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NECK (O. Eng. hnecca; the word appear...

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Originally appearing in Volume V19, Page 336 of the 1911 Encyclopedia Britannica.
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NECK (O. Eng. hnecca; the word appears in many Teutonic languages; cf. Dutch ride, Ger. Nacken; in O. E. the common word was heals; cf. Ger. Hals), that part of the body which connects the head with the trunk (see ANATOMY: Superficial and Artistic). The word is transferred to many objects resembling this part of the body in shape or function; it is thus applied to an isthmus, or to the narrowest portion of a promontory, to the narrow part of a musical stringed instrument connecting the head and body, as in the violin, or to a narrow pass between mountains, which in the Dutch form nek, appears in place-names in South Africa. In architecture, the " neck " is that part of the capital just above the " astragal," and the term " necking " is applied to the annulet or round, or series of horizontal mouldings, which separates the capital of a column from the plain part or a shaft. In Romanesque work this is sometimes corded. In Geology, the term " neck " is given to the denuded stump of an extinct volcano. Beneath every volcano there are passages of conduits up which the volcanic materials were forced, and after the mass has been levelled by denudation there is always a more or less circular pipe which marks the site of the crater. This pipe, which is filled with consolidated ashes or with crystalline lava, is the characteristic of a volcanic neck. Active volcanoes often stand on the sea-bottom and when the eruption comes to an end the volcano is slowly buried under layers of sediment. In tropical seas the coral animals cover over the submarine volcanoes which rise nearly to the surface and form great reefs of limestone around them. Should elevation take place after long ages the removal of the overlying strata will bring the volcanic mass to light, and in the normal course of things this will suffer denudation exactly like a recent volcano. Many instances of this are furnished by the geological history of the British Isles. In Carboniferous times, for example, before the Coal-measures were deposited, a shallow sea occupied the southern part of Scotland and the north of England. Volcanic activity broke out on the sea-bottom, and many volcanic cones, both small and large, were produced. These have long since been uplifted and the superjacent strata denuded away over a large part of the area which they occupied. In Derbyshire, Fife, the Lothians and the Glasgow district the remains of Carboniferous volcanoes occur in every state of preservation. Some have the conical hills of lavas and ashes well preserved (e.g. Largo Law in Fifeshire) ; others retain only a small part of the original volcanic pile (e.g. Arthur's Seat, Edinburgh; the Binn of Burntisland) and of the larger number nothing remains but the " neck " which shows where once the crater was situated. In regions of former volcanic activity necks are the most persisterlt of all volcanic structures, because the active volcanic magma Is located deep within the earth's crust, and the pipe by which it rigs to the surface is of great length and traverses a great thickness of strata. Many volcanic necks stand on lines of fault. In other cases have fallen down from strata once occupying part of the walls of the crater but now removed by denudation. The lava which rises and flows out from the crater leaves its trace also in the necks. Sometimes it forms thin beds or flows alternating with the tuffs and having the same basin-shaped dip. More commonly it appears as the material filling fissures and pipes, traversing the ashes irregularly or rising as a central plug in the interior of the neck, and sending out branching veins. Occasionally a whole neck is composed of solid crystalline rock representing the last part of the magma which ascended from the underground focus and congealed within the crater. In Mont Pelee, for instance, the last stage of the eruptions of 1902 to 1905 was the protrusion of a great column of solidified lava which rose at one time to a height of 900 ft. above the lip of the crater, but has since crumbled down. The Castle Pock of Edinburgh is a neck occupied by a plug of crystalline basalt. Necks of this kind weather down very slowly and tend to form prominent hills. After the eruptions terminate gases or hot solutions given out by deep-lying masses of molten rock may find a passage upward through the materials occupying the crater, greatly modifying their mineral nature and laying down fresh deposits. A good example of secondary deposits within a volcanic neck is provided by the Cripple Creek mining district of Colorado. The ore-bearing veins are connected with volcanic rocks and part of these occupy a vertical circular pipe which is a typical volcanic neck. A phonolitic breccia, greatly altered, is the principal rock, and is cut by dikes of phonolite, dolerite, &c. The country rock is mostly granite and gneiss, and blocks of these are common in the breccia. A large volcano was built up in Tertiary times on the granite plateau, and has since been almost entirely removed by denudation. The gold ores were carried upwards by currents of hot water derived from the volcanic magma and were deposited along cracks and fissures in the materials which occupied the crater, and also in the surrounding rocks (see VOLCANO). (J. S. F.)
End of Article: NECK (O. Eng. hnecca; the word appears in many Teutonic languages; cf. Dutch ride, Ger. Nacken; in O. E. the common word was heals; cf. Ger. Hals)
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ALEXANDER NECKAM (1157-1217)

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