Maryland Geological Survey Volume One Baltimore The

Home , Baltimore Gneiss, Georges Creek Valley, Seal of Maryland

GEOLOGICAL SURVEY

VOLUME ONE

BALTIMORE THE JOHNS HOPKINS PRESS 1897 ILLUSTRATIONS. PLATE FACING PAGE I. View of Model of the State of Maryland 23 II. The Potomae River Valley at Williamsport, on the Western Maryland Railroad 64 III. View of the Great Valley from Blue Mountain, on the Western Mary- land Railroad ; 104 IV. Map showing Atlas Sheets and Charts in Maryland 114 V. Map showing leading Triangnlation in Maryland 123 VI. Hypsometric Map of Maryland 142 VII. View showing Estuary of the Chesapeake Bay near Queenstown 146 VIII. The Falls of the Potomac 148 IX. View of the Youghiogheny Valley In the Alleghany Mountains, on the Baltimore and Ohio Railroad 152 X. The Gorge of the Potomac, at Harper's Ferry looking east, on the Bal- timore and Ohio Railroad 176 XI. Folded Strata of Lewistown Formation at Hancock, on the Baltimore and Ohio Railroad 182 XII. View of "Devil's Backbone" in Lewistown Formation north of Cum- berland, on the Baltimore and Ohio Railroad 186 XIII. Geological Map of Maryland 204 XIV. Isogonic Map of Maryland 404 XV. Instruments used in Magnetic Observations 450 XVI. Map showing the Preliminary Lines of Equal Magnetic Inclination and the Preliminary Lines of Equal Horizontal Force for Mary- land on January 1, 1897 4j93 XVII. Map showing the Lines of Equal Magnetic Declination for Maryland in the years 1700 and 1800 494 MARYLAND

GEOLOGICAL SURVEY

VOLUME TWO

BALTIMORE THE JOHNS HOPKINS PRESS 1898 ILLUSTRATIONS PLATE facing page I, The Potomac River near Cherry Run, at the Junction of the Balti- more and Ohio and Western Maryland Railroads 37 II. Lake Roland near Holllns Station, on the Northern Central Rail- way 33 III. Happy Valley near Port Deposit, on Pennsylvania Railroad System, 38 IV. Fig. 1.—Horizontal Beds 56 " 3.—Prominent " bedding " Joints in Granite 56 V. " 1.—Quarry showing Several Series of Joints 63 " 3.—Glacial Stripped Quarry 63 VI. Fragments of Cubes after Crushing 100 VII. Map showing the Distribution of the Granites, Gneisses, and Allied Rocks In Maryland 126 VIII. Foliated Granite. Port Deposit, Cecil County 130 IX. Fig. 1.—Photomicrograph of Granite, Port Deposit 138 " 3.—Photomicrograph of Granite, Ellicott City 138 X. McClanahan Granite Quarry, Port Deposit 143 XI. Granite-Porphyry. Ellicott City, Howard County 146 XII. Fig. 1.—Gaither's Quarry, Ellicott City 148 " 3 Weber's Quarry, Ellicott City 148 XIII. Granite. Waltersville, Baltimore County 150 XIV. Fig. 1.—Weller's Quarry, Granite 153 " 3.—Guilford and Waltersville Quarry, Granite 153 XV. Detailed View, Weller's Quarry, Granite 154 XVI. Fine-grained Granite. Guilford, Howard County 158 XVII. Fig. 1.—Photomicrograph of Granite, Granite 163 " 3—Photomicrograph of Gneiss, Baltimore 163 XVIII. " 1.—Curley-Schwind Quarry. Baltimore 166 " 3.—" Edmondson Avenue " Quarry. Baltimore 166 XIX. Map showing the Distribution of the Marbles in Maryland 170 XX. Beaver Dam Quarry. Cockeysville 174 XXI. Marble. Cockeysville, Baltimore County 178 XXII. Fig. 1.—Thirty-eight ton Monolith. Cockeysville 183 , " 2.—Potomac Marble Quarry, Point of Rocks 183 XXIII. Potomac Marble. Point of Rocks, Frederick County 188 XXIV. Fig. 1.—Whlteford Quarry. Cambria 193 " 2.—Slate Quarry. Ijamsville 193 XXV. Serpentine. Broad Creek, Harford County 196 XXVI. Map showing the Distribution of the Paleozoic Limestones in Maryland 198 XXVII. Red Sandstone. Seneca, Montgomery County 300 XXVIII. Fig. 1.—Sandstone Quarry, Emmitsburg 304 " 3.—Sandstone Quarry. Seneca 304 2 ] 8 ILLUSTRATIONS , pj^XE FACING PAGE XXIX. Fig. 1 Monocacy Aqueduct of White Quartzitc from Belt's Quarry, 308 " 3 Sandstone Quarry. Point of Rocks , 308 XXX. Map showing the Distribution of the Sandstones and Quartzites in Maryland 313 XXXI. Fig. 1.—Proctor Brothers' Quarry. Cambria 316 " 2.—" Peachbottom "-Excelsior-Peerless Quarry. Cambria.... 316 XXXII. " 1.—York and Peachbottom Quarry. Cambria 336 " 3.—York and Peachbottom Quarry. Cambria 336 XXXIII. Diagram of Control of the Frostburg Sheet 348 XXXIV. Diagram of Triangulation of the Frostburg Sheet 353 XXXV. Astronomical Transit and Zenith Telescope 358 XXXVI. Y-Level 368 XXXVII. Piedmont Plateau looking East from Rocky Ridge 376 XXXVIII. Fig. 1.—Heliotrope 386 " 2.—Traverse Plane-table Alidades 386 XXXIX. Eight-inch Theodolite 3H3 XL. Patapsco Valley from Woodstock College, on Baltimore and Ohio Railroad ?08 XLI. Johnson Plane-table 316 XLII. Telescopic Alidade 320 XLIII. Smith's Map, 1608 (reduced) 350 XLIV. Calvert Cliffs, on the Chesapeake Bay 356 XLV. Farrer's Map, 1651 364 XLVI. Herman's Map of Maryland (reduced) 378 XLVII. Bohemia River from Elk Neck at Head of Chesapeake Bay 384 XLVIII. Map showing Appalachian Topography by U. S. Geological Survey, 454

FIGURE PAGE 1. Ideal Figure showing Structures of the Earth's Crust (after U. S. G. S.).. . 48 2. Generalized Section from Sugar Loaf Mountain to North Mountain 4!) 3. Folded Rocks (after Van Hise) 51 4. Quarry in Horizontal Rocks .... 53 5. Diagram showing Relation between Thickness and Exposure in Beds 54 6. Section Across Western Maryland showing Restored Folds .... 59 7. Ingersoll-Sergeant Steam Drill. ^l 8. Ingersoll-Sergeant Quarry Bar Drill ^3 9. Wardwell Channelling Machine TS 10. Ingersoll-Sergeant Channelling Machine 74 11. Revolving Drum for Derrick 1'5 12. Lincoln Stone Planer 7® 13. Stone Polisher 14. Photomicrograph of Seneca Sandstone (magnified ten diameters) 97 15. Cube for Crushing Tests 113 16. Bar for Expansion Tests 115 17. Bar for Elasticity Tests 116 18. Bar for Sheaving Tests 117 19. Sketch Map of Peach Bottom Slate Area 321 30. Baldwin Base-Measuring Device -282 21. Signal 389 MARYLAND GEOLOGICAL SURVEY 19 FIGURE PAGE 22. Diagram 302 23. Diagram 304 24. Diagram 305 25. Douglas Odometer 335 26. Interior of Aneroid 33g 37. Ayllon's Map. 1527 340 28. Ribero's Map. 1529 344 29. The Lord Baltimore Map. 1635 (reduced) 361 30. Alsop's Map. 1666 3^6 31. Portion of Herman's Map, 1670, on original scale 377 32. The Griffith Map. 1794 (reduced) 399 33. Part of Alexander's Map of Southern Maryland 433 34. Section from a County Atlas hy Geo. W. Hopkins 443 MARYLAND

GEOLOGICAL SURVEY

VOLUME THREE

BALTIMORE THE JOHNS HOPKINS PRESS 1899 ILLUSTRATIONS PLATE FACING PAGE I. Stone Arch over Castleman Elver, Garrett County 39 II. Sample Road at Timonium Fair— Fig. 1.—Road Partially Constructed 43 Fljr. 3.—Road Nearly Completed 43 III. Map Showing the Physiographic Provinces of Maryland 56 IV. Map Showing the Divides and Drainage Basins of Maryland 64 V. Chart Showing Normal Annual Temperature and Precipitation for Maryland 72 VI. Map of the Road-Materials of Maryland 80 VII. Photomicrographs of Rock Sections— Fig. 1.—Trap Rock, Gabbro, Baltimore County 83 Fig. 2.—Trap Rock, Serpentine, Harford County 83 VIII. Photomicrographs of Rock Sections- Fig. 1.—Trap Rock, Diabase, Montgomery County 84 Fig. 2.—Gneiss, Baltimore County 84 IX. Photomicrographs of Rock Sections— Fig. 1.—Granite, Cecil County.. .. 88 Fig. 2.—Sandstone, Montgomery County 88 X. Photomicrographs of Rook Sections—- Fig. 1.—Marble, Baltimore County 96 Fig. 2.—Limestone, Washington County 96 XI. Photomicrographs of Rock Sections— Fig. 1.—Quartzite, Frederick County 104 Fig. 2.—Indurated Gravel, Prince George's County 104 XII. Three-Notch Road in St. Mary's County— Fig. 1.—View of Notches on Tree 130 Fig. 2.—View of Road with Notched Tree 130 XIII. Survivals of Early Road Methods— Fig. 1. —Breaking Stone by Hand, Frederick County 144 Fig. 2.—Hauling with Two-Wheel Ox-Cart, Port Tobacco, Charles County 144 XIV. Map Showing Through Routes of Travel before 1776 156 XV. Map Showing the Main Highways of Maryland 190 XVI. Types of Roads— Fig. 1 Dirt Road, Harford County 196 Fig. 2.—Limestone Road, Washington County 196 XVII. Types of Roads- Fig. 1.—Trap road, Baltimore County; Stone Spread in Layers and Rolled 200 Fig. 3.—Gneiss road, Baltimore City ; Stone Spread without Rolling. 300 20 ILLUSTRATIONS PLATE FACING PAGE XVIII. Types of Roads— Fig. 1 Gravel Road, Prince George's County 204 Fig. 3.—Shell Road, Baltimore County 304 XIX. Types of Bridges— Fig. 1.—Iron bridge over Choptank river, Caroline County 308 Fig. 3.—Stone bridge over Conocoeheague river, Washington County 308 XX. Maps of Allegany, Anne Arundel and Calvert Counties 316 XXI. Maps of Baltimore and Carroll Counties 330 XXII. Maps of Caroline, Cecil and Charles Counties 334 XXIII. Maps of Dorchester and Frederick Counties 333 XXIV. Maps of Garrett, Harford and Howard Counties 336 XXV. Maps of Kent, Montgomery and St. Mary's Counties 340 XXVI. Maps of Prince George's and Queen Anne's Counties 344 XXVII. Maps of Somerset, Talbot and Wicomlco Counties 348 XXVIII. Maps of Washington and Worcester Counties 354 XXIX. Testing Laboratory, Showing Deval Abrasion Machine 330 XXX. Testing Laboratory, Showing Page Cementation Machine 333 XXXI. Rock Fragments Before and After the Abrasion Test 334 Fig. 1.—Marble, Baltimore County 334 Fig. 3.—Limestone, Washington County 334 Fig. 3.—Trap Rock, Diabase, Frederick County 334 XXXII. Briquettes, Before and After Cementation Tests 336 Fig. 1.—Marble, Baltimore County 336 Fig. 3.—Limestone, Washington County 336 Fig. 3.—Limestone, Washington County 336 Fig. 4,—Trap Rock, Gabbro, Baltimore County 336 XXXIII. Types of Bad Roads in Maryland— Fig. 1.—Clay Road in Wet Weather, Howard County 400 Fig. 3.—Hillside Road with "Breakers," Harford County 400 XXXIV. Types of Bad Roads in Maryland— Fig. 1.—Sandy road, Worcester County 416 Fig. 3 Turnpike Abandoned from Rough Surface, Montgomery County 416 XXXV. Types of Bad Roads in Maryland— Fig. 1.—Dusty road, Baltimore County 433 Fig. 2 Undrained Road in Cut, Charles County 433 FIGURE PAGE 1. Mean Temperature in the Four Climatic Divisions of Maryland 66 3. Fluctuations in Normal Rainfall 73 3. Fluctuations in Annual Precipitation at Baltimore, 1871-1898 74 4. Old Sign-Board Giving the Rates of Toll on Animals and Vehicles 169 5. Showing Effect of Storm-Water on a Steep Grade (Vertical Scale Exag- gerated) 195 6. Cross-Section of I-Beam Bridge 306 7. Laying Side-Drain for Macadam Road on State Highway in Massachusetts. . 373 8. End Elevation and Longitudinal Section of a Pipe Culvert under an Em- bankment 373 9. Cross-Section of Road with Open Side-Ditches 374 MARYLAND GEOLOGICAL SURVEY 21 FIGURE PAGE J j' j. Sections of Lateral Drains for Underdrainage of a Road-bed 375 12. Pipe-Drain Badly Laid, and the Opening, as a Consequence, Partially Closed. 376 13. The Effect of Placing Broken Stone upon Firm and Soft Foundations, respectively 377 14. Applying Stone for Macadam Road on State Highway in Massachusetts 378 15. Rolling Surface of Macadam Road on State Highway in Massachusetts 381 16. Laying Telford Road on State Highway in Massachusetts 385 17. Roman Road 387 18. Early Eighteenth-Century Road 387 19. Late Eighteenth-Century Road 387 30. Modern Macadam Road 387 31. Section of Road on Sidehill with Side-Drain and Telford Foundation on Up- hill Side 388 33. Section of Road Cut Through Heavy or Soggy Soil with Telford Founda- tion and Side-Drains 388 38. Section of Old Shell Road Surfaced with a Thin Layer of Broken Stone.... 394 34. Road-Machine or Grader Refilling Earth over Pipe-Drain 303 25. One Form of Portable Stone-Crusher 304 36. Portable Form of Combined Crusher, Elevator and Screen 304 37. Rotary Stone-Crusher 305 38. Automatic Screen for Assorting Crushed Stone into Different Sizes 306 39. General Arrangement of Crushing-Plant on Sidehill Location 307 30. General Arrangement of Crushing-Plant on Level Ground 307 31. Reversible Horse-Roller 310 83. Steam Road-Roller 310 33. Gravel Road in Southwestern Connecticut 337 34. Macadam Road in Eastern Massachusetts 355 35. Sandy Road with Improved Gravel Road in Foreground, New Jersey 365 86. Macadam Road at Bryn Mawr, Pennsylvania 378 37. Six-Horse Load on a Main Road, Harford County .*. 406 38. Two-horse Load on a Macadam Road, North Caroliita 407 MARYLAND

GEOLOGICAL SURVEY

VOLUME FOUR

BALTIMORE THE JOHNS HOPKINS PRESS 1902 ILLUSTRATIONS. FACING PAGE. I. The City of Cumberland and the Narrows of Wills Mountain 28 II. View from Sideling Hill, looking east. From sketch by the author. 38 III. General View of arch of Oriskany sandstone on North Branch of the Potomac 84 IV. Detailed view of arch of Oriskany sandstone on North Branch of the Potomac 34 V. Theoretical map of the geography of the eastern United States in early Cambrian time 36 VI. View of the western slope of Wills Mountain in Wills Valley, near Cumberland, Md 54 VII. Theoretical map of the geography of the eastern United States during and at the close of the Devonian period 60 VIII. View of anticline in upper Silurian strata in cement quarry, Cum- berland, Md 82 IX. View of syncline in massive Devonian sandstone southwest of little Orleans, Md 82 X. Experimental demonstration of the development of anticlinal.... 84 XI. Drawing of the apparatus employed to compress models 84 XII. Theoretical sections based upon experimental results of folding... 86 XIII. Testing Machinery 110 Fig. 1.—Duval Machine for testing the wearing of road-materials. 110 " 2.—Brick Kattler for testing the wearing of paving-brick.... 110 XIV. Testing Machinery 116 Fig. 1—Old Page machine remodeled at the Laboratory of the High- way Division to make Impact tests on stone and paving-brick... 116 Fig. 2—Page-John son machine designed and made at the Laboratory of the Highway Division for testing the cementing value of stone dust 116 XV. Testing Machinery 122 Fig. 1. —Machine for testing the tensile strength of cements 132 Fig. 2.—Machine designed by the Highway Division for making cross-breaking tests of paving-bricks 122 XVI. Maryland Highways 134 Fig. 1.—Cut at Beaver Dam Hill on South River road, Anne Arundel County 134 Fig. 2.—Ruts formed in shell road near Salisbury, Wicomico County. 134 XVII. Belair-Churchville Road. 142 Fig. 1.—Before improvement 142 Fig. 2.—After improvement 143 12 ILLUSTRATIONS

PLATE. FACINO PAGE. XVIII Road Improvements 146 1.—Embankment made at loot of Belair Hill, Belair-Chureli- ville road, Harford County 140 Fig. 3.—Old and new location of Old Frederick near the Marriotts- ville road, Howard County 140 XIX. The Great Seal of Maryland, made in terra cotta by the Burns and Kussell Company 205 XX. I'ig- 1-—Showing method of mining down the dip 310 Fig. 3.—Passage of granite into residual clay Frenchtown, Cecil County 810 XXI. Clay bank showing carbonate of iron concretions, Reynold's old bank, Anne Arundel County 333 XXII. Eig. I.—Working a clay deposit as an open pit 354 Fig. 3.—Entrance to tire-clay mine on Savage Mountain 354 XXIII. Fig. 1.—Sand wheels 363 Fig. 3.— Eocene clay at Upper Marlboro, Prince George's County.. 363 XXIV. Fig. 1.—Troughing for kaolin-washing 370 Fig. 3.—Settling tanks at kaolin-washing plant 370 XXV. Fig. 1.—Ring-pit generally used in Maryland 314 Fig. 3.—Pallet racks for drying soft-mud building brick 314 XXVI. Fig. 1.—Drying-floor heated by flues underneath 338 Fig. 3.—Tunnel-dryer for drying brick 838 XXVII. Fig. 1.—Arrangement of brick in an updraft scove-kiln 330 Fig. 3.—Arch brick of a scove-kiln displaced during burning 330 XXVIII. Eig. 1.—Updraft continuous kiln showing dampers 330 Fig. 3.—Interior view of updraft continuous kiln 336 XXIX. Fig. 1.—Circular downdraft kiln for burning paving-brick 343 Fig. 3—Updraft kiln used for burning common brick 343 XXX. Forms of fire-brick made in Maryland 350 XXXI. Fig. 1.—Updraft kiln for burning fire-brick 350 Fig. 3.—Pan for grinding grog and tire-clay 356 XXXII. Views illustrating the process of turning jars 358 XXXIII. Forming cups on jig-wheel, Bennett's Pottery, Baltimore 363 XXXIV. View showing method of shaping ware by pressing 864 XXXV. Molding of sanitary ware, Bennett's Pottery, Baltimore 806 XXXVI. Dipping pottery into glaze mixture 370 XXXVII. Carrying saggers of ware into kiln for burning, D. F. Haynes & Son, Baltimore 373 XXXVIII. Decorating room, D. F. Haynes & Son, Chesapeake Pottery 374 XXXIX a& b Maps showing the distribution of the Potomac Group in Maryland. 378 XL. Map showing the location of the Topographic sheets of the U. S. Geological Survey made in cooperation with the Maryland Geologi- cal Survey 333 MARYLAND GEOLOGICAL SURVEY 13

PLATE. FACING PAOB. XL.I. Fig. 1.—Pleistocene clay, railroad cut north of Perryville, Cecil County 386 Fig. 2.—Clay beds of Pleistocene, Bodkin Point, Anne Arundel County 386 XLII. Fig. 1.—Pleistocene clays along shore south of Bodkin Point, Anne Arundel County 390 Fig. 2.—Buried forest overlain by Pleistocene clay, south of Bodkin Point 390 XLI1I. Fig. 1.—Patuxent river and works of New York Silicite Company, Caivert County 394 Fig. 2.—Nearer view of works 394 XLIV. Fig. 1.—Cliffs containing beds of Diatomaceous earth, Lyons Wharf, Caivert County 398 Fig. 2.—Diatomaceous earth-pit of New York Silicite Company, Lyons Wharf, Caivert County 398 XLV. Map of Central Cecil County showing areal distribution of clay- bearing formations of the Potomac group 406 XLVI. Fig. 1.—Patapsco "Fuller's earth" at Maulden Mountain 414 Fig. 2.—Patapsco clay in cut east of Principio Station, Cecil County. 414 XLVII. Map showing areal distribution of clay-bearing formations of the Potomac group in the region southwest of Baltimore City 422 XLVIII. Fig. 1.—Bank of blue Arundel clay, north of Curtis Bay Junction Baltimore County 430 Fig. 2.—Bank showing blue Arundel clay above and variegated Arundel clay below 430 XLIX. Fig. 1.—Variegated Arundel clay, Hertel's brick yard, Baltimore. .. 434 Fig. 2.—Bank of Arundel clay at Monumental, Baltimore County. 434 L. Panoramic view of Busey's brick yard, Baltimore. Bank of Arundel clay on the right, formerly worked for iron ore 436 LI. Fig. 1.—Arundel clays at yard 17, Baltimore Brick Company, Her- ing Run, Baltimore County 438 Fig. 2.—Arundel clay used for terra cotta, Washington road, Balti- more County 438 LII. Fig. 1.—Patuxent sand northwest of Curtis Bay Junction, Baltimore County 440 Fig. 2.—Patuxent sand capped by bed of paint-clay. Shell road, south of Baltimore 440 LIII. Fig. 1.—Patapsco stoneware clay, near Carpenter Point, Cecil County 446 Fig. 2.—Shale bed at Gannon's new cut, north of Westernport, Allegany County 446 LIV. Map showing the distribution of the Mount Savage fire-clay in Mary- land...... 450 14 ILLUSTRATIONS

rLATE. FACING PAGB. LV. Fig. 1.—General view of works of Queen City Brick and Tile Com- pany, Cumberland, AUegany County 454 Fig. 3.—Portion of shale bank of Queen City Brick and Tile Com- pany, Cumberland, Allegany County 454 LVI. Fig. 1.—Pit of Maryland Clay Company, Cecil County 456 Fig. 3.—Kaolin outcrop in Sutton's cut, northeast of Perryville, Cecil County 456 LVII. Maryland Clay Company's washing plant at Northeast, Cecil County 458 Fig. 2.—Residual fire-clay, J. Smith's pit, Dorsey, Howard County. 458 LVIII. Map of central Maryland showing the rocks yielding residual clays. 463 LIX. Fig. 1—General view of Conococheague Brick and Tile Company's Works, Williamsport, Washington County 466 Fig. 3.—Pit of Washington Hydraulic-Press Brick Company, Har- man, Anne Arundel County 466 LX. Fig. 1.—The Burns and Russell Company's Terra Cotta Works, Baltimore 468 Fig. 3.—Molding Room, The Burns and Russell Company's Terra Cotta Works 468 LXI. Baltimore Terra Cotta Works 470 LXII. Maryland Penitentiary showing roof covered with Maryland Roof- ing tile 472 LXIII. Fig. 1.—Kiln shed. Union Mining Company, Mount Savage 474 Fig. 3—Heaps of clay weathering at mines of Savage Mountain Fire Brick Works 474 LXIV. Fig. 1.—Molding department. Union Mining Company, Mount Savage 476 Fig. 3. —Molding fire-brick 476 LXV. Fig. 1—Molds for gas-retorts, Baltimore Retort and Fire Brick Co. 478 Fig. 3—Retorts placed in kiln for burning 478 LXVI. Fig. 1.—Kiln, Baltimore Retort and Fire Brick Company 480 Fig. 3.—Interior of kiln of flre-brick, same works 480 LXVII. Fig. 1 Molding enameled-bricks. Mount Savage 482 Fig. 3.—Drying room of Enameled-Brick Works, Mount Savage... 482 LXVIII. Cones of Maryland clays from different localities which have been heated to cone 27 (3038° Fahr.) in the Deville furnace 484 LXIX. Fig. 1.—Chesapeake Pottery Works, D. F. Haynes& Son, Baltimore. 486 Fig. 3—Maryland Pottery Works, Edwin Bennett Company, Balti- more 486

FIGURE. PAGB. 1. Generalized profile, showing relative areas of the earth's surface at different heights and depths 85 3. Curves showing rate of wear for different paving brick during rattler test. 112 MARYLAND GEOLOGICAL SURVEY 15

FIGURE. PAGE. 3. Curves showing rate of wear for soft and hard rock during the abrasion test 126 4. Sketch of the hall-mill for making stone dust for the cementation test of macadam materials 130 5. Microscopic section showing clay particles in ball-clay from Edgar, Fla.... 249 6. Microscopic section showing fine silt particles in hall-clay from Edgar, Fla. 350 7. Microscopic section showing uneven surfaces of clay particles 351 8. Microscopic section showing particles in a lean clay 353 9. Segar cones before and after testing 356 10. The " Johnson" square center-feed open delivery filter-press 374 11. Press used for compacting washed kaolin 375 13. Raymond pulverizer and separator for cleaning clays 377 13. Machine used for testing the tensile strength of clays 380 14. Fletcher furnace used for testing clay samples 383 15. Sectional view of Segar Furnace used in testing clay samples 383 16. Section of Deville Furnace used in testing clay samples 283 17. Sectional cut of Sturtevant roll jaw crusher 311 18. Dry-pan used for pulverizing shales and clays 31S 19. Steadman disintegrator for breaking up lumpy clay 318 30. Disintegrating rolls for grinding clay 314 21. Pug-mill used for tempering clay 316 ■22. Martin soft-mud machine for molding brick 318 23. Plan of a soft-mud brick plant 319 34. Stiff-mud machine for molding brick 321 35. Side out, automatic cutter 333 86. Section of Simpson dry-press brick machine 333 27. Boyd dry-press brick machine 324 38. Eagle repressing machine 326 29. Vertical section of Grath coking furnace 333 30. Ground-plan of Grath coking furnace 334 31. Section of Haigh continuous kiln 335 32. Horizontal plan of Haigh continuous kiln 336 33. Press for making roofing tile 346 34. Pipe press used in pressing sewer pipe 349 MARYLAND

GEOLOGICAL SURVEY

VOLUME FIVE

BALTIMORE THE JOHNS HOPKINS PRESS 1905 ILLUSTRATIONS pLATE FACING PAGE I. Eight-Inch Theodolite 25 II. Map of Lines of Equal Magnetic Declination for Maryland 44 III. Map of Equal Magnetic Declination for Gaithersburg 44 IV. Map of Lines of Equal Magnetic Inclination for Maryland 64 V. Map of Lines of Equal Horizontal Intensity 90 VI. Fig. 1.—Mound on Mason and Dixon Line 112 Fig. 2.—Mound on National Road 112 VII. Map of Boundary Line between Allegany and Garrett Counties. 120 VIII. Fig. 1.—Confluence of Savage River and North Branch of the Potomac 128 Fig. 2.—Triangulation Station (MO 128 IX. Fig. 1.—Eastern Avenue, Baltimore County, Macadam Road with Trap-rock Top and Slag Foundation 166 Fig. 2.—Rising Sun-Farmington Road, Cecil County, Macadam Road, all Courses made of Trap-rock 166 X. Fig. 1.—Belair-Churchville Road, Harford County, Finishing a Macadam Road I?* Fig. 2.—Chestertown-Centerville Road, Queen Anne's County.. 174 XI. Roads Built under Plans of Maryland Geological Survey 182 Fig. 1.—T B Road, Prince George's County, Deep Cut made to Reduce the Grade of Wilson's Hill 182 Fig. 2.—T B Road, Prince George's County, Concrete Culvert and Embankment at the Foot of Wilson's Hill 182 XII. Hydraulic Cement Testing Machine • 198 Fig. 1.—Machine with Cement Ring in Position ready for a Test 1®8 pig. 2.—Machine after a Test with the Top Cap removed 198 XIII. Map showing the Distribution of Coal Measures of Maryland.. 221 XIV. Map showing the Distribution of the Coal Fields of the United States 230 XV. Map showing the Northern Appalachian Coal Field 238 XVI. Views of Pottsville Formation 244 pig 1.—Lower Sharon Coal and Sandstone, near Western- port, Allegany County. Fig. 2.—Upper Connoquenessing Sandstone, Swallow Falls, Garrett County. ^ ILLUSTRATIONS

PI'ATE FACING PAGE XVII. Views of Allegheny Formation 250 Fig. 1.—Clarion Sandstone, near Windom, Garrett County. Fig. 2.—Lower Kittanning Coal and Sandstone, near Barnum, W. Va., Garrett County. XVIII. Views of Conemaugh Formation 254 Fig. 1.—Franklin Coal, near Lonaconlng, Allegany County. Fig. 2.—Morgantown Sandstone, near Lonaconing, Allegany County. XIX. Views of Monongahela Formation 256 fig- 1.—Knob with Bench at Pottsville Seam Horizon, one mile south of Barnum, W. Va., Garrett County. Fig. 2.—View of " Big Vein " Coal in Ocean Mine No 3. XX. Views of Monongahela and Dunkard Formations 258 Fig. 1.—Outcrop of Pittsburg Seam, near Lonaconing, Alle- gany County. Fig. 2.—Dunkard Slope, near Frostburg, Allegany County. XXI. Views of Maryland Mining Towns 322 Fig. 1.—Frostburg. Fig. 2.—Lonaconing. XXII. Views of Mining Plants 326 Fig. 1.—Consolidation Coal Company, Ocean No. 1. Fig. 2.—Consolidation Coal Company, Pumping Shaft. XXIII. Views of Coal Mining Plants 330 Fig. 1.—Consolidation Coal Company, Ocean No. 3. Fig. 2.—Consolidation Coal Company, Ocean No. 7. XXIV. Map showing the Distribution of the Lower Kittanning Coal... 334 XXV. Views of Coal Mining Plants 338 Fig. 1.—Black, Sheridan and Wilson, Union No. 1. Fig. 2.—Black, Sheridan and Wilson, Carlos. XXVI. Map showing the Distribution of the Upper Freeport Coal 342 XXVII. Views of Coal Mining Plants 346 Pig. 1.—Georges Creek Coal and Iron Company, Gilmor. Pig- 2.—Georges Creek Coal and Iron Company, Gilmor. XXVIII. Views of Coal Mining Plants 354 Fig. 1.—New Central Coal Company, Koontz. Pig. 2.—American Coal Company, Jackson No. 5. XXIX. Map showing the Distribution of the Bakerstown Coal 362 XXX. Views of Coal Mining Plant 370 Fig. 1.—Piedmont Mining Company, Moscow. Pig. 2.—Maryland Coal Company, Appleton. XXXI. Views of Coal Mining Plants 373 Fig. 1.—Davis Coal and Coke Company, Henry No. 7. Fig. 2.—Davis Coal and Coke Company, Henry. MARYLAND GEOLOGICAL SURVEY 15 PLATE FACING PAGE XXXII. Map of Georges Creek Coal Basin, showing the location of Mining Properties and the Areal Extent of the Pittsburg ("Big Vein") and Lower Coals... 386 XXXIII. Views of Coal Mining Plants 394 Fig. 1.—Piedmont and Georges Creek Coal Company, Wash- ington No. 1. Pig. 2.—Braddock Mining Company. XXXIV. Map showing the Distribution of the Upper Sewickley Coal 402 XXXV. Map showing the Distribution of the Waynesburg Coal 406

FIGURE PAGE 1. Diurnal Variation of the Magnetic Declination at Washington, D. C. (1888-1890) 70 2. Diurnal Variation of the Magnetic Inclination at Washington, D. C. (1889-1890) 71 3. Diurnal Variation of Curve of Declination and Inclination at Wash- ington, D C. (1889-1890) 71 4. Diurnal Variation of the Horizontal Intensity at Washington, D. C. (1889-1890) 82 5. Diurnal Variation of the Vertical Intensity at Washington, D. C. (1890) 83 6. Diurnal Variation of the Total Intensity at Washington, D. C. (1890). 83 7. Triangulation Stations of U. S. Geological Survey Ill 8. Diagram showing effect of Convergence of True and Magnetic Me- ridians 113 9. Triangulation Connecting Terminal Points of Boundary Line 115 10. Profile of Boundary Line 118 11. Secondary Triangulation at Mouth of Savage River 119 12. Sketch showing Triangulation at Mouth of Savage River 123 13. Profile of Line of Levels across the Top of Big Savage Mountain 127 14. Typical Cross-section of Eastern Avenue, Baltimore County, showing Macadam Construction with Slag Foundation and Trap-rock Top Course 167 15. Results of 15 Rattler Tests of Soft Brick, showing per cent of wear.. 193 16. Results of 15 Rattler Tests of Hard Brick, showing per cent of wear. 193 17. Sketch showing plan. Half Section and Half Elevation of Mould for making Cement Rings used to Determine the Tensile Strength of Cements 198 18. Sketch showing Half Section and Half Elevation of Machine for making Wearing Tests of Stone and Brick 201 19. Section showing Relative Positions of Prominent Beds in Maryland Coal Measures 243 10 ILLUSTRATIONS FIGURE PAGE 20. Map showing Anticlines and Synciines of Coal District 260 21. Columnar Sections of Pottsville Formation 293 22. Columnar Sections of Allegheny Formation 297 23. Columnar Sections of Conemaugh Formation 301 24. Columnar Sections of Monongehela Formation 309 25. Columnar Sections of Dunkard Formation 313 2G. Map showing Location of Coal Basins in Maryland 318 27. Generalized Section showing Vertical Position of Coal Seams 319 28. Diagram showing a Section of the Workings of the " Big Vein " for Mine No. 1, Georges Creek Coal and Iron Company 532 29. Coal-cutting Machine, called by the Miners " A Punching Machine ".. 540 30. Sketch illustrating the usual Arrangement of Tracks, Props, and Cross-bars in Rooms 544 31. Sketch showing Relations of Overcast and Intake Airways 547 32. Sketch of Miner's Lamp used in Georges Creek Basin 549 33. Sketch showing Form of Tipple commonly employed in Georges Creek Region 553 34. Automatic Pin-puller used by Maryland Coal Companies 554 35. Sketch of Body of Mine Cars used by Consolidation Coal Company... 555 3G. Sketch of Track Arrangement at Ocean No. 1, Consolidation Coal Company 562 37. Sketch showing Track Arrangement, Ocean No. 7, Consolidation Coal Company 566 38. Sketch showing Main Tipple, Ocean No. 7, Consolidation Coal Com- pany 568 39. Sketch showing Rocker for Dumping Coal used by Consolidation Coal Company 569 40. Sketch of Track Arrangement, Ocean No. 8, Consolidation Coal Com- pany 570 41. Sketch showing Track Arrangement, Union No. 1, Georges Creek Coal and Iron Company 574 42. Sketch of Basket employed in Loading Cars by Georges Creek Coal and Iron Company 579 43. Sketch showing Track Arrangement. Union Nos. 9 and 10, Georges Creek Coal and Iron Company 582 44. Sketch showing Arrangement of Tipple and Prop-lift, Pine Hill, Georges Creek Coal and Iron Company 583 45. Sketch showing Track Arrangement at Appleton and Kingsland Mines, Maryland Coal Company 587 46. Sketch showing Track Arrangements, New Detmold Mine, Maryland Coal Company 588 47. Sketch showing Tracks and Three-chute Tipple, Jackson Mine, Amer- ican Coal Company 590 MARYLAND GEOLOGICAL SURVEY 17 FIGURE PAGE 48. Sketch showing Tipple and Tracks, Koontz Mine, New Central Coal Company 592 49. Sketch showing Tipple and Plane, Morrison Mine, Frosthurg Coal Company 596 50. Sketch showing Track Arrangements and Tipples, Moscow Mines.... 602 51. Sketch showing Plan of Haulage System, Shamrock Mine, Lonaconing Coal Company 605 52. Tipple of the Barnum and Lay Mines, Monroe Mining Company.... 008 53. Tipples of the Elaine Mining Company and Garrett County Coal Company at Dill 612 54. Track Arrangement of the Elaine Mining Company 613 55. View of Calorimeter used in testing coals 623 MARYLAND

GEOLOGICAL SURVEY

VOLUME SIX

BALTIMORE THE JOHNS HOPKINS PRESS 1906 ILLUSTRATIONS ATE FACING PAGE I. View of Model of the State of Maryland 29 II. View of the State-house at Annapolis 32 III. Views of Coastal Plain Scenery 48 Fig. 1.—View of Talbot terrace showing Wicomico escarpment, Kent County. Fig. 2.—View of Calvert Cliffs on Chesapeake Bay, Calvert County. IV. Views of Coastal Plain Scenery 64 Fig. i _view of tributary of the Choptank, Talbot County. Fig. 2.—View of Sunderland terrace showing Lafayette escarpment, St. Mary's County. V. Views of Piedmont Scenery 80 Fig. 1.—Patapsco Valley at the mouth of Price's Run, Balti- more County. Fig. 2.—Level surface of Piedmont Plateau away from main drainage lines, Cecil County. VI. Views of Appalachian Scenery 96 Fig. 1.—View of Cumberland showing the Narrows of Wills Mountain, Allegany County. Fig. 2.—View of the Valley of Monroe Run, cut in the old peneplain, Garrett County. VII. View of Appalachian Scenery. Georges Creek Valley, near Barton, Allegany County H2 VIII. Views showing Geological Formations of the Piedmont Plateau 128 Fig. 1.—Granite quarry near Woodstock, Baltimore County. Fig. 2.—Contorted schist above Bald Friar, Cecil County. IX. Views showing Geological Formations of the Appalachian Region Fig. 1.—View of folded Silurian rocks near Hancock, Washington County. Fig. 2.—View of horizontal Carboniferous sandstone. Swal- low Falls, Garrett County. X. Views showing Geological Formations of the Coastal Plain... 160 Fig. 1.—View of Miocene beds. Cove Point, Calvert County. Fig. 2.—View of Pleistocene beds showing fossil shells. Corn- field Harbor, St. Mary's County. 20 ILLUSTRATIONS PLATE FACING PAGE XI. Views of Maryland Coal Mining Industry 176 Fig. 1.—View of Outcrop of Pittsburg seam, near Lonacon- ing, Allegany County. Pig. 2.—View of Consolidation Coal Company, Ocean No. 7, Allegany County. XII. Views of Maryland Building-Stone Industry 192 Fig. 1.—View of McClenahan Granite Quarry, Port Deposit, Cecil County. Fig. 2.—Thirty-eight-ton monolith. Beaver Dam Quarry, Baltimore County. XIII. Views of Maryland Clay Industry 208 Fig. 1.—Shale bank of Queen City Brick and Tile Company, Cumberland, Allegany County. Fig. 2.—Pit of Washington Hydraulic-Press Brick Company, Harman, Anne Arundel County. XIV. Views of Maryland Farming Lands 224 Fig. 1.—Valley farm-lands of the Piedmont Plateau, with Monocacy aqueduct, Frederick County. Fig. 2.—Level farm-lands of the Coastal Plain, Talbot County. XV. Views of Maryland Hydrography 240 Fig. 1.—The Youghiogheny, near Oakland, Garrett County. Fig. 2.—The Potomac at Williamsport, Washington County. XVI. dharacteristic Fossils of Maryland Formations, Cambrian- Ordovician 252 XVII. Characteristic Fossils of Maryland Formations, Silurian- Devonian 253 XVIII. Characteristic Fossils of Maryland Formations, Carboniferous- Permian 254 XIX. Characteristic Fossils of Maryland Formations, Triassic- Jurassic (?) 255 XX. Characteristic Fossils of Maryland Formations, Cretaceous.. . 256 XXL Characteristic Fossils of Maryland Formations, Eocene 257 XXII. Characteristic Fossils of Maryland Formations, Miocene 258 XXIII. Characteristic Fossils of Maryland Formations, Pleistocene.. 259 XXIV. Maryland Geological Survey Exhibit, Buffalo, 1901 264 Fig. 1.—General View of Exhibit. Fig. 2.—Near View of Exhibit. XXV. Maryland Geological Survey Exhibit, Charleston, 1902 268 Fig. 1.—General View of Exhibit. Fig. 2.—Building-stones, Granite, Marble, Slate, etc. XXVI. General View of Maryland Geological Survey Exhibit, St. Louis, 1904 270 ILLUSTRATIONS 21 PLATE facing page XXVII. Maryland Geological Survey Exhibit, St. Louis, 1904 272 Fig. 1.—View looking South. Fig. 2.—View looking North. XXVIII. Maryland Geological Survey Exhibit, St. Louis, 1904 274 Fig. 1.—Building-stones, Granite. Marble, Slate, etc. Fig. 2.—Decorative-stones, Marble, Serpentine, etc. XXIX. Maryland Geological Survey Exhibit, St. Louis, 1904 276 Fig. 1.—Coals, Flints, and Feldspars. Fig. 2.—Iron Ores, Cements, and Lime Products. XXX. Maryland Geological Survey Exhibit, St. Louis, 1904 278 Fig. 1.—Clay Products, Fire-brick, and Tile. Fig. 2.—Clay Products, Pottery, Terra Cotta, and Enameled Brick. XXXI. Fig. 1.—Churchviile-Worthington Corner Road, Harford County, Before Improvement 340 Fig. 2.—The Same, After Improvement 340 Fig. 3.—Earlton-Havre de Grace Road, Harford County, Before Improvement 340 Fig. 4.—The Same, After Improvement 340 XXXII. Fig. 1.—Churchviile-Worthington Corner Road, Harford County, Before Improvement 348 Fig. 2.—The Same, After Improvement 348 Fig. 3.—Wilkens Avenue, Baltimore County, Before Improve- ment 348 Fig. 4.—The Same, After Improvement 348 XXXIII, Fig. 1.—Aiken Avenue, Cecil County, Before Improvement.. 356 Fig. 2.—The Same, After Improvement 356 Fig. 3.—Garrison Road, Green Spring Valley, Baltimore County, Before Improvement 356 Fig. 4.-—Earlton-Havre de Grace Road, Harford County, After Improvement 356 XXXIV. Fig. 1.—Churchviile-Worthington Corner Road, Harford County, Before Improvement 372 Fig. 2.—The Same, After Improvement 372 Figs. 3, 4.—Earlton-Havre de Grace Road, Harford County, After Improvement 372 XXXV. Pig. 1.—Federalsburg-Houston's Branch Road, Caroline County, Before Improvement 388 Fig. 2.—The Same, After Improvement 388 XXXVI. Map Showing Counties of Maryland During the Period 1638- 1650 424 XXXVII. The Same, Period 1650-1654 432 XXXVIII. " Period 1654-1657 440 XXXIX. " Period 1657-1660 448 XL. " Period 1660-1670 456 23 ILLUSTRATIONS plate facing page XLI. The Same, Period 1670-1680 464 XLII. " Period 1680-1700 472 XLIII. " Period 1700-1740 480 XLIV. " Period 1740-1773 488 XLV. " Period 1773-1776 490 XLVI. " Period 1776-1789 512 XLVII. " Period 1789-1836 528 XLVIII. " Period 1836-1850 536 XLIX. " Period 1850-1867 544 h. " Period 1867-1872 552 LI. " Period 1872-1907 560

FIGURE PAGE 1. Map of Maryland showing Boundaries 35 2. Map of Maryland showing the Density of Population by Counties. . 37 3. Map of Maryland showing the Physiographic Provinces 56 4. Diagram showing relative position of Coastal Plain Terraces 67 5. Diagram showing relative annual values of Maryland Mineral Products 6. Map showing location of Maryland Coal Basins 168 7. Generalized section showing relative positions of Maryland coal seams 170 8. Map of Maryland showing the distribution of building-stones 172 9. Map of Maryland showing the distribution of clays 192 10. Map of Maryland showing the mean annual temperatures 224 11. Mean temperatures in the four climatic divisions of Maryland 225 12. Map of Maryland showing the Advent of Spring 231 13. Map of Maryland showing the Annual Precipitation in Inches 232 14. Fluctuations in Annual Precipitation at Baltimore, 1871-1898 234 15. Total monthly precipitation during Dry, Normal, and Wet years. ... 235 16. Relative Frequency of Clear, Partly Cloudy, and Cloudy days 237 17. Map of Maryland showing Drainage Basins 239 18. Map of Maryland showing lines of Equal Magnetic Declination 242 19. Plan of Annapolis Exhibit 277 Geological Map of Maryland pocket MARYLAND

GEOLOGICAL SURVEY

VOLUME SEVEN

BALTIMORE JOHNS HOPKINS PRESS 1908 #

ILLUSTRATIONS PLATE FACING PAGE I. View of new monument erected by Resurvey Commission, 1902 V II. Views of monuments along Mason and Dixon Line. Fig. 1.—Granite monument at northeast corner of Maryland 30 Fig. 2.—New monument in an original mound, Martin's Mountain 30 III. Views of monuments along Mason and Dixon Line. Fig. 1.—Granite monument at north end of Deakins Line 34 Fig. 2.—Granite monument at north end of Michler Line 34 IV-LXXIII. Charts of Resurvey showing line and property boundaries.. 102 LXXIV. Reproduction of Captain John Smith map of 1608 118 LXXV. Reproduction of N. J. Vlsscher map of 1659 142 LXXVI. Reproduction of Augustine Herrman map of 1670 150 LXXVII. Reproduction of Benjamin Eastburn map of 1740 166 LXXVIII. Map showing lines run to determine tangent point 182 LXXIX. Map showing progress of Mason and Dixon Survey 190 LXXX. Views of monuments along Mason and Dixon Line. Fig. 1.—Original cornerstone showing Baltimore arms.. 194 Fig. 2.—Original cornerstone showing Penn arms 194 LXXXI. Views of monuments along Mason and Dixon Line. Fig. 1.—Original milestone, repaired and reset 198 Fig. 2.—(New monument of 1902, set in old mound 198 LXXXII. Facsimile of Parchment map prepared by Mason and Dixon in 1768 ."In pocket. Figure on page 1. Diagram showing method of crossing Susquehanna river 45 2. Diagram showing trial lines of original survey and resurvey 76 3. Lord Baltimore map of 1635 (reduced) 110 4. Map showing extent of settlement when Pennsylvania was granted.. 123 5. Maps showing relation of 40° N. lat. to Chesapeake Bay 132 6. Maps showing relation of 40° N. lat. to Chesapeake Bay 133 7. Map showing approximate location of first boundary line 136 8. Map showing transpenlnsular line and "middle point" 180 MARYLAND

GEOLOGICAL SURVEY

VOLUME EIGHT

BALTIMORE THE JOHNS HOPKINS PRESS 1909 ILLUSTRATIONS PLATE facing page I. Legislative Road below Barrellvllle, Allegany County. Im- proved Section along Jennings Run 31 II. Fig. 1.-—Old Culvert on River Road between Cumberland and Cresaptown, Allegany County 36 Fig. 2.—Improved Culvert on River Road between Cumberland and Cresaptown, Allegany County. Built by County Roads Engineer 36 III. Fig. 1.—Chesapeake Avenue, Baltimore County. Before Im- provement 42 Pig. 2.—Chesapeake Avenue, Baltimore County. After Im- provement by County Roads Engineer 42 IV. Fig. 1.—Section of Gwynn Oak Avenue, Baltimore County. Before Improvement 46 Fig. 2.—Section of Gwynn Oak Avenue, Baltimore County. After Improvement by State Aid 46 V. Fig. 1.—Section of Gwynn Oak Avenue, Baltimore County. Before Improvement 56 Fig. 2. Section of Gwynn Oak Avenue, Baltimore County. After Improvement under State Aid 56 VI. Old Bridge Across Choptank River, Greensboro-Denton Road, Caroline County 68 VII. New Bridge Across Choptank River, Greensboro-Denton Road, Caroline County. Built under State Aid Law 70 VIII. Fig. 1.—Houston's Branch Road, Caroline Road. Before Im- provement 72 Pig. 2.—Houston's Branch Road, Caroline County. After Im- provement under State Aid 72 IX. The Geological Formations of Maryland 100 X. Plan and Profile of the Hoffman Drainage Tunnel 164 XI. Plan of a Portion of the Workings of the Hoffman Mine of the Consolidation Coal Company 172 XII. Views of Eastern Piedmont Quarries. Fig. 1.—Beaver Dam Quarry, Cockeysvllle 336 Fig. 2.—West End of Ditman Quarry, Texas — 336 XIII. Typical Limestones of Eastern Piedmont. Fig. 1.—" Alum Stone," Ditman Quarry, Texas. White Marble Composed of Large Crystals of Calcite 342 Fig. 2.—Banded Magnesian Stone Showing White Crystalline Crossed by Band Impregnated with Brown Mica 342 22 ILLUSTRATIONS PLATE FACING PAGE XIV. Views of Western Piedmont Quarries. Fig. I.—Staub Quarry, Little Pipe Creek, near Wakefleld, Carroll County 352 Fig. 2.—Rinehart Quarry, South of Union Bridge, Frederick County 352 XV. Views of Quarry and Plant of the Tidewater Portland Cement Company, near Union Bridge, Carroll County. Pig. 1.—Limestone Quarry of Tidewater Portland Cement Company, Union Bridge 360 Fig. 2.—View of Proposed Plant of Tidewater Portland Cement Company 360 XVI. Typical Limestones of Western Piedmont. Pig. 1.—Crystalline Limestone, Pine Grained and Creamy White, Tidewater Portland Cement Company Quarry, Union Bridge 368 Fig. 2.—Argillaceous or Shaly Limestone, Folding Brought Out by Weathering, Clear Ridge 368 XVII. Typical Volcanic Rocks of Western Piedmont. Fig. 1.—" Honeycomb Rock," Amygdaloidal Catoctin Schist or Basic Volcanic Rock, Westminster 376 Fig. 2.—Slaty Metarhyolite, or Acid Volcanic Rock, with Feldspar Phenocrysts. Sam's Creek 376 XVIII. Views of Frederick Valley Quarries. Fig. 1.—Kilns and Quarry of S. W. Barrick and Son's, Le Gore 384 Fig. 2.—Quarry and Kilns of Le Gore Combination Lime Com- pany, Le Gore 384 XIX. Views of Frederick Valley Quarries. Fig. 1.—Stimmel Quarry, Fountain Rock Lime Company, Fountain Rock 392 Fig. 2.—South End of Quarry, M. J. Grove Lime Company, Frederick 392 XX. Views of Hagerstown Valley Quarries. Pig. 1.—Quarry of S. P. Angle, Hagerstown 400 Fig. 2.—Quarry of Potomac Valley Stone and Lime Company, Pinesburg 400 XXI. Views of Portland Cement Operations, Hagerstown Valley. Fig. 1.—Quarry of the Security Cement and Lime Company, Security 408 Fig. 2.—Plant of the Security Cement and Lime Company, Security 408 XXII. " Edgewise Beds " Characteristic of Elbrook and Conococheague Formations. Hagerstown Valley, Washington County 416 XXIII. Views of Natural Cement Operations, Western Washington County. Fig. 1.—View of Folded Strata, Round Top, near Hancock.... 432 Fig. 2.—Old Natural Cement Plant, Round Top, near Hancock 432 ILLUSTRATIONS as PLATE FACING PAGE XXIV. Views of Allegany County Limestone Exposures. Fig. 1.—Greenbrier Limestone, West of Corriganville 448 Fig. 2.—Helderberg-Cayuga Limestones, Devil's Backbone, Corriganville 448 XXV. Views of Allegany County Cement-Rock Quarries. Fig. 1.—Quarry of Cumberland Hydraulic Cement Company, Cumberland ' 456 Fig. 2.—Quarry of Cumberland and Potomac Cement Com- pany, Potomac 456 XXVI. Map Showing the Limestones of Maryland in Pocket.

FIGURE PAGE 1. Columnar section showing relative positions of Maryland coal seams 105 2. Sketch of Track Arrangement at Ocean No. 1, Consolidation Coal Company 162 3. Sketch showing Track Arrangements, Ocean No. 7, Conso idation Coal Company 167 4. Sketch showing Main Tipple, Ocean No. 7, Consolidation Coal Com- pany 168 5. Sketch showing Rocker for Dumping Coal used by Consolidation Coal Company 169 6. Sketch of Track Arrangement, Ocean No. 8, Consolidation Coal Com- pany 170 7. Sketch showing Track Arrangement, Union Mine No. 1, Union Mining Company 176 8. Sketch of Basket employed in Loading Cars by Georges Creek Coal and Iron Company 179 9. Sketch showing Tracks and Three-chute Tipple, Jackson Mine, American Coal Company 183 10. Sketch showing Track Arrangement at Appleton and Kingsland Mines, Maryland Coal Company 186 11. Sketch showing Track Arrangement, New Detmold Mine, Maryland Coal Company 187 12. Sketch showing Tipple and Tracks, Koontz Mine, New Central Coal Company 189 13. Sketch showing Tipple and Plane, Morrison Mine, Frostburg Coal Mining Company 205 14. Tipples of Blaine Mining Company and Garrett County Coal and Mining Company, at Dill 218 15. Track Arrangement of the Blaine Mining Company 219 16. Diagram showing relative values of fluxing stones 245 17. Diagram showing method of determining thickness of horizontal beds 312 18. Diagram showing method of determining thickness of inclined beds.. 312 19. Diagram showing production of Natural and Portland Cements, 1890- 1908 329 20. Map of Maryland showing the Physiographic Provinces 331 21. Plan of arrangement of buildings. Tidewater Portland Cement Com- pany, Union Bridge 373 24 ILLUSTKATTONS FIGURE PAGE 22. Section showing geological structure across Hagerstown Valley (through Hagerstown) 400 23. Section showing geological structure across Hagerstown Valley (through Boonsboro) 407 24. Sketch showing location of samples from McComas-Humrichouse farm near Charlton 415 25. Plan of arrangement of buildings of Security Cement and Lime Com- pany, Security 422 26. Diagram showing source of samples analyzed from Corriganville.... 452 27. Diagram showing source of samples analyzed from Potomac 456 MARYLAND

GEOLOGICAL SURVEY

VOLUME NINE

BALTIMORE The Johns Hopkins Press 1911 ILLUSTRATIONS

PLATE FACING PAGE I. Cumberland-Mt. Savage Road, Allegany County. Improved under State Aid Law in 1909 33 II. Fig. 1.—Old Bridge on Cumberland-Mt. Savage Road, Allegany County 36 Fig. 2.—New Bridge on Cumberland-Mt. Savage Road, Allegany County 36 III. Fig. 1.—Bloomery Road, Caroline County, before improvement. 40 Fig. 2.—Bloomery Road, Caroline County, after improvement.. 40 IV. Fig. 1.—Reinforced concrete Bridge over Rock Creek, Kensing- ton Road, Montgomery County 48 Fig. 2.—Reinforced concrete Bridge over Rock Creek, Kensing- ton Road, Montgomery County 48 V. Map of Maryland showing roads proposed and constructed 78 VI. Map of Maryland showing the Highways built by the Maryland Geological Survey 120 VII. Map of Maryland showing Furnace Locations 128 VIII. Views of Maryland Iron Furnaces— Fig. 1.—Ruin of Blast Furnace, Lonaconing, Allegany County.. 13ti Fig. 2.—Catoctin Furnace, Thurmont, Frederick County 136 IX. Views of Maryland Iron Furnaces— Fig. 1.—Blast Furnaces, Maryland Steel Company, Sparrows Point, Baltimore County 152 Pig. 2.—Principio Furnace, Principio, Cecil County 152 X. Views of Maryland Iron Furnaces- Fig. 1.—Ruins of Elkridge Furnace, Elkridge, Howard County.. 164 Fig. 2.—Muirklrk Furnace, Muirkirk, Prince George's County.. 164 XI. Views of Maryland Iron Furnaces— Fig. 1.—Curtis Creek Furnace, Furnace Creek, Anne Arundel County 168 Pig. 2.—Nassawango Furnace (1900), near Snow Hill, Worcester County 168 XII. Map of Maryland showing distribution of Iron Ores 176 XIII. Index Map showing position of plates 178 XIV. Location of Limonite Ore Banks in parts of Washington County. 180 XV. Location of Ore Banks in part of Frederick County 192 XVI. Location of Ore Banks in parts of Carroll and Baltimore Coun- ties 208 XVII. View of Maryland Iron Ore Banks— Fig. 1.—Iron Ore at Contact of Limestone and Volcanics, Bach- man Valley, Carroll County 212 ILLUSTRATIONS 25 rLATE FACING PAGE Fig. 2.—Nodule of sandy iron carbonate in Arundel Formation, near Milton Avenue, Baltimore City 212 XVIII. Location of Ore Banks in parts of Baltimore and Harford Coun- ties 216 XIX. Location at which Bog Ore has been mined in Southeastern Maryland 228 XX. Location of Ore Banks In Garrett and Allegany Counties 240 XXI. View showing Nodular Ore in Arundel Clay, Anne Arundel County, Reynold's Ore Bank 256 XXII. Location of Ore Banks in parts of Harford and Baltimore Counties 260 XXIII. Location of Ore Banks in parts of Baltimore and Anne Arundel Counties 264 XXIV. Location of Ore Banks in parts of Baltimore, Howard, Anne Arundel and Prince George's Counties 272 XXV. Location of Ore Banks in parts of Frederick, Carroll and How- ard Counties 308 XXVI. Map showing Lines of Equal Magnetic Declination in Maryland for 1910 338

FIGURES PAGE L Fireback made at Fatuxent Furnace, 1738 171 2. Location of Ore Banks about North Mountain 185 3. Sketch showing development of ore bank one mile north of Catoctin Furnace 194 4. Diagram showing structure on east side of Catoctin Mountain. (After Keith) 197 5. Sketch showing ore workings at Chestnut Hill ore banks 209 6. Map showing location of Maryland coal basins 233 7. Generalized section showing Maryland coal seams 23o 8. Diagram showing position of Howard County magnetites 318 MARYLAND

GEOLOGICAL SURVEY

VOLUME TEN

BALTIMORE THE JOHNS HOPKINS PRESS 1918 ILLUSTRATIONS FIGURE PAGE 1. View of the State House at Annapolis 42 2. View of City Hall, Baltimore 43 3. View of Mason and Dixon Line monument stones 45 4. Map showing density of population 47 5. View of Wye House, a Colonial Mansion In Talbot County .ii 6. View of Homewo<5d, built by Charles Carroll of Carrollton in 1804. On grounds of the Johns Hopkins University 51 7. View of the historic Wye Oak, Wye Mills, Talbot County 54 8. Fort Frederick, Washington County, built in 1756. Where Washington fitted out his Expedition against Fort Duquesne in the French and Indian War 55 9. Entrance to the Chesapeake and Delaware Canal at Chesapeake City, Cecil County (51 10. Toll House on National Road, built after the State took control of the road in 1834 01 11. A modern highway near Princess Anne, Somerset County 02 12. The Baltimore and Ohio Railroad in 1830, 1832, and 1858 63 13. A modern all-steel coal train on the Baltimore and Ohio Railroad (i4 14. Map showing the physiographic provinces 71 15. Sand dunes near Ocean City, Worcester County 73 16. View of a sand spit, mouth of Fairlee Creek, Kent County 73 17. View showing the nearly-horizontal Miocene formations of the Calvert Cliffs, Calvert County 74 18. Diagram showing relative position of Coastal Plain Terraces 76 19. Geological section Port Deposit to Sassafras River 76 20. Geological section Washington to Calvert Cliffs 79 21. Geological section Cambridge to Atlantic Ocean 79 22. Geological section Westminster to Baltimore 82 23. Geological section Green Spring Valley to Federal Hill 83 24. View of the gorge of the Susquehanna River between Harford and Cecil counties 85 25. The Great Falls of the Potomac 85 26. Geological section Big Savage Mountain to the Blue Ridge 91 27. View of the valley of Monroe Run eroded in the Schooley peneplain of the Alleghany Plateau 92 28. Crabtree Creek 93 29. View of Swallow Falls, Youghiogheny Valley, Garrett County 95 30. View showing folded Silurian rocks of the Appalachian region, Wash- ington County 96 31. Map showing mean annual temperatures 99 32. Map showing advent of spring 100 24 ILLUSTKATIONS

FIGURE PAGE 33. Map showing rainfall 101 34. Beginning of a mine at an outcrop of the Big Vein near Lonaconing, Allegany County 104 35. Main entrance to Bluebaugh Mine, near Barrelville, Allegany County.. 104 36. Map showing distribution of the clays 106 37. Beaver Dam Marble quarry, Cockeysville, Baltimore County 107 38. Granite quarry at Port Deposit 108 39. Map showing distribution of building stones Ill 40. Map showing the valuations of farm buildings 117 41. Map showing the relative annual production of corn. 118 42. Map showing the relative annual production of wheat. 119 43. Kent County farm lands of the Talbot terrace plain 121 44. Harvesting wheat in Kent County 121 45. Farming lands near Leonardtown, St. Mary's County 122 46. Tobacco field in Charles County 122 47. Map showing the acreage in canning crops 123 48. Map showing the'relative annual production of tobacco 124 49. Type of barn in Carroll County 126 50. Cattle raising and dairying in Carroll County 126 51. Map showing the relative annual production of milk 127 52. Map showing the relative annual production of hay 128 53. Farming and orchard land, Allegany County 129 54. Sugar-maple grove near Bittinger, Garrett County 129 55. Saplings of Loblolly Pine, St. Mary's County 130 56. Hemlock forest. Sideling Creek, Washington County 131 57. A boat-load of oysters, Somerset County I33 58. A fish hatchery I33 59. An oyster and crab-packing plant 134 60. Shucking oysters I30 61. Icing oysters 135 62. The interior of a Baltimore pottery I38 63. A blast furnace of the Bethlehem Steel Company, Sparrows Point 139 64. Ore docks at Sparrows Point I39 65. Delivering sweet corn at cannery, Easton, Talbot County 140 66. View of Baltimore harbor and sky-line 141 67. The lower harbor from historic Fort McHenry 142 68. Light Street wharves at the head of Baltimore's harbor 142 69. View of Cumberland and the " Narrows " of Wills Mountain 143 70. View of Annapolis showing the Naval Academy 145 71. View of Frostburg 145 72. Map showing the Physiographic Provinces 173 73. Diagram showing relative position of Coastal Plain terraces 175 74. Map showing the annual precipitation 226 75. Map showing the drainage basins 227 76. Diagrammatic section showing the relation of water table to surface Irregularities 232 ILLUSTRATIONS

FIGURE PAGE 77. Diagram showing the loss in head by friction and leakage 232 78. Diagram illustrating artesian conditions In the Coastal Plain 233 79. Diagram illustrating artesian conditions in Western Maryland 2.34 80. Diagram showing an ordinary hillside spring 235 81. Diagram showing a deep-seated spring 235 82. Diagram showing right and wrong locations for wells 237 83. Diagram showing relations between depth and an unfailing supply of water 237 84. Diagram showing the action of clays or shales in confining water in sand or sandstone 238 85. Map showing Lower Cretaceous waters 241 86. Map showing Upper Cretaceous waters 244 87. Map showing Eocene waters 246 88. Map showing Lower Miocene waters 248 89. Map showing Upper Miocene waters 250 90. Map of the Baltimore district showing water horizons 330 91. Plan of the Montebello filters 494 92. View of a Montebello filter unit 495 93. View of Lime Mixers and Lime Tanks 496 94. View of Chemical Feed Controllers 497 95. View of Upper Service Pumping Station 498 96. View of Coagulation Basins 499 MARYLAND

GEOLOGICAL SURVEY

VOLUME ELEVEN

BALTIMORE THE JOHNS HOPKINS PRESS 1922 ILLUSTRATIONS PART I plate facing page I. Fig. 1.—Map showing location of coal basins of Maryland 40 Fig. 2.—View of Connoquenessing sandstone, Swallow Falls, Garrett, County 40 II. Fig. 1.—View of Lower Sharon Coal and Sandstone, near Westemport, Allegany County 176 Fig- 2.—View of Consolidation Coal Company, Ocean No. 1 176 III. Fig. 1.—Davis Coal and Coke Company, Henry No. 1 192 Fig. 2.—Davis Coal and Coke Company, Town of Kempton 192 IV. Fig. 1.—Davis Coal and Coke Company, Tipple at Kempton 208 Fig. 2.—View in Davis Coal and Coke Company's mine at Kempton... 208 V. Map showing outcrop of coal seams 288 VI. Columnar sections (in pocket) VII. Columnar section of the Georges Creek Valley (in pocket) FIGURE PAGE 1. Room and panel in panel system 139 2. Set of timber ; 141 3. Prop witjpi crossbar set in rib 141 4. Prop and set of timber 141 5. Gob and set of timber 141 6. Prop and cap piece 141 7. Prop with crossbar wide cap piece 141 8. Diagram showing method of drilling 143 9. Diagram showing method employed in recovering coal from the pillars.. 145 10. Miner's carbide lamp 149

PART II PLATE FACING PAGE I. Fig. 1.—View showing foot of plane of the Union Mining Company.... 320 Fig. 2.—View of clay dump and tram equipment of the Union Mining Company 320 II. Fig. 1.—View of brick plant of the Maryland Coal Company near Lona- coning 352 Fig. 2.—View showing the new plant of the Maryland Coal Company.. 352 III. Fig. 1.—View of tipple at head of plane at the Benson mine 368 Fig. 2.—View of entrance to Mine No. 6 of the Union Mining Company. 368 IV. Fig. 1.—View of tipple at Mine No. 5 of the Union Mining Company.. 384 Fig. 2.—View of tipple and auto truck of Caldwell mine 384 24 ILLUSTKATIONS

FIGURE PAGE 1. Graph showing variation in composition of kaolins and ball clays 303 2. Graph showing variation in composition of fire and flint clays 303 3. Graph showing variation in composition of stoneware and terra cotta clays. 303 4. Graph showing relation of composition to fineness of grain 308 5. Graph showing relation of water for tempering to air shrinkage..; 313 6. Graph showing range of workability according to amount of water used in tempering 317 7. Graph showing fusion temperatures 321 8. Graph showing intervals between incipient fusion, vitrification, and viscosity 323 9. Graph showing composition arranged according to fusion temperatures... 324 10. Graph showing porosity of clays burned at different temperatures 327 11. Diagram showing temperatures at which clays for different purposes are burned 328 12. Technology of fire clays and fire-clay refractories 1. 380 2 13. Graph showing effect of additions of K 0, Na=0, CaO, and MgO 388 14. Ditto 389 15. Composition temperature diagram 395 16. Graph showing classification of fire clays 412 17-107. Graphs showing properties of clays sampled 491-534 MARYLAND

GEOLOGICAL SURVEY

VOLUME TWELVE

BALTIMORE JOHNS HOPKINS PRESS 1928 ILLUSTRATIONS Facing page Plate I. Index map of northeastern Maryland showing the positions of plates giving the location of feldspar quarries 96 II. Location of feldspar quarries in Cecil and Harford counties showing conditions before Conowingo Dam erection 104 III. Location of feldspar quarries in part of Baltimore County and in * Montgomery County 112 IV. Location of feldspar quarries in part of Baltimore County and in Carroll and Howard counties 120 V. Map showing the locations of present and past flint mills, and positions of plates giving location of flint quarries 128 VI. Location of flint quarries in part of Harford County 136 VII. Location of flint quarries in part of Baltimore, Carroll, and Howard counties 144 VIII. View of Annapolis Rock White Flint deposit 152 IX. Map of northeastern Maryland showing areas of serpentine rock and position of maps giving location of localities at which chrome ores have been produced 160 X. Map of a portion of Cecil County showing serpentine areas and localities at which chrome ores have been produced 168 XI. Map of a portion of Harford County showing serpentine areas and localities at which chrome ores have been produced 176 XII. Map of portions of Baltimore County showing serpentine areas and localities at which chrome ores have been produced 184 XIII. Map of a portion of Montgomery County showing locality at which chrome ores were mined 192 XIV. Fig. 1.—View of serpentine quarry and saw-mill at Cardiff 1901... 256 Fig. 2.—View of serpentine quarry at Cardiff 1928 256 XV. Fig. 1.—View of serpentine barrens at Broad Creek 264 Fig. 2.—View of serpentine barrens at Soldiers Delight 264 XVI. Map showing serpentine areas in Harford County and rock specimen numbers 280

Figure p0(,e 1. Profile of Pleistocene terraces showing deposition of molding sand at the inner margin of the Wicomico terrace 44 2. Longitudinal section and plan of a buddle used in washing chrome sands 166 3. Screen analysis curves of five sand chrome samples showing per- centage of each mesh size 169 4. Screen analysis curves of five sand chrome samples showing per- centage above indicated mesh size 169 Illustrations

Figure I'nge 5. Screen analysis of magnetic and non-magnetic portions of Sample 1. 170 6. Screen analysis of magnetic and non-magnetic portions of Sample IV 173 7. Sketch of surface workings of the Reed Mine 181 8. Textures of serpentine formed by the alteration of 1. olivine, 2. amphibole, and 3. pyroxene respectively 247 9. Figure showing central cleavage lines of serpentine surrounded by magnesite 275 MARYLAND

GEOLOGICAL SURVEY

VOLUME THIRTEEN

BALTIMORE JOHNS HOPKINS PRESS 1937 ILLUSTRATIONS Facing Plate Page I. General map showing the areas described in this volume 34 II. Fig. 1.—Flowage folds in Baltimore gneiss, one-half mile east of Alberton 46 Fig. 2.—Shear fold in isoclinally-folded ribbon gneiss, A strong cleavage parallels the axial plane and dips gently north. South- east bay of Lake Roland 46 III. Fig. 1.—Combination of flow and shear folds in Baltimore gneiss. 50 Fig. 2.—Fracture cleavagc in Wissachickon schist, seven miles north of Conowingo Dam, east side of Susquehanna River 50 IV. Fig. I.—Flow cleavage transecting bedding in Vintage Dolomite. Burnt Mills, Pennsylvania 56 Fig. 2.—Flow cleavage in fan-like arrangement 56 V. Fig. 1.—Cleavage transecting bedding in Setters Formation, one- half mile northeast of Notch Cliff 60 Fig. 2.—Weathered Setters Quartzite showing vertical bedding, crossed by nearly horizontal fracture cleavage. Long Green Creek 60 VI. Figs. 1 -|- 2.—Photomicrographs of fracture cleavage in Wissahickon Schist, Prettyboy Dam 66 VII. Fig. 1.—Aligned blebs in volcanic rocks of Frederick County, Maryland 70 Fig. 2.—Elongated components in conglomerate of Conestoga Lime- stone, transected by cross fracture, Burnt Mills, Pennsylvania. . 70 VIII. Fig. 1.—Linear stretching in Setters quartzite, transected by cross fractures. Quarry on east side of Brice Run, north limb of Jew Bottom Anticline 74 Fig. 2.—Shear fractures produced artificially in clay 74 IX. Fig. 1.—Photomicrograph of Antietam mica schist. Same section as Figs. 10-13 (Statistical diagrams). Road three miles north from Marticville, Pennsylvania 90 Fig. 2.—Oriented specimen used for statistical diagram in Figs. 10-13

Facing Plate Page XXXV. Structure map of the area of volcanic rocks in Cecil County, Mary- land In pocket XXXVI. Fig. 1.—Foliation cutting bands in the Baltimore gneiss. South bluff of Lake Roland 220 Fig. 2.—Feathery serpentine, natural scale. One mile north of Union Dam 220 XXXVII. Fig. la.—Specimen of chloritized amphibolite. Patapsco River southeast of Hollofield 222 Fig. lb.—Honeycomb ironstone with residual serpentine. Cedar Branch. Natural size 222 Fig. 2.—Gabbro pegmatite north of Union Dam 222 XXXVII1. Fig. 1.—Thin acid bands in amphibolite. Patapsco River one mile southeast of Hollofield 224 Fig. 2.—Joints refracted by banding, Baltimore and Ohio Railroad, south of Hollofield 224 XXXIX. Fig. 1.—Banded ultrabasics. Northeast of Western Maryland Railroad and Gwynns Falls Parkway 228 Fig. 2.—Schistose zone in gabbro. Western Maryland Railroad at Sudbrook Park 228 XL. Fig. 1.—Sharply folded linear foliation of amphibolite. Specimen from south of Union Dam, Baltimore County. Natural size 2:j() Fig. 2.—Cross jointing. Patapsco River, one mile southeast of Hollofield 2:50 XLI. Geologic map of the area underlain by the Baltimore gabbro showing the distribution of primary and secondary structures In pocket XLII. Fig. 1.—The canal west of Summit Bridge, Delaware, before the recent dredging operations 244 Fig. 2.—The canal east of Summit Bridge, Delaware, during the recent dredging operations 244 XLIII. Fig. 1.—The Pleistocene overlying the Raritan formation 1200 feet east of Chesapeake City bridge. Station 76 + 400 N 266 Fig. 2.—Haiymenites major in Englishtown sand 50 feet east of the Philadelphia, Baltimore, and Washington Railroad bridge. Sta- tion 45 -j- 280 S 260 XL1V. Fig. 1.—The Englishtown-Marshalltown contact at station 52 150 S. The Englishtown contains Halymenites major 2BS Fig. 2.—Halymenites major in Englishtown sand at above station .. 268 XLV. Fig. 1.—The irregular contact between the Magothy formation and the Crosswicks clay, one mile west of Summit Bridge at station 57 + 480 N 270 Fig. 2.—The Englishtown-Marshalltown contact 100 feet west of the Philadelphia, Baltimore, and Washington Railroad bridge. Sta- tion 45 + 450 S 270 XLVI. Section A. Bank of canal approximately 1600 feet east of Mary- land-Delaware line (between stations 66 + 375 and 66 -f- 225). 276 Section B. Bank of canal approximately 2000 feet west of Summit Bridge (between stations 54 + 450 and 54 -j- 050) 276 Section C. Bank of canal approximately one and a half miles west of St. Georges Bridge (between stations 36 + 775 and 36 + 665 276 Section D. Bank of canal approximately one-quarter mile east of St. Georges Bridge (between stations 28 865 and 28 + 735 276 Illustrations 23

Figure Pane 1. Schematic block diagram showing the elements of a fold 52 2. Diagram of a fold which is located in a coordinate system of three axes 54 3. Diagram showing a bent fold. Note consistent thickness of bedding with reference to a center of curvature. Half arrows indicate relative direction of slippage. Full arrows indicate areas of tension and compression within the crest of the fold 56 4. Diagram of a shear fold which is the result of slippage on subparallel planes in the direction of the arrows 57 5. Diagram showing the relation between cleavage and bedding in a fold 65 6. Diagram showing axial plane cleavage in a shear fold 66 7. Folded quartz veins in Wissahiekon schist. Susquehanna River section 67 8. Combination of bedding, flow cleavage, and fracture cleavage. (Diagram) 68 9. Bedding in Conestoga limestone almost obliterated by slippage along cleavage planes. Burnt Mills, Pennsylvania. Height of the exposure 10 feet 71 10 13. Statistical diagrams of mineral orientations in Antietam schist 90 10. Orientation of biotite cleavage, 200 grains. Contours; 1-2-3-4-5-6- 8-10-12 per cent. Solid black area from 1217 per cent 90 11. Orientation of muscovite cleavage. 300 grains. Contours: 1-2-3-4- 5-6-7-8-9-10 per cent 90 12. Orientation of inclusions in albite crystals. 160 inclusions. Con- tours: 2-4-6-8-10-12-14-16-18 per cent and over. Solid black over 18 per cent 90 13. Orientation of quartz axes (e). 200 grains. Contours: 1-1^-2-3-3^ per cent. Black area over 3^ per cent 90 14. Diagram showing directions of joints in Setters quartzite 96 15. The same joints shown in a projection of their poles in a spherical equal area net 96 16. Sketch showing displacement of quartz dikes and joint along re- gional tension joints. Displacements average two inches. Small closely spaced joints. Length of N-line equal 2 feet 141 17. Trend of the anticlinal axes of Baltimore gneiss domes in Maryland. 154 18. Diagram showing obliteration of the unconformity along the flanks of domes and the types of folding 162 19-26 Statistical diagrams of the direction of jointing 19. Joints in Baltimore gneiss. Malvern Avenue, near Ruxton 171 20. Joints in Baltimore gneiss at Cromwell Bridge 171 21. Joints in Baltimore gneiss in the Stone quarry at Falls Road 172 22. Joints in Baltimore gneiss. Gwynns Falls and Hilton quarries.. . 172 23. Joints in Setters quartzite. Quarry one-quarter mile east of Tobin 177 24. Joints in quartzite. Waters quarry 177 25. Joints in quartzite. Rustic quarry 177 26. Joints in quartzite quarry at Cromwell Bridge 177 27. Structural elements in folded ribbon gneiss near Clarksville. The horizontal plane is a cross joint 179 Illustrations Figure I'age 28. Contact of amphibolite (G) with amphibolite schist (A). Forest Park Avenue at Hillsdale 222 29. Section of mixed Wissahickon schist (W) and amphibolite (A). Pennsylvania Railroad at Mount Washington 228 30. Amphibolite (G) in Wissahickon schist (W). Baltimore and Ohio Railroad south of Hollofield 229 31. Relation of secondary structure to banding, one mile southeast of Hollofield 230 32. Belt of Upper Cretaceous outcrops in the Chesapeake and Delaware Canal Region 243 33. Section accompanying Plate XLIII, Fig. 1 26(5 34. Section accompanying Plate XLIII, Fig. 2 26(5 35. Section accompanying Plate XLIV, Fig. 1 268 36. Section accompanying Plate XLV, Fig. 2 268 37. Index map showing location of sections along the canal 275