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FIGURE

LIST OF ILLUSTRATIONS

31. Reversed Fault

32. Single Thrust-plane

33. Section across Coal-basin of Mons (M. Bertrand)

34.

Section from Quinaig to Head of Glenbeg (Geol. Survey)

35. Synclinal Double-fold

36. Anticlinal Double-fold

37. Diagram of Mountain Flexures

39. Synclinal Valley shifting toward Anticlinal Axis

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42. Section across the Schortenkopf, Bavarian Alps (E. Fraas) Section across the Kaisergebirge, Eastern Alps (E. Fraas) Section across the Val d'Uina (Gümbel)

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46. Section across the Northern Limestone Alps (E. Fraas)

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47. Section across the Diablerets (Renevier).

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53.

48. Section across Dent de Morcles (Renevier)

49. Inversion and Overthrust in the Mountains South of the Lake of

Wallenstadt (E. Fraas, after A. Heim)

50. Symmetrical Flexures of the Jura Mountains

51.

Section across Western part of the Jura Mountains (P. Choffat)

52. Section across part of the Sandstone-zone of the Middle Carpathians

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Section across part of the Middle Carpathians (Vacek)

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54. Section across the Appalachian Ridges of Pennsylvania (H. D. Rogers)

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55. Unsymmetrical Folds, giving rise to Escarpments and Ridges
56. Structure of the Ardennes (after Cornet and Briart).
57. Diagrammatic Section across a Plateau of Erosion

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58. Section across portion of Southern Uplands, showing Old Red Sandstone resting upon Plain of Erosion

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59. Section from Glen Lyon to Carn Chois (Geol. Survey) 60. Section of Normal Fault.

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61. Normal Fault, with High Ground on Downthrow Side
62. Normal Fault, with High Ground on Upcast Side.
63. Faults in Queantoweep Valley, Grand Cañon District (Dutton)
64. Ranges of the Great Basin (Hinman, after Gilbert: length of section,

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65. Section from the Mediterranean across the Mountains of Palestine to

the Mountains of Moab (after M. Blanckenhorn).

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66. Section across the Vosges and the Black Forest (after Penck)

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FIGURE

67. Section of Coal-measures near Cambusnethan, Lanarkshire, on a true scale

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68. Section on a true scale across 64 Tynedale Fault," Newcastle Coal-field 168 69. Section across Great Fault bounding the Highlands near Birnam,

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70. Section across Great Fault bounding the Southern Uplands 71. Diagram Section across Horstgebirge

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Mountain of Granite

Plain of Granite overlooked by Mountains of Schists, etc.

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74. Diagrammatic Section of a Laccolith showing Dome-shaped Elevation of Surface above the Intrusive Rock (after G. K. Gilbert) View of Necks-Cores of old Volcanoes (Powell)

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76. Section of Highly Denuded Volcano, Minto Hill, Roxburgshire
77. Diagrammatic Section across the Valley of the Tay, near Dundee
78. View of Mesa Verde and the Sierra el Late, Colorado (Hayden's Re-
port for 1875)

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Wind Erosion: Table-Mountains, etc., of the Sahara (Mission de
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Wind Erosion: Harder Beds amongst inclined Cretaceous Strata,
Libyan Desert (J. Walther).

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Wind Erosion: Stages in the Erosion and Reduction of a Table-
mountain (J. Walther)

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82. Manganese Concretions weathered out of Sandstone, Arabah Mountains, Sinai Peninsula (J. Walther).

83. Formation of Sand-dunes

85. Longitudinal Sections of Lake-basins on a true scale

87. Sea-cliff cut in Strata dipping Inland

88. Sea-cliff cut in Strata dipping Seaward 89. Sea-cliff cut in Beds dipping Seaward

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FULL-PAGE PLATES

Plate I. Joints in Granite, Glen Eunach, Cairngorm (from a photograph by W. E. Carnegie Dickson)

Plate II. Weathering of Joints in Granite, Cairngorm Mountains (from a

photograph by W. E. Carnegie Dickson)

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EARTH SCULPTURE

CHAPTER I

INTRODUCTORY

EARLY VIEWS AS TO ORIGIN OF SURFACE-FEATURES-ROCKS AND ROCK-STRUCTURES-ARCHITECTURE OF THE EARTH'S CRUST -GENERAL EVIDENCE OF ROCK-REMOVAL.

HEN geologists began to inquire into the origin of surface-features, they were at first led to believe that the more striking and prominent of these had come into existence under the operation of forces which had long ago ceased to affect the earth's crust to any marked extent. It is not, hard to understand how this conception arose. The earlier observers could not fail to be impressed by the evidence of former crustal disturbances which almost everywhere. stared them in the face. Here they saw mountains built up of strangely fractured, contorted, and jumbled rock-masses; there, again, they encountered the relics of vast volcanic eruptions in regions now practically free from earth-throes of any kind. In one place. ancient land-surfaces were seen intercalated at inter

vals among great successions of marine strata; in other places, limestones, evidently of oceanic origin, were found entering into the framework of lofty mountains far removed from any sea. It was these and similar striking contrasts between the present and the past which doubtless induced the belief that the earth's crust, after having passed through many revolutions more or less catastrophic in character, had at last become approximately stable-the occasional earthquakes and volcanic disturbances of recent times being looked upon as only the final manifestations of those forces which in earlier ages had been mainly instrumental in producing the varied configuration of the land. Mountains and valleys belonged to earth's Sturm und Drang period. That wild time had passed away, and now old age, with its lethargy and repose, had supervened. The tumultuous accumulations of stony clay, blocks and boulders, gravel and sand that overspread extensive areas in temperate latitudes were believed to be the relics of the last great catastrophe which had affected the earth's surface. Some notable disturbance of the crust, it was thought, had caused the waters of northern seas to rush in devastating waves across the land. When these diluvial waters finally retired, then the modern era began an era characterised by the more equable operation of nature's forces.

But with increased knowledge these views gradually became modified. Eventually, it was recognised that no hard-and-fast line separates past and present.

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