Annual Report on the Geological Survey of Pennsylvania, Volume 3 |
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Allegheny mountain Allegheny river anticlinal axis argillaceous axes Bald Eagle mountain bands base Bear ridge bed of coal belt blue brown Brush mountain Buffalo valley calcareous Chesnut ridge coal basin coal beds coal field coal measures coal seam color conglomerate contains creek denudation deposites district Eagle mountain east eastern eastward elevation explorations exposed extends Fayette county feet in thickness feet thick flank formation VIII formation XI fossiliferous iron Geological Greene county Jack's mountain Laurel hill layers lime limestone lower Mahanoy miles mineral Monongahela moun nearly neighborhood Nittany mountain Nittany valley north-west northern numerous occurs overlying passes Pittsburg places portion primary rocks range red sandstone red shale region sandstone seam of coal shale side slate slaty soft South mountain south-east south-eastern south-west southern stone strata stratum structure summit surface Susquehanna river synclinal tain termination thin tion township traced tract trough upper western westward yellow
Popular passages
Page 104 - It lies,' says JT Hodge, who first described it, 'in large and nearly square masses, the angles of which are more or less rounded off, showing the readiness with which the lime is dissolved out of the rock. By the removal of this ingredient, and the oxidation of the iron in the stratum, it acquires a brown siliceous crust, sometimes thick...
Page 11 - ... margin of the formation, have frequently the character of coarse conglomerates, made up of pebbles derived from a very great variety of rocks, chiefly those which occur at the base or on the sides of the adjacent hills of the South mountain chain.
Page 66 - Geologist, on page 74, of his Third Annual Report : — " The details above presented will serve to show a remarkable regularity in the position of both the coal and the iron ores throughout indeed the whole broad belt of country embraced between the Allegheny mountain and the Chestnut ridge, and from the southern line of the State to the counties of Clearfield and Jefferson. Of the coal there would appear to be at least three seams of moderate dimensions occuring in the lower part of the series...
Page 12 - ... been formed. This lignite occurring sometimes in seams of two or three inches thickness amid dark shales, has been a fertile source of delusion ; some persons having been induced, by the hope of finding valuable coal mines, to expend both time and substance in the search. All the Geological facts produced during the survey of this formation, discountenance the notion that it contains any coal.
Page 103 - A reference to the stratification, as we behold it in the vicinity of Meadville, will tend to convey a tolerably exact conception of the nature of the beds of rock which occupy the 400' of depth below the base of the conglomerate stratum (formation XII) which there caps the hills forming part of the general margin of the coal field. "These hills on the north and south of the town are at their greatest elevation 488...
Page 89 - ... generally free from gritty particles and with a similar layer in the coal next the roof, it has been advantageously used in the manufacture of fine bricks. Above it is the roof coal, consisting of a bed of coal with shale intermixed in numerous thin layers. Towards the bottom this is a band of true coal from one to two feet thick ; the higher layers are generally thin. The coal in this part of the seam, is in itself of good quality, but the expense of separating it from the accompanying slate...
Page 2 - ... it has also a different topography, which when adequately studied, affords oftentimes a valuable clue in tracing its mineral deposits ; while on the one hand, it has its peculiar difficulties that demand much local knowledge to surmount, and on the other features calculated to lead to useful discoveries if familiarly understood. By allotting, therefore, a particular range of country, as far as possible, to each individual in the corps, and restricting his explorations to that alone, until he...
Page 87 - Immediately underlying the Pittsburg coal seam is a bed of limestone of characteristic appearance, and remarkable for the regularity with which it accompanies the coal. It consists of blue and black limestone, in layers from 6 to 10 in number, separated by shale * * * The average thickness of the whole stratum is 25 feet.
Page 18 - Schuylkill, to Lykens' valley ; and the other embraced between the Stony mountain, and a continuation of the Sharp mountain, reaching nearly to the Susquehanna river.
Page 93 - ... and when exposed to the atmosphere are generally covered with copperas, produced by the chemical action upon the sulphuret of iron. Seventy-five feet above the Pittsburg seam occurs the great limestone, the most extensive and valuable calcareous deposit in the valley of the Monongahela, or anywhere else in the western counties of the State ; for the limestone beneath the Pittsburg coal is comparatively thin and of little importance as a source of lime for masonry or agriculture. About...