A Summary Description of the Geology of Pennsylvania, Τόμος 2Geological survey of Pennsylvania, 1892 |
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Άλλες εκδόσεις - Προβολή όλων
A Summary Description of the Geology of Pennsylvania: Upper Silurian and ... J. Peter Lesley,Geological Survey of Pennsylvania Board Δεν υπάρχει διαθέσιμη προεπισκόπηση - 2015 |
Συχνά εμφανιζόμενοι όροι και φράσεις
anticlinal Atrypa Bastard limestone Bedford county beneath Beyrichia Bloomsburg Bloomsburg red shale bluish gray Bossardville limestone bottom carbonate Chert clay Clinton Lower Clinton Upper concealed corals creek Danville dark deposits east exposed Favosites fish formation fossil ore bed fossiliferous furnace gray shales Green shale Hall Halysites hard Huntingdon Huntingdon county impure Iron sandstone Jack's mountain Juniata Juniata county Leperditia alta Lewistown lime shales limestone limestone beds limestone layers limy Lower Helderberg Lower red Lower Salina magnesian mass massive Medina Mifflin county miles mined Montour county Montour ridge Orbisonia Oriskany Oriskany sandstone outcrop Pentamerus Perry county places plate Prof quarry Rhynchonella rock Salina Salina Lower sand sandrock sandy shales shaly shaly limestone shells silicious Silurian slate slope soft species Spirifera stone Stormville strata Stromatopora bed Strophomena surface Susquehanna synclinal Tentaculite thick thin township Tussey mountain valley Variegated shales Water Lime Yellow shale York
Δημοφιλή αποσπάσματα
Σελίδα 730 - It will be noticed that at the bottom, in the middle, and at the top of the Variegated shales are three groups of sandy strata ; the middle one making a decided mark in the topography.
Σελίδα 1427 - Amphigenia found in the Oneonta sandstone of New York may be a fresh-water form, but it occurs in the Montrose sandstone in southern Pennsylvania so far away from the old shore line that fresh-water conditions seem, certainly, improbable. The stratigraphical relations of the fishes have been generally misunderstood. The fishes exist, for the most part, not in the Catskill but midway in the Chemung ; the celebrated Holoptychius bed is the second of the ore beds of the "Mansfield Red" and belongs at...
Σελίδα 1415 - [Attegrippus'] third Venango oil sand, 46 " Seven years ago, Professor White asserted that the first oil-sand is the same with his Lackawaxen and suggested that the Allegrippus might prove to be the same with the Third Venango. There is no room for doubt respecting the accuracy of these surmises. The interval between the sands is not far from what we should expect, for in western Bedford it is not more than 600 feet and the decrease in the upper part of the column continues westward to the last...
Σελίδα 1428 - Stevenson2 in Fayette county ; but these have not been studied and their relations are still unknown. The upper beds of the Pocono become calcareous in southwest Virginia where the mollusks are unquestionably Lower Carboniferous. The plant remains, obtained in Pennsylvania, are for the most part imperfect, but an abundant flora exists near New river in Virginia, which has been collected by Mr. RD Lacoe. It has not been been studied in detail, but enough has been ascertained to show that its facies...
Σελίδα 1413 - No outcrop is seen in the adjoining county of Somerset until the western edge has been reached, where, under the great anticlinal of Laurel Hill, the Youghiogheny river has cut down to the Delaware flags. There the Montrose sandstone is present, but only a few feet thick ; while at not more than three miles further west, on the other side of the anticlinal, the Catskill has disappeared and the Vespertine (Pocono) rests directly on the Montrose shale. The Chemung shows a similar decrease in the same...
Σελίδα 1431 - Cenozoic brought a sufficiency of burdens in the past. General, not circumscribed conditions must be taken as the basis of subdivision of the column. The separation between Lower Carboniferous and the Upper Devonian is too well marked physically as well as palseontologically over an immense area to be ignored for any but the most cogent reasons.
Σελίδα 1426 - ... time, when subsidence did little more than to keep pace with the inflow of sediment, the area nearest to the region of great drainage, whence large streams with rapid flow poured their material into the shallow basin, would show muddy bottoms and muddy, more or less brackish water which would be unfavorable to animal life of Chemung types. As the Appalachian land became narrower southward, the untoward conditions are less marked in that direction. Within the portion of the area lying within southeastern...
Σελίδα 1413 - Chemung a thickness of somewhat more than 1800 feet. The exposures under Laurel Hill in the Youghiogheny and Conemaugh gaps suggest a continuance of the decrease, certainly in the upper portion. The gaps through Chestnut ridge, ten miles west from Laurel, afford the last exposures in this direction of any part of the Devonian on the eastern side of the basin ; the section in the Conemaugh gap,t barely fifty miles in a direct line from Pittsburgh, is ; Ponoco, 443' Montrose red shales, 126' Lackawmcen...
Σελίδα 1412 - Jacksoni is plentiful near the base of the Montrose shales. We have followed this section along practically one line of outcrop for nearly 600 miles, from the northern boundary of Tennessee into southeastern New York. Its persistence, stratigraphically, is remarkable, since variations in structure are inconsiderable until within thirty miles of the New York border; but serious changes of some sort occurred during the long period of deposit, for, in the extreme south, even the representative of the...
Σελίδα 1424 - Catskill, almost wholly red shale and red or greenish gray sandstones, appears to be wholly non-fossiliferous ; but the Chemung carries its fossils to practically the top of the Montrose shales. The condition is unquestionably the same in northern Virginia. Near the Tennessee border the equivalent of the Montrose sandstone has...