CHAPTER VI.
ECONOMIC.
There is little to add to what has already been said of the economic value of the mountains, and this chapter is hardly more than a regrouping of facts scattered through those that precede.
_Coal._—Possibly some valuable though restricted deposit was overlooked; but it is safe to say that no thick and continuous bed will be found. The Cretaceous sandstones all contain thin and local beds—enough to mark them as coal-bearing rocks—but there are no seams of value. The best outcrop was seen in the bank of the south branch of Lewis Creek where it crosses the upturned edge of the Blue Gate sandstone. The seam has a thickness of four feet only, and is not well disposed for mining.
But if the Cretaceous coals were well developed it is to be doubted if they would ever be used. They could have no local market. They could not be carried to the east or south on account of the cañons. If taken northward they would have to compete with the coal of Castle Valley, which is more convenient and very abundant. If taken westward to the metal mines of Nevada and Western Utah they would be undersold by the more accessible coals found on the headwaters of the Virgin River and Kanab Creek, and even by those of the Kaiparowits Plateau.
The _Gypsum_ and _Building Stones_ of the region need not be described. They are plentiful in many parts of Utah, and however abundant in this remote place can never be in demand.
_Gold, Silver, etc._—Three parties of “prospectors” have at different times made unsuccessful search for metalliferous veins. In the course of my survey I spent more than a month’s time among the crystalline and metamorphic formations of the mountain tops, and although directing my attention constantly to the rocks, did not discover a fissure vein. Combining these negative data with certain theoretic considerations which are set forth in the fourth chapter, I am led to the very confident opinion that the essential conditions for the production of fissure veins have not existed in the Henry Mountains, and hence that there are no valuable deposits of the precious metals. The same theoretic considerations apply to other mountains of the same character, and I venture to predict that gold and silver will not be found in paying quantity in Navajo Mountain, the Sierra la Sal, the Sierra Abajo, the Sierra Carisso, or the Sierra La Lata.
_Agricultural Land._—Bowl Creek, both branches of Lewis Creek, and the south branch of Trachyte Creek can readily be led to tracts of land sufficiently level for farming, and each furnishes enough water to irrigate several hundred acres. It is possible that these tracts will prove useful for farming, but they lie a little too high to be assured of a favorable climate. The lowest has an altitude of 6,000, and the highest of 6,800 feet.
_Grazing Land._—Above the altitude of 7,500 feet there are many tracts of good grass, available for grazing through the greater part of the year but covered by snow in the winter. Below that level there is a greater area of inferior grass, available through the whole year. By using one portion in summer and the other in winter the mountains could be made to give permanent support to a herd of 3,000 or 4,000 cattle. With such overstocking as is often practiced in Utah they may subsist 10,000 animals for one or two years.
_Timber._—The trees worthy to be classed as timber are of three species—fir (_Abies Engelmanni_), Douglass Spruce (_A. Douglasii_), and yellow pine (_Pinus ponderosa_). The pine is the most valuable and the fir the most abundant. The fir grows upon the mountain slopes, above the level of 7,500 feet and forms thick-set forests. The total area which it covers is not far from twenty-five square miles. The spruce mingles with the fir at the lower edges of the forests; and the pine forms a few open groves a little lower down the slopes.
It is to be doubted if the trees will ever be cut. Other timber of the same quality and superior in quantity lies between it and the settlements, and neither railroad nor mine nor town is likely to create a local demand.
Coal, building stone, gypsum, and timber have no value for lack of a market, either present or prospective; gold and silver are not found; and there is little or no land that can be successfully farmed. Only for grazing have the mountains a money value.
INDEX.
Abajo Mountains, 67, 69, 152
Agricultural lands, 152
Alluvial cones and alluviation, 133, 139
Alpine sculpture, 36, 38
Altitudes of peaks and passes, 3, 117
Analogues of the laccolite, 98
Ancient rivers no larger than modern, 133
Antecedent drainage, 143
Arch, Bowl Creek, 45 , Crescent, 44 , Dana, 43 , G, 43 , Maze, 44 , Pulpit, 33, 147
Arches, Forces which produced laccolitic, 87
Aridity favorable to geological examination, 2, 98 of the Colorado Basin in former times, 120
Aubrey Sandstone, 8
Bad-lands, Sculpture of, 120, 140
Bischof, on contraction of igneous rocks in cooling, 76
Blue Gate flexure, 13 Sandstone, 4 Shale, 4
Bonneville, Outlet of Lake, 134
Bowl Creek arch, 45
Cañons of the Colorado as obstructions to travel, 1, 151 as evidence of arid climate, 120
Carboniferous strata, 8
Carriso Mountains, 69, 152
Circle Cliffs, 14
Cleavage, Slaty, not found, 66 , Vertical, produced by sapping, 55
Cliffs, Circle, 14
Climate, Arid, favorable to geological examination, 2, 98 , General influence of, on erosion, 103 , Influence of, on sculpture, 117
Coal, 5, 151
Colorado Basin, History of the, 84 Desert, 134 River, Origin of the, 85
Colors of sandstones, Local variation of, 7
Comminution of detritus aids transportation, 106
Competence, 110
Conditions of rock flexure, 83
Cones, Alluvial, 133
Consequent drainage, 143
Contact phenomena, 65
Contraction of igneous rocks by cooling, 75, 80
Corrasion, 100, 101 , Relation of, to declivity, 112 , to friction of flow, 109 , to transportation, 111
Cover of the laccolites, Depth of the, 86, 94
Crescent arch, 44
Cotta, Prof. Bernhard von, cited, 75
Cretaceous period, Disturbance at the close of the, 10, 85 rock series, 4
Cross-lamination, Inclination of, 7
Dana arch, 43
Declivity, General influence of, upon erosion, 102 of stream beds, relation to corrasion, 112 , relation to transportation, 108 , Relation of, to quantity of water, 113
Declivities, Influence of unequal, on divides, 140
Degradation (see Erosion), 99, 115
Delesse on contraction of igneous rocks in cooling, 76
Densities of igneous rocks, 75 of sedimentary rocks, 77
Density a condition of laccolitic intrusion, 73, 74 of porphyritic trachyte, 77
Denudation (see Erosion), 99, 115 of laccolites, 21
Deposition by running water, 111
Diameters of laccolites, 92
Dike near Mount Ellsworth, 59
Dikes and sheets defined, 20 , Flat-topped, 28 of Mount Ellsworth, 23 of Mount Holmes, 28 , Relation of, to strains, 96
Dinah Creek Pass, 3
Dirty Devil River, Flood-plains of, 131
Distances, Table of, 17
Distribution of laccolites, Horizontal, 20, 30 , Vertical, 21, 56
Divides in bad-lands, Rounding of, 122 , Instability of, 139 , Law of, 116 , Stability of, 138
Drainage lines, Instability of, 125 , Stability of, 124 , Systems of, 124, 143
Dutton, Capt. C. E., on the intrusive rocks, 61
Economic geology, 151
Elk Mountains, 69
Ellen Mount (see Mount Ellen).
Ellsworth Mount (see Mount Ellsworth).
Energy of muddy streams, 108 streams, how measured, 106
Equal action, Principle of, 123
Erosion, Conditions which control, 102 , Influence of climate upon, 103 , Influence of declivity upon, 102
Erosion, Influence of rock texture upon, 103 , Influence of vegetation upon, 104 of Mount Ellsworth, 25 , Principles of, 99 , Processes of, 99
Farming lands, 152
Faults on Mount Ellsworth, 23 Mount Holmes, 28 , Region of, 12, 15
Fish Lake Valley, Structure of, 14
Fissure veins limited in depth, 82 not found in the Henry Mountains, 83, 151
Flaming Gorge Group, 6
Flat-topped dikes, 28
Flexure of rocks, Conditions of, 83
Flood-plain defined, 127
Flow of streams, Friction of, 107, 109
Folds, The Great, 10, 11, 85
Forces which produce laccolitic arches, 87
Form of laccolites, 55
Frost, 104
Friction of flow of streams, 107, 109
Geikie laccolite, 41
Gold and silver, 151
Granite, Eruptive, 70
Graves, Mr. Walter H., 1
Gray Cliff Group, 6
Grazing lands, 152
Heights, 3, 117
Henry, Prof. Joseph, 1
Henry Mountains, Altitudes of the, 2, 117 caused by resistance of trachyte to erosion, 25, 35 , Contributions of the, to the principles of erosion, 99 , Detailed description of the, 22 , Drainage of the, 144 , Economic value of the, 152 , Planation in the, 127, 149 , Relation of vegetation to type of sculpture in the, 118 , Route of travel to the, 14; their structure laccolitic, 19, 53
Henry’s Fork Group, 4
Hillers, Mount (see Mount Hillers).
Hills of planation, 130
Historical note, 66
History of the Colorado Basin, 84
Holmes, Mount (see Mount Holmes).
Holmes, Mr. W. H., on the Elk Mountains, 70 La Lata and Carriso Mountains, 69
Hopkins on the power of currents, 106
Howell laccolite, 34 , Mr. Edwin E., Fossils discovered by, 5; observation of the Henry Mountains, 66; observation of the Navajo Mountain, 69
Hydrostatic equilibrium, Law of, 72
Igneous mountains of the Plateau Province, 67
Igneous rocks, Contraction of, by cooling, 75, 80
Inconsequent drainage, 143
Instability of divides, 139 drainage lines, 125
Interdependence of drainage slopes, 123, 141
Internal structure of laccolites, 55
Intrusive rocks of the Henry Mountains, 59, 61
Isolation of the Henry Mountains, 2, 18
Jerry Butte, 34
Jukes Butte, 46
Jukes, Prof. J. Beete, on prismatic structure, 76
Jura-Trias rock series, 5
Kaibab structure, 11
Laccolite A, 32 B, 32 C, 32 D, 35 E, 41 F, 42 , Geikie, 41 H, 46 , Hillers, 30 , History of the, 95 , Howell, 34 , Jukes, 46 , Marvine, 42 , Newberry, 41 of Mount Ellsworth, 27 of Mount Pennell, 36 of the western base of Mount Ellen, 40 , Peale, 47 , Possible analogues of the, 98 , Scrope, 47 , Sentinel, 38 , Shoulder, 42 , Steward, 32 , The, defined, 19
Laccolites, Age of the, discussed, 84 , Composite, 55 , Denudation of, 21 , Depth of cover of, 86, 94 , Detailed description of, 22 , Diameters of, 92 , Form of, 55, 91 , Holmes, 27 , Horizontal, distribution of, 20 intruded in soft beds, 58 , Limital area of, 90, 97 thickness of, 91 , Material of, 59 not prismatic, 55 of the Elk Mountains, 70 of other regions, 97; size limited, 86 subsequent to the strata which inclose them, 51 , Vertical distribution of, 21, 56, 65
Laccolitic mountains of the Plateau Province, 67, 69 structure characteristic of the Henry Mountains, 19, 53 Sierra La Sal, etc., 69 conditioned by densities, 74 correlated with acidic lavas, 71 , Discussion of the origin of, 72
Lake Bonneville, Outlet of, 134 , Great Salt, Outlet of, 134 Winipeg, Origin of, 126
Land, Agricultural, 152 , Grazing, 152 sculpture, Principles of, 99, 115 , Timber, 152
La Lata Mountains, 68, 69, 152
La Sal Mountains, 68, 69, 152
Law of divides, 116 , Exception to the, 122
Lewis Creek plain, 128
Limital area of laccolites, 90, 97 thickness of laccolites, 91
Load, Relation of, to comminution, 107
Mallet, Robert, C. E., on contraction of igneous rocks in cooling, 76
Marvine laccolite, 42
Ma-suk’ Plateau, 13 Sandstone, 4 Shale, 4
Maze arch, 44
Metamorphism in the Henry Mountains, 65 on Mount Ellen, 38 Ellsworth, 24 Hillers, 31 Holmes, 28
Minerals of the Henry Mountains, 61, 64
Monoclinal shifting, 135, 140
Mount Ellen, Character of sculpture of, 118 , Drainage of, 148 , Structure of, 38 , Topography of, 3 , Vegetation of, 118 Ellsworth, Character of sculpture of, 25, 118 , Drainage of, 145 , Stereogram of, 23, 95 , Structure of, 22 , Topography of, 3 , Vegetation of, 118 Hillers, Character of sculpture of, 119 , Drainage of, 147 , Structure of, 30 , Topography of, 3 , Vegetation of, 118 Holmes, Character of sculpture of, 118 , Drainage of, 146 , Structure of, 27 , Topography of, 3
Mount Holmes, Vegetation of, 118 Pennell, Character of sculpture of, 119 , Drainage of, 148 , Structure of, 35 , Topography of, 3 , Vegetation of, 118
Mount Taylor, 71
Mud-cracks, Fossil, 9
Navajo Mountain, 69, 152
Newberry, Dr. J. S., on the Sierra Abajo, 67 La Sal, 68 laccolite, 41
Oblique lamination, Inclination of, 7
Peale, Dr. A. C., on igneous mountains of Colorado, 69 on the Elk Mountains, 70
Peale laccolite, 47
Pennell, Mount (see Mount Pennell).
Pennellen Pass, 3
Pine Alcove Creek, Former course of, 130
Planation, 126, 139 , Hills of, 130
Plasticity of solids, 82, 83, 97
Plateaus enumerated, 13
Precipitation from running water, 111
Pressure a condition for rock flexure, 81, 83, 96
Prismatic structure, Absence of, 55, 76 defined, 55
Ponding, 125, 139
Porphyritic trachyte, 60, 64
Porphyry; use of term discussed, 63
Powell, Prof. J. W., on the climate of the Colorado Basin, 120
Pulpit arch, 33, 147
Rankine on flexure of beams, 90
Red Gate flexure, 13 , Flood-plains of, 131 , The, 16
Revet-crags defined, 25 of Mount Hillers, 31 of Mount Holmes, 29 of Mount Pennell, 37
Ripple-marks, Fossil, 16
River terraces produced by planation, 132
Rivers, Ancient, no greater than modern, 133
Rock texture, Influence of, on sculpture, 115, 135, 140 , General influence of, on erosion, 103
Rocks of the Henry Mountains, Intrusive, 59, 61 , Sedimentary, 3
Rotation of the earth, 142
Route to the Henry Mountains, 14
San Rafael fold, 16, 18
Scrope laccolite, 47
Sculpture, Alpine, 36, 38 influenced by climate, 117 distribution of divides, 116 rock structure, 115, 135, 140
Sculpture of bad-lands, 120 of Mount Ellsworth, 25 , Principles of, 99, 115
Sentinel Butte, 38
Sheets and dikes defined, 20 of Mount Ellsworth, 24 of Mount Holmes, 28 , Relation of, to strains, 96
Shin-ar’-ump Group, 6
Shoulder laccolite, 42
Sierra Abajo, 67, 69, 152 Carriso, 79, 152 La Lata, 68, 69, 152 La Sal, 68, 69, 152
Solidity of rocks not absolute, 82, 83, 97
Specific gravities (see Densities).
Specimens of Henry Mountain trachyte, 60
Springs; relation to soft strata explained, 82
Stability of divides, 138 of drainage lines, 124
Stereogram, how made, 11, 49 of Mount Ellsworth, 23, 95 of the Henry Mountains, 49 and Waterpocket flexure, 11
Steward laccolite, 32 , Mr. John F., cited, 66
Strains shown by dikes and sheets, 96
Stretching of strata, 80
Structure, Law of, 115
Suncracks, Fossil, 9
Superimposed drainage, 144
Systems of drainage, 124, 143
Table of altitudes, 117 densities of sedimentary rocks, 78 in order of superposition, 79 trachytes, 77 diameters of laccolites, 92 distances, 17 mean densities of certain rock series, 80
Tantalus Creek, 17 , Flood-plains of, 131
Taylor, Mount, 71
Temple Creek, 16 , Flood-plains of, 131
Terraces, River, produced by planation, 132
Tertiary strata protected by lava, 12
Thicknesses of individual strata, 7
Thompson, Prof. A. H., 1, 66
Thousand Lake Mountain, View from, 15
Timber land, 152
Trachyte, Porphyritic, 60, 64
Trachytes of the Henry Mountains not vesicular, 51, 64
Transportation, 100, 101 by streams, analyzed, 106 Conditions which determine rate of, 110 favored by comminution of material, 106 declivity, 108 quantity of water, 109 , Relation of, to corrasion, 111
Trend, Absence of, 2, 30, 98
Tu-nunk’ Sandstone, 4 Shale, 4
Unconformities, 8, 85
Unconformity at Salina, 14
Vegetation, General influence of, on erosion, 104
Veins, Absence of fissure, 83, 151 , Fissure, limited in depth, 82
Vermilion Cliff Group, 6
Vertical cleavage by sapping, 55
Volcanoes of the Plateau Province, Extinct, 67, 70
Volume of streams, Influence of, on erosion, 104 transportation, 109 , Relation of, to declivity, 113
Warren, General G. K., on the valley of the Minnesota River, 126
Waterpocket Cañon, 137 flexure, described, 12 , Passes across the, 16
Watersheds (see Divides).
Weathering, 100
White, Dr. C. A.; identification of Henry’s Fork Group, 4
Whitney, Prof J. D., on inclination of bedding, 52
Winipeg, Origin of Lake, 126
Zones of laccolites, 57, 58, 74
[Illustration: Plate I. MAP of the HENRY MOUNTAINS AND VICINITY. Photographed from a model in relief. Triangulation by A. H. Thompson. Topography by W. H. Graves.]
[Illustration: Plate II. STEREOGRAM of the HENRY MOUNTAINS AND WATERPOCKET FOLD. Including the same area as Plate I.]
[Illustration: Plate III. MAP of the HENRY MOUNTAINS. by G. K. Gilbert. Photographed from a model in relief.]
[Illustration: Plate IV. STEREOGRAM of the DISPLACEMENTS of the HENRY MOUNTAINS including the same area as Plate III. The Blue Gate Sandstone is restored so as to exhibit the form it received by the uplift of the laccolitic domes.]
[Illustration: Plate V. MAP of the HENRY MOUNTAINS by G.K. Gilbert. From a model in relief.]
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TRANSCRIBER’S NOTES
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30 degradation, less than one-half degradation, less than one-half has been stripped of its cover has been stripped of its cover of arch-arching of overarching
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