Description
The Hamilton Group consists of the Mahantango Formation, a dark gray, gray, brown, and olive laminated shale, siltstone, and very fine-grained sandstone or claystone containing marine fossils, overlying the Marcellus Shale, a fissile gray-black to black, thinly laminated, pyritic, carbonaceous thin shale with sparse marine fauna and siderite concretions. The total thickness of the Hamilton Group in Pennsylvania runs approximately 970 feet. In New York State, it thickens from 250 feet near Lake Erie to over 2,500 feet in Ulster and Greene counties, with depths ranging from outcrops to 8,000 feet below the surface of Sullivan County, in the southeastern part of the state.
In the interior lowlands of New York, the Hamilton Group contains the Marcellus, Skaneateles, Ludlowville, and Moscow Formations, in ascending order, with the Tully Limestone above. These units are divided by the Stafford, Centerfield, and Tichenor limestones. In Ontario, Canada, the Hamilton Group formations are, in ascending order, Bell, Rockport Quarry, Arkona, Hungry Hollow, Widder and Ipperwash; the Kettle Point Formation lies unconformably above.
The Mahantango Formation includes the following members, in descending order: Tully argillaceous limestone, Sherman Ridge, Montebello sandstone, Fisher Ridge, Dalmatia, and Turkey Ridge. In south-central Pennsylvania, it includes Clearville, Frame, Chaneysville, and Gander Run Members. Its thickness in Maryland ranges from 600 feet in the west, increasing to 1,200 feet in the east, and approximately 1000 feet thick in central Pennsylvania.
The Marcellus Formation contains a local limestone Purcell Member and Tioga bentonite at the base in eastern Pennsylvania. Its thickness in Maryland ranges from 250 feet in east, increasing to 500 feet in the west, but is only approximately 70 feet thick in central Pennsylvania.
The Hamilton Group, Tioga Metabentonite Bed, and Needmore Shale formerly were designated as the Romney Formation.
Read more about this topic: Hamilton Group
Famous quotes containing the word description:
“Why does philosophy use concepts and why does faith use symbols if both try to express the same ultimate? The answer, of course, is that the relation to the ultimate is not the same in each case. The philosophical relation is in principle a detached description of the basic structure in which the ultimate manifests itself. The relation of faith is in principle an involved expression of concern about the meaning of the ultimate for the faithful.”
—Paul Tillich (1886–1965)
“To give an accurate description of what has never occurred is not merely the proper occupation of the historian, but the inalienable privilege of any man of parts and culture.”
—Oscar Wilde (1854–1900)
“God damnit, why must all those journalists be such sticklers for detail? Why, they’d hold you to an accurate description of the first time you ever made love, expecting you to remember the color of the room and the shape of the windows.”
—Lyndon Baines Johnson (1908–1973)