What is "coal measures"

Coal \Coal\ (k[=o]l), n. [AS. col; akin to D. kool, OHG. chol, cholo, G. kohle, Icel. kol, pl., Sw. kol, Dan. kul; cf. Skr. jval to burn. Cf. Kiln, Collier.]

1. A thoroughly charred, and extinguished or still ignited, fragment from wood or other combustible substance; charcoal.

2. (Min.) A black, or brownish black, solid, combustible substance, dug from beds or veins in the earth to be used for fuel, and consisting, like charcoal, mainly of carbon, but more compact, and often affording, when heated, a large amount of volatile matter. Note: This word is often used adjectively, or as the first part of self-explaining compounds; as, coal-black; coal formation; coal scuttle; coal ship. etc. Note: In England the plural coals is used, for the broken mineral coal burned in grates, etc.; as, to put coals on the fire. In the United States the singular in a collective sense is the customary usage; as, a hod of coal. Age of coal plants. See Age of Acrogens, under Acrogen. Anthracite or Glance coal. See Anthracite. Bituminous coal. See under Bituminous. Blind coal. See under Blind. Brown coal or Brown Lignite. See Lignite. Caking coal, a bituminous coal, which softens and becomes pasty or semi-viscid when heated. On increasing the heat, the volatile products are driven off, and a coherent, grayish black, cellular mass of coke is left. Cannel coal, a very compact bituminous coal, of fine texture and dull luster. See Cannel coal. Coal bed (Geol.), a layer or stratum of mineral coal. Coal breaker, a structure including machines and machinery adapted for crushing, cleansing, and assorting coal. Coal field (Geol.), a region in which deposits of coal occur. Such regions have often a basinlike structure, and are hence called coal basins. See Basin. Coal gas, a variety of carbureted hydrogen, procured from bituminous coal, used in lighting streets, houses, etc., and for cooking and heating. Coal heaver, a man employed in carrying coal, and esp. in putting it in, and discharging it from, ships. Coal measures. (Geol.)

   1. Strata of coal with the attendant rocks.

   2. A subdivision of the carboniferous formation, between the millstone grit below and the Permian formation above, and including nearly all the workable coal beds of the world.

      Coal oil, a general name for mineral oils; petroleum.

      Coal plant (Geol.), one of the remains or impressions of plants found in the strata of the coal formation.

      Coal tar. See in the Vocabulary.

      To haul over the coals, to call to account; to scold or censure. [Colloq.]

      Wood coal. See Lignite.

The Coal Measures is a lithostratigraphical term for the coal-bearing part of the Upper Carboniferous System. The Coal Measures Group consists of the Upper Coal Measures Formation, the Middle Coal Measures Formation and the Lower Coal Measures Formation. The group records the deposition of fluvio-deltaic sediments which consists mainly of clastic rocks ( claystones, shales, siltstones, sandstones, conglomerates) interstratified with the beds of coal. In most places, the Coal Measures are underlain by coarser clastic sequences known as Millstone Grit, of Namurian age. The top of the Coal Measures may be marked by an unconformity, the overlying rocks being Permian or later in age. In some parts of Britain, however, the Coal Measures grade up into mainly coal-barren red beds of late Westphalian and possibly Stephanian age. Within the Pennine Basin these barren measures are now referred to as the Warwickshire Group, from the district where they achieve their thickest development.

The Coal Measures formed during Westphalian and earliest Stephanian times in the European ('Heerlen') chronostratigraphical scheme (which is approximately equivalent to the Middle Pennsylvanian Series of the IUGS global chronostratigraphical scheme).