U.S. DEPARTMENT OF THE INTERIOR Prepared in cooperation with the GEOLOGIC QUADRANGLE MAP U.S. GEOLOGICAL SURVEY MARYLAND GEOLOGICAL SURVEY BUCKEYSTOWN QUADRANGLE, MARYLAND AND VIRGINIA 77°30′ 77°22′30″ MAP GQ–1800 39°22′30″ 39°22′30″ S Qt _fl 21 80 85 E 77 CORRELATION OF MAP UNITS REFERENCES CITED A 54 _a 22 45 82 16 4 L 17 21 5 33 F E 1 2 1 1 2 1 82 Cenozoic surficial deposits E 20 4 4 V 6 8 0 8 2 2 0 6 15 _fa E _ 0 h 0 0 0 0 0 0 0 0 0 E Brezinski, D.K., 1992, Lithostratigraphy of the western Blue Ridge cover rocks in 0 T 0 0 0 0 0 0 0 0 0 L 85 81 73 34 _fr Qal 36 26 Holocene B Qal Maryland: Maryland Geological Survey Report of Investigations 55, 69 p. 16 25 Ogu 30 37 S 4 A 11 20 72 QUATERNARY 0 u 27 79 Holocene and 0 r Qt Burton, W.C., Froelich, A.J., Pomeroy, J.S., and Lee, K.Y., 1995, Geologic map of f Qc Qr Qt i f 40 c 27 e 26 25 84 _frs Pleistocene i e the Waterford and Virginia portion of the Point of Rocks quadrangles, Virginia: a 82 42 t l ^bs 11 QUATERNARY = 82 Pleistocene and d 1 29 71 22 QTt e U.S. Geological Survey Bulletin 2095, 30 p. 2 52 ^ Qc _fa late Tertiary AND TERTIARY p 61 2 62 o 81 _ b h 5 m s 74 Clark, F.W., 1924, The data of geochemistry: U.S. Geological Survey Bulletin 770, l Unconformity i O_gl 54 42 t e 71 79 69 s 70 Qal 72 t ^mt 22 e 10 841 p. n ^ 20 9 Qt Qal _ r Qal O gl 86 o 50 Early Jurassic JURASSIC s Jd m t 65 71 s Cloos, Ernst, and Cooke, C.W., 1953, Geologic map of Montgomery County and the s 10 u 45 _ t ^ frs h bl r 37 f 80 o a Intrusive contacts c w 60 District of Columbia: Baltimore, Maryland Department of Geology, Mines, and Wa- e ^mp 23 n 15 81 21 76 Culpeper basin ter Resources, scale 1:62,500. 61 51 80 Qr 77 81 54 Drake, A.A., Jr., and Lee, K.Y., 1989, Geologic map of the Vienna quadrangle, Fair- 12 52 29 11 78 43 55 51 ^bl Qc 17 39 F _a 65 76 _ar fax County, Virginia, and Montgomery County, Maryland: U.S. Geological Survey 25 22 70 ^bs ^tm Geologic Quadrangle Map GQ–1670, scale 1:24,000. ? _fr 61 32 Newark lower part of 25 Upper Triassic TRIASSIC 55 Supergroup Culpeper Group Drake, A.A., Jr., Sinha, A.K., Laird, Jo, and Guy, R.E., 1989, The Taconic orogen, ^ Qt 58 18 41 60 ^mp b 82 11 22 in Hatcher, R.D., Jr., Thomas, W.A., and Viele, G.W., eds., The Appalachian-Oua- s QTt _fr 45 15 60 77 41 ^mt ^mr chita orogen in the United States: Boulder, Colo., Geological Society of America, 23 51 17 _fl 40 50 80 The Geology of North America, v. F–2, p. 101–177. 62 61 35 Unconformity 85 72 _ 75 Jd Route 180 40 _ frs _frs 25 Edwards, Jonathan, 1986, Geologic map of the Union Bridge quadrangle, Carroll and 41 Ogu fr western Piedmont 43 67 71 42 57 Blue Ridge- Frederick Valley Sugarloaf Mountain Westminster Frederick Counties, Maryland: Baltimore, Maryland Geological Survey, scale 39 20 80 F 23 Qt South Mountain synclinorium anticlinorium terrane 1:24,000. 72 14 22 40 17 ^ 35 62 70 anticlinorium m Qc 15 ———1988, Geologic map of the Woodsboro quadrangle, Carroll and Frederick 9 _fl 25 81 37 p 67 Ogu Lower Ordovician ORDOVICIAN Counties, Maryland: Baltimore, Maryland Geological Survey, scale 1:24,000. ^ _fa 72 m 25 21 77 F 42 31 46 Lower Ordovician ORDOVICIAN Evans, N.H., and Milici, R.C., 1994, Stratigraphic relations and structural chaos on t 81 19 65 79 45 60 O_gl 42 66 81 75 _frs 82 and Upper Cambrian AND CAMBRIAN 52 37 the southeastern limb of the Blue Ridge anticlinorium and points east, central Vir- 22 Qt 52 80 86 43 _fl ginia Piedmont, in Schultz, Art, and Henika, Bill, eds., Fieldguides to southern Ap- 49 39 Qc ^mt 80 85 palachian structure, stratigraphy, and engineering geology: Virginia Tech Depart- 31 70 _fa Upper Cambrian Qr 39 63 82 ment of Geological Sciences Guidebook Number 10, p. 31–64. 62 28 O_gl 72 ^bl 62 _fr _frs Fauth, J.L., 1968, Geology of the Caledonia Park quadrangle area, South Mountain, _ 39 35 a 11 42 81 ? 75 Pennsylvania: Pennsylvania Geological Survey, 4th Series, Atlas 129a, 132 p. r Middle and ? _ar 53 79 _fr 75 _Zi Lower Cambrian Fisher, G.W., 1978, Geologic map of the New Windsor quadrangle, Carroll County, 62 _fl Maryland: U.S. Geological Survey Miscellaneous Investigations Series Map I–1037, 42 32 65 59 _t 80 scale 1:24,000. Qc ^ 47 59 Jd Tuscarora Creek bs 12 65 _fl _a Lower Cambrian CAMBRIAN ? Froelich, A.J., 1975, Bedrock map of Montgomery County, Maryland: U.S. Geologi- _frs Chilhowee Jd 42 Qt Group cal Survey Miscellaneous Investigations Series Map I–920–D, scale 1:62,500. 9 25 _h 40 79 Qal 33 Goddard, E.N., Trask, P.D., DeFord, R.K., Rove, R.N., Singewald, J.T., and Over- _ 60 57 80 40 _ul f 15 78 _ar _u r 37 45 85 Qal _uq beck, R.M., 1948, Rock-color chart: Washington, D.C., National Research Coun- 39 87 56 72 A 67 75 _ cil, 6 p. [reprinted by Geological Society of America, 1951, 1963, 1970]. ^ 33 55 ar _su mp 7 _fa 55 57 79 Lower Cambrian(?) Hopson, C.A., 1964, The crystalline rocks of Howard and Montgomery Counties, in 45 21 65 ^mt _sm 22 42 The geology of Howard and Montgomery Counties: Baltimore, Maryland Geologi- ^mp 21 Qt cal Survey, p. 27–215. _ Qr _fr 84 65 sl B 28 65 31 Horton, J.W., Jr., Drake, A.A., Jr., and Rankin, D.W., 1989, Tectonostratigraphic 17 _uq 27 Ogu 24 T _Zi Lower Cambrian(?) 17 71 L CAMBRIAN AND terranes and their Paleozoic boundaries in the central and southern Appalachians, 62 31 U and 11 _fa A LATE PROTEROZOIC in Dallmeyer, R.D., ed., Terranes in the Circum-Atlantic Paleozoic orogens: Geo- B&O Railroad 57 F _Zs Late Proterozoic(?) _ 25 11 59 _frs logical Society of America Special Paper 230, p. 213–245. f 59 85 Jd a ^mt 27 21 T S Hoy, R.B., and Schumacher, R.L., 1956, Fault in Paleozoic rocks near Frederick, U 22 T 23 Jd R L Maryland: Geological Society of America Bulletin, v. 67, no. 11, p. 1521–1528. Jd 25 75 H 37 U 70 T A 11 81 ? F Jonas, A.I., 1924, Pre-Cambrian rocks of the western Piedmont of Maryland: Geo- ? ^ bl 21 logical Society of America Bulletin, v. 35, no. 2 p. 355–363. Qr 22 17 C 70 I 30 New Design Road 10 Jd T 1 T ———1927, Geologic reconnaissance in the Piedmont of Virginia: Geological Soci- 32 R S A sl U 21 81 69 61 £ ety of America Bulletin, v. 38, no. 4, p. 837–846. 62 M 42 58 R 29 Ogu 57 10 H 80 T Jonas, A.I., and Stose, G.W., 1938a, Geologic map of Frederick County and adjacent _ 10 75 32 f Qc 77 73 Qt parts of Washington and Carroll Counties: Baltimore, Maryland Geological Survey, r 65 s ^bl 39 27 _uq Qr 62 21 70 72 37 IC DESCRIPTION OF MAP UNITS scale 1:62,500. 80 69 42 T Antietam Formation of Chilhowee Group (Lower Cambrian)—Light- R _a 10 _fr 78 ———1938b, New formation names used on the geologic map of Frederick County, 13 7 27 17 10 A [Color designations, in parentheses, are from Goddard and others (1948)] olive-gray (5 Y 6/1) to olive-gray (5 Y 4/1), medium- to coarse-grained, 19 65 10 M _ 12 46 52 _fr 71 60 u Maryland: Washington Academy of Sciences Journal, v. 28, no. 8, p. 345–348. _fr 81 _ 75 medium-bedded, locally ferruginous, micaceous, silty metasandstone in- Qt fa 35 _ 11 Keith, Arthur, 1894, Harpers Ferry Folio, Va.-Md.-W. Va.: U.S. Geological Survey F 70 R 78 CENOZOIC SURFICIAL DEPOSITS terbedded with very fine grained, silty metasandstone to sandy metasilt- f 23 Qal E 60 l D 59 11 Geologic Atlas of the United States, Folio 10, scale 1:125,000, 11 p. E 20 34 65 _ar 70 25 R 13 7 78 stone. Poorly exposed. Thickness estimated at 300 ft I ^bs 77 C 21 Alluvium (Holocene)—Unconsolidated mixture of clay, silt, sand, gravel, O Qal Keyes, C.R., 1890, Discovery of fossils in the limestones of Frederick County, Mary- K 35 53 _Zi V _ _fr 80 A 10 57 81 38 67 cobbles, and some boulders underlying flood plains of Potomac and Harpers Formation of Chilhowee Group (Lower Cambrian)—Brownish- L g 75 Jd _ land: Johns Hopkins University Circular 10, p. 32. L 28 h E Qt l Y Monocacy Rivers and their tributaries. Includes alluvial terraces as gray (5 YR 6/1) to dark-greenish-gray (5 G 4/1), silty, phyllitic metashale ———1891, A geological section across the Piedmont Plateau in Maryland: Geologi- S _ 81 Y 45 _frs N Ogu 69 80 f much as 10 ft above stream channels, and fine colluvial debris from ad- to highly sheared, phyllitic metasiltstone containing intervals of brownish- C ^ cal Society of America Bulletin, v.