. 19,p2!2. ute. p. l-27. 22 VIRGINIADIVISIOIVIRGINIA DIVISION OF MINERAL RESOURCES

Oeks, R. Q., and Coch, N. K., 1973, Post-Miocene rrruigrrphy and APPENDIX I rnorphology, gqrtheastem Virginia: Vrryini. Divisiqr of Minenl Re- sourcas Bullain 82, 135 p. STRATIGRAPHIC SECTIONS Owen, D. W., Rogers, L. M., and Peoples, M. H., 1976, Shoreline situatiqr rcport, Charles City, VirginiE: Vr.gi"i. Insriurte of Marine Seience, Section 1: TVahrani Swamp SCRAMSOE Special Report ll5,56 p. The type section of the Barhamsville Memberof tlrc Peebles, P. C., 1984, l,ate Cenozoic landforms, strarigraphy md hisory of sea level oscillationg of soutlreastem Virgina and northeasrcm North Caro. Bacons Castle Formation is located along the norttr side of lina [PhD dissen]: College of Williun and Mary, Williamsburg . Virginir, State Road 632 beginning approximately 1200 feet east of ttre 149 p. intersection with Wahrani Swamp,New Kent County, Toano quadrangle, Additional discussion of this exposure may be Peebles, P. C., Johnsm, G. H., and Bcrquisr" C. R., 1984, The Middle and l,arc Pleistocene stratigrrphy of the outer coastal plain, sqttheasrcm Vir- found in Johnson and otlrcrs (1981). The elevation at the lop ginia: Virginia Minerals, v. 3O,n,2.p. l3-D. of the section is approximately 105 feet. The section was measured frorn the top of the hill downslope over a horizontal Ramsey, K., 1987, Gcologgr of tlre Bacons Csstle Formarion: Yor*-James Location, coordinates: Tnne 18, Peninsula, Viryinia [abr.l: Geological Society of Americr Abcrrscrr with distance of 280 feet. LITM Programs, v. 19, p. 125. 335,335 m.E., 4,147,200 mN.

Ramsey, K., 1988, Stratigraphy and sedimenology of a Lare Pliocene Thickruss intenidal to fluvial transgrcssive deposit: Bacons Casrle Formatim, Upper Yort-James Peninsula, Virginia [PhD dissert.]: Univenity of Delaware, Feet Newark, Delawarc,399 p. Bacons Castle Formation Barhamsville Member (31.5 feeO Roberts, J, K., 1932, The lower York-James Peninsula: Viryinia Geologi- cal Survey Bulletin 37,58 p. Clay, silt, and sand. Clay, light-gray; silt and sand, Rogen, W. B., 1884, A reprint of annual repons and other papen on the yellow-brown to pinkish red, very fine-grained; geology of the Virginias: New York, D. Appletcr and Co., 832 p. flaser-bedded;bedding dips up to 25" !o the north; burrows rare, bioturbation common, solution-collapse Sweet, P. C., 1982, Virginia clay material resources: Virginia Division of Mineral Resources, hrblication 36, 178 p. features present - I0-inch diameter vertical tube- shaped zone of disrupted and rotated blocks of Ward, L. W., 1984, Stratigraphy of outcropping Tertiary beds along rhe sedimenq faults, subvertical, intersecting, up to Pamunkey River--{entral Vnginir Coastal Plain in Ward, L W., and inch. Krafft, Kattrleen, eds., Stratigraphy and paleontology of the outcropping 6 feet exposed with offsets up to I At appro- Tertiary beds in the Pamunkey River region, central Virginia Coastal ximately 150 feet downhill the base of this section Plain---Guidebook for Atlantic Coastal Plain Geological Associatiqr 1984 coniains a penecontemporaneous slump block with field trip: Atlantic Coastal Plain Geological Associarion, p. ll-77,12pls, 4- o 6-inch interbeds of light-brown to brownish- pink gfay Ward, L W., and Blackweldeq B. W., 1975, Chesapecten. a new genus of silt and clay; clay displays convoluie Pectinidae (Mollusca: Bivalvia) frun the Mocene and Pliocene of eastem bedding and flame structures; base of the slump North America: U.S. Geological Suwey Professional Paper 861,39 p. is composed of rip-up clasts and clay pebbles; small subvertical faults with offsets up to 1 inch are assoc- Ward, L W., and Blackwclder,B. W., 1980, Strarigraphicrevisionof Upper Miocene and Lower Pliocene beds of the Chesapeake Group, Mddle iated with the slumping ...... 26.0 Atlantic Coastal Plain: U.S. Geological Survey Bullain 1,182-D, p. Dl- D6t. Clay and sand. Clay, gray to red, flaser to lenticular bedded; sand, yellow-brown to pink, very fine-grained; Wentworth, C. K., 1930, Sand and gravel resources of the Coastal Plain of Virginia: Virginia Geological Survey Bulletin 32. 146 p. burrows rare...... 5.5

Zet4 Isidore, Calver, J. L., Iohnson, S. S., and Kirby, J. R., lW, Aeromagnetic map of Virginia: U.S. Geological Survey Geophysical Yorktown Formation (upper 13.5 feeQ Investigations Map GP-9 16.

Sand, dark-brown, medium- to c@rse-grained, muddy; gades downward to silty clay, dark brown, massive to disrupted bedding, manganese or ferricret€ layer to 0.5 inch thick common; gxades downward to sandy clay, olive-gay with l/8 inch thick sand or clay laminations...... 4.5

Sand, light yellow, fine-grained, light-gray or black man- ganese stained sand marks the location of leached fossils PUBLICATIONSTIoN 67 23

(ghosts); liesegang rings, ferricrete laminations, biohr- beds; gray mud-lined vertical burrows, U8 to Ll4 inch in bated gray, clay flasers common in upper 5 feet...... 9.0 diameter, up to 4 inches long; ripple crossbedding at base defined by opaque minerals; sharp basal contacl...... 3.5 Section 2: Copeland Triangulation Station Sand and pebbles, quartz, light-brown; horizontally The type section of the Charles City Formation is bedded; gray clay balls and clay drapes up to 2 inches exposed in an inactive sand and gravel pit on the north bank thick...... "..6.0 of ttre James River, at the Copeland triangulation station, e:ut of WindmillPoint" Charles City County, Charles City quad- Sand, quartz, light-brown, medium- to coarse-grained; rangle. Elevation at the top of the section is approximately low angle trough crossbedding; pebbly sand interbeds; 65 feef l,ocation, UTM coordinates : Zone I 8, 3 16,350 m.E., dark brown liesegang scains; lower 5 feet of unit 4,131,300 m.N. augered...... 13.5

Thickrwss Sand, quartz, slightly feldspathic ftaolinite), fine- to Feet coarse-grained, light-brown to dark-gray; pebbly and cobbly, crossbedded, cross bedding accennnted by Chules Ciry Formation (65.1+ feet) heavy mineral laminae; cobble and boulder layer at base, basal contact sharp...... 6.8 Silt, clayey, light gray, weathers light brown, mas- sively bedded; gades downward !o a medium- to Sand, fine, silty, quartz, light-yellowish-brown, grades coarse-grained, sandy mud, pebbles rare in lower I downward o light gay; no apparent bedding, scattered fooq sharp basal contact commonly marked by thin heavy minerals, non-cohesive; base not reached by (1/a inch) ferricrere...... 11.0 au9er...... 7.8

Sand, muddy, light-brown, coarse-grained, quartz and feldspar with larger pebbles; clast supported; horizon- Section 3: Tarmac-LoneStar Pit, Shirley Plantation tally bedded; somewhat indurated by silt, clay, and iron oxide (limonite); sharp basal contact marked by 1 inch The type section of the Shirley Formation is de- thick ferricrete...... 1.5 scribed from the north-south face of the Tarmac-LoneStar borrow pit, 0.8 mile southwest of the intersection of State Sand, silty, brown to light brown, very fine-grained; Highways 5 and 156, Charles City County, Westover quad- long, low-angle rough crossbeds defined by l-inch rangle. The elevation at the lop of the section is approxi- thick beds of clayey silt (mud drapes) and massively mately 36 feet. Units in the pit exhibit lateral variation in bedded; small bunows common; grades to a basal 6- thickness and lithology. Location, UTM coordinates: Zone quartz inch-thick pebble bed; some manganese 18, 302,7 ffi m.8., 4, 133,870 m.N. staining...... 3.5 Thickness quartz, Sand, silty, light brown fine- to medium-grained Feet with interbeds of quartz pebbles defining trough cross- Shirley Fornwtion (25.7 ft) beds; small burrows common; ripple crossbeds defined by opaque minerals or manganese staining; lower 1 foot Silt, fine-grained sand, slightly clayey, few scattered, very coarse-grained, feldspar-rich sand with low-angle rounded pebbles, medium-brown, with roots and dis- trough crossbeds; sharp basal contacL...... 2.5 seminated organic matter, friable; grades downward to underlying unit...... 4.5 Sand, pebbles, and cobbles, quartz, light-brown, minor feldspar; horizontally bedded; clast supported; boulders Sand, fine-grained, clayey, silty; brown; quartzose, little inches to 1l in maximum diameter at base; sharp basal mica...... 2.4 contact...... 6.5 Sand, fine, silty, brown, interbedded with medium- o pebbly, quafiz, Sand, yellowish-brown, coarse-grained; coarse-grained, light-brown sand and clayey, silty, fine- becomes coarser downward; Eough crossbeds; sharp grained sand, interbeds are 0.2 to 0.9feet thick; coarser basal contacL ...... 2.5 sand beds, lenticular, pebbly and cobbly at base and fining upward, qwftzose with noticeable heavy minerals Sand, silty, quartz,light-brown; low-angle Eough cross- and mica; finer beds clayey, silty, with sca$ered pebbles 24 VIRGINIADIVISIOI\VIRGINIA DIVISION OF MINERAL RESOURCES up 0o 0.1 inch in diameter; clasts, predominately qrar?- ose; chert, schist, and granite clasts presentferricrete sporadic in lower part of this and subjacent unis...... 9.4 Sand, fine-grained with silt intefteds, coarsens down- ward, irregularly banded, Iight-gray, orange, and me- Sand, fine-grained, very clayey, silty, medium-gray, dium-brown, quarEose, micac@us, scatt€red clay lenses weakly cohesive, fines downward to cohesive clay, and very thin beds, soft, burrowed, grades through scattered fossil plant detritus consisting of seeds and several inches ino underlying unic...... 4.4 leaves of mk, beech, hickory, and pine, locally cut by gravel filled channels, lower contact sharp...... 6.3 Sand, fine-grained, generally coarsens downward, yel- lowish-brown to orange, medium-brown and light-gray, Sand and gravel, interbedded with pebbles and cobbles, quartzose, abundant heavy mineral; thin lenses and layers and boulders up to 6 feet in maximum diameter, coarse of pebbles, cross laminated and cross bedded, cross clasts common near base of beds and in channel-fills, stratification varies but commonly dips westward, dis- predominately quartzose clasS (sandstone, quartzile, rupted bedding, clay balls, near veftical and nodose clay- vein and foliated quartz, flint and chert), some granite, lined bunows, contact with underlying unit sharp...... 8.8 schist and greenstone; maximum thickness observed in pit is 8.6 feet; sharp basal contact ...... 3.1 Peat and organic-rich silt and sand, black to dark gray, interbedded white sand, abundant woody material, plant detritus, seeds and cones of pine, cn)ress, hickory, and Aquia Formatton (6.8 ft) other deciduous Eees, compacted, fetid odor, scattered pebbles in basd part ofunit; unit fills channels cut inlo Sand, silty, dark greenish-gray, quartzose and glauco- underlying formation...... 6.2 nitic with some mica; compact; nonfossiliferous except for indistinct molds; base not exposed...... 6.8 Sand, pebbly and cobbly, small boulders sparse, quartz- ose, clasts of quartzite, sandstone, chert, and granite, scatt€red clay clasts derived ftom underlying unit, planar- Section 4: Floyd Smith Sand and Gravel Pit shaped class parallel 0o bedding, cross bedded; deposit occupies base of channel or interfluves ..... 1.9 The tlpe section of the Chuckatuck Formation is exposed in the Floyd Smith Sand and Gravel Pit, 0.6 miles Charles City or Windsor Fonnation (1L.4 ft) west of State Highway 10 and 1.1 miles north of the City of Suffolk-Isle of Wight County line, in Isle of Wight County, Clay, silty, silt" and fine-grained sand interbedded, sand, Benns Church qudrangle. The Cat Ponds are immediately light-gray, orange, and reddish-brown, flaser bedded, south of the pit. Elevation of the undisturbed land surface lower part of unit medium bedded with sand predomin- varies from 55 io 60 feet. Unis in the pit exhibit lateral ant and upper paft thin to medium bedded with clay variations in thickness and lithology. I-ocation, UTM coordi- dominant, convoluted bedding, base of unit not nates: Zone 18,358,000 m.8.,4,084,450 m.N. exposed...... I1.4

Thicbuss Feet Holocene deposits Q.4 tr) APPENDIX II Clay, silty and sandy, organic-rich, dark-gray to black, abundant organic defitus and roots, plastic, wat€r satu- GEOLOGIC SUMMARIES OF SUBSURFACE DAT rated, lenticular, sharp basal contacl ...... 2,4 Explanation Chuclcatuck Forrnation (28.8 ft) W-1754 Numbers preceded by the letter "W" refer to Sand, fine, clayey, brownish-gray grading downward those wells or bcings whose samples are on file !o medium-brown, massive, non-bedded, roots com- in the Division's relnsitory. mon, grades into underlying unit...... 4.2 B-58A Numbers preceded by the letter "B" refer to those borings fumished by the Virginia Electic Silt, clayey, medium-gray to light-gray, lower part and Power Company. medium-brown, blocky, rudimentary bedding, contains m Top of marsh deposis more sand in lower 6 inches; gades into under- Qtp Top of Tabb Formation, Poquoson Member PUBLICATION 87 25

Qrl Top of Tabb Formation, Lynnhaven Member Elevation of Thickness Remarks Qs Top of Shirley Formation top (in feet) (in feet) Qwb Top of Windsor Fmmation (bay deposis) Qwf Top of Windsor Fcmation (fluvial-esnrarine w-3753 deposic) Qm 103 30 am Top of Mmrings unit Ty 73 r20 Tbc Top of Bacons Castle Formation Tc 47 100 Ty Top of Yorktown Formation Tn -147 30 driled Tc Top of Calvert Formation TD 280 Tn Top of Nanjemoy Formation Tm Top of Marlboro Clay w-3799 Ta Top of Aquia Formation Tbc l15 70 Kp Top of Potomac Group Ty 45 110 TD Total depth of well or boring in feet Tc -65 60 Tn -r25 80 All elevations are relative to a sea level datum. Tm -205 20 Ta -225 13 drilled TD 353

Elevation of Thickness Remarks w-3877 top (in feet) (in feeQ Tbc 88 40 Ty 48 110 w-1754 Tc -62 80 Qm 103 30 Tn -t42 70 Ty 73 r20 Tm -2r2 20 Tc 47 r00 Ta -232 78 drilled Tn -147 50 drilled TD 398 TD 3OO w-3977 Tbc r23 60 w-2192 Ty 63 130 Tbc 65 20 Tc -67 80 Ty 45 100 Tn -r47 70 Tc -55 100 Tm -2r7 30 Tn -155 70 drilled Ta -247 32 driUed TD2M TD4V2

w-6539 w-3259 Tbc 89 45 interbedded, Tbc 88 60 laminated sand and Ty 28 r20 cl@y Tc -92 70 Ty 44 17 brown-clay, sand Tn -162 5l driUed drilled and shell TD 301 TD 61

w-6540 w-3639 Tbc 100 55 laminated sand and Tbc 120 60 clay Ty 60 110 Ty 45 12 brown clay, sand Tc -50 90 drilled andshell Tn -140 80 TD67 Tm -22n 20 Ta -V40 40 w-6541 Kp -280 28 drilled Tbc r2,4 63 darkredfine TD428 sand,clay flasers

L 25 VIRGINIA DIVISION OF MINERAL RESOURCES

Elevation of Thickness Remarks Elevation of Thickness Remarks top (in feet) (in feet) op (in feet) (in fee$

Ty 6l & brown clay, sand w-6549 drilled and shell grading Tbc 100 39 laminated clay and down to dark gray drilled finesand clayey fine sand TD 39 TD IN w-6550 w-6s42 Tbc 80 27 red brown sand, Qtr ll 12 medium to fine clay laminations drilled sand Ty 53 8 brown sandy clay TD12 TD 35 drilled w-6543 w-6551 Qs 32 20 laminated clay, Qrl 16 24 silty sand grading organics down !o sand and Ty t2 7 sand and shell gravel TD27 drilled Qs -8 3 clay rD27 drilled w-6544 Qwb 95 6 yellow-brown fine w-6552 sand Qwf 68 16 clay grading down Qwf 89 1l clay and sand to coarse sand and Tbc 78 t4 laminated sand and gravel clay Ty 52 24 brown clay, sand Ty g l6 brown clay, sand drilled and shell drilled and shell TD 40 TD 47 w-6553 w-6545 Qwb 97 t2 gray sandy clay Qwf 81 24 clay grading down Tbc 85 19 dark red sand, to sand and gravel clay flasers Ty 57 13 brown clay, sand Tv6 2 dark brown clay drilled and shell TD 33 drilled TD 37 w-6554 w-6546 Qm 95 4 lightbrown sand Tbc 85 38 laminated sand and Tbc 9r 25 omnge sandy clay, drilled clay laminated TD 38 Ty 6 1 brown clay and drilled shell w-6547 TD 30 Tbc 70 26 brown sand, clay drilled laminations w-6555 TD26 Tbc r23 53 red-orange sand, drilled claylaminations w-6548 TD 53 Qs 33 48 laminated sand, drilled clay, organics w-6556 grading to muddy Qm l15 8 gray clay pebbly sand Tbc 107 37 onmge sand, clay TD 48 laminations Ty 70 3 green clayey silt drilled and shell TD 48 PUBLICATION 87 27

Elevation of Thickness Remarks Elevation of Thickness Remarks top (in fee$ (in feet) top (in feet) (in feet)

w-6557 w-6565 Tbc 95 35 interbeddedred- Qwb 90 10 gray clay over tan brown sand and sand clay Tbc 80 17 red brown sand, Ty 60 3 brown clay, sand clay laminations drilled and shell Ty 63 4 brown clay TD 38 TD 3T drilled

w-6558 w-6566 Qs v 37 silt grading down Qwb 97 7 brown silt grading to sand and gravel down to sand Ty -3 I shellandsand Tbc 90 30 red sand, clay TD 38 drilled drilled laminations r[l*37 w-6559 Tbc lot 42 red sandandclay 8.58A TD42 drilled m 2 35 black organic silt Qs? -33 2 sand and silty w-6560 drilled clay Tbc rvz 45 red sandandclay TD 37 Ty 57 2 brown clay and drilled shell B-60 TD47 m 2 5 organic sandy silt Qrp -3 6 finelocoarse w-6561 sand and gravel Tbc 75 28 brown silty sand, Elevation of Thickness Remarks clay laminations top (in feet) (in feet) Ty 47 2 clayey sand, shell TD 30 drilled Qs -9 4l clay grading down drilled to sand and gravel w-6562 TD 52 Tbc 80 35 red clayey sand, clay laminations B-70 Ty 45 12 brown clay, sand Tbc 95 5l rcd sand, clay drilled andshell laminations TD 47 Ty 4 32 brown clay, sand drilled andshell w-6563 TD 83 Qwb u 6 gray silty clay Tbc 78 22 red sand, clay B-80 laminations Tbc ll8 73 interbeddedsand. Ty 56 2 brown clay and and clay drilled sand Ty 45 9 brown sand, clay, TD 30 drilled andshell TD 82 w-6564 Tbc r23 40 interbeddedgray B-236 drilled and brown clayey Tbc 100 32 redfinesand, silt and sand drilled claylaminations TD40 TD32 28 VIRGINIA DIVISION OF MINERAL RESOURCES

Elevation of Thickness Remarks Elevation of Thickness Remarks top (in feet) (in feet) top (in feeQ (in fee$

B-237 inlo sand and Tbc lA 34 brownfinesand, clayey silt gray clay Te? 55 47 fossiliferous Ty 68 10 brown clayey sand drilled silty fine sand TDM drilled B-4 B-240 Tbc l2/1 50 interbeddedsand Qm 105 23 light gray fine and silty clay sand and clay Ty 74 22 fossiliferous fine Tbc 82 ll red fine sand, sand clay laminations Te 52 5 greenish-gray Ty 7I 3 brown clayey silt drilled glauconiticfine TD37 ddlled sand

B.AI B-5 Tbc 106 33 red fine sand, Qs 33 36 basalcoarsesand drilled claylaminations grades upward into TD 33 fine sand and clayey silt B.A4 Ty -3 14 micaceous clayey Tbc 85 18 siltandclay drilled silty fine sand Ty 68 55 clay, shell and Elevation of Thickness Remarks B-6 top (in feet) (in feet) Qs 56 upperclayey silt drilled sand grades downward TD 73 inoo sand and gravelly sand B-245 Te -14 10 micaceous clayey Tbc 97 43 silt and clay drilled silty fine sand TvY 29 brown clayey silt, drilled sand and shell TD72 B-7 Qtr ll basal pebbly sand B-l grades up ino Qs 36 interbedded sand sandy silt and gravel with Te -7 17 micaceous clayey upper part clayey drilled silty fine sand silt Te -12 9 silty fine sand ddlled

B-2 Qs 32 55 interbeddedsand and gravel wittr upper clayey silty fine sand Te -23 2 silty fine sand drilled

31 lower gravelly sand grades upward