Annual Report on the Geological Survey of Pennsylvania, Volumes 1-6

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Page 177 - FAULT, in the language of miners, is the sudden interruption of the continuity of strata in the same plane, accompanied by a crack or fissure varying in width from a mere line to several feet, which is generally filled with broken stone, clay, &c., and such a displacement that the separated portions of the once continuous strata occupy different levels.
Page 176 - Trap family, usually fissile. It is sonorous when struck with a hammer, whence its name. Coal Formation. — This term is generally understood to mean the same as the Coal Measures. There are, however,
Page 92 - PYRITES (Iron). A compound of sulphur and iron, found usually in yellow shining crystals like brass, and in almost every rock stratified and unstratified. The shining metallic bodies, so often seen in common roofing slate, are a familiar example of the mineral. The word is Greek, and comes from irvp, pyr, fire, because, under particular circumstances, the stone produces spontaneous heat and even inflammation.
Page 91 - Grit, a provincial name for a coarse-grained sandstone. Gypsum, a mineral composed of lime and sulphuric acid, hence called also sulphate of lime. Plaster and stucco are obtained by exposing gypsum to a strong heat. It is found so abundantly near Paris, that Paris plaster is a common term in this country for the white powder of which casts are made.
Page 90 - DILUVIUM. Those accumulations of gravel and loose materials which, by some geologists, are said to have been produced by the action of a diluvian wave or deluge sweeping over the surface of the earth.
Page 30 - Philadelphia with the beautiful article employed in so many of its public and private edifices. It is on the farm of Mr. John R. Thomas. The beds on this quarry are slightly contorted. The portion worked for the marble separates into two bands. The rock occurs in massive beds, chiefly white, with sometimes a bluish tinge, and is quarried with great facility. It has been much used in the construction of the Girard College and other public buildings which adorn Philadelphia and the neighboring towns.
Page 34 - Limestone formation, a material is procured, which answers well the ordinary purposes of black paint. This appears to be simply a more than usually carbonaceous, black and soft variety of the slate, occurring near the base of the formation a little above its contact with the Limestone. It occurs also further east on the Bushiill, and has been found likewise on the Union canal, in a corresponding situation in the stratum.
Page 93 - Low hills which skirt or lie at the foot of the great chain of the Apennines in Italy. The term Subapennine is applied geologically to a series of strata of the Older Pliocene period. SYENITE. A kind of granite, so called because it was brought...
Page 175 - If a range of hills, or valley, be composed of strata, which on the two sides dip in opposite directions, the imaginary line that lies between them, towards which the strata on each side rise, is called the anticlinal axis.

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