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. See under Frictional. -- Gearing chain, an endless chain transmitted motion from one sprocket wheel to another. See Illust. of Chain wheel. -- Spur gearing, gearing in which the teeth or cogs are ranged round either the concave or the convex surface (properly the latter) of a cylindrical wheel; -- for transmitting…

and mineral constitution of the globe; structural geology. (b) Of its history as regards rocks, minerals, rivers, valleys, mountains, climates, life, etc.; historical geology. (c) Of the causes and methods by which its structure, features, changes, and conditions have been produced; dynamical geology. See Chart of The…

A kind of candy sweetmeat, or a piece of it; -- called, in full, Gibraltar rock.

ure, in an icelike form; as acetic or carbolic acid. -- Glacial drift (Geol.), earth and rocks which have been transported by moving ice, land ice, or icebergs; bowlder drift. -- Glacial epoch or period (Geol.), a period during which the climate of the modern temperate regions was polar, and ice covered large portion…

To produce glacial effects upon, as in the scoring of rocks, transportation of loose material, etc. Glaciated rocks, rocks whose surfaces have been smoothed, furrowed, or striated, by the action of ice.

of a dark bluish color, related to amphibole. It is characteristic of certain crystalline rocks.

Bearing globules; in geology, used of rocks, and denoting a variety of concretionary structure, where the concretions are isolated globules and evenly distributed through the texture of the rock.

A crystalline rock, consisting, like granite, of quartz, feldspar, and mica, but having these materials, especially the mica, arranged in planes, so that it breaks rather easily into coarse slabs or flags. Hornblende sometimes takes the place of the mica, and it is then called hornblendic or syenitic gneiss. Similar va…

Resembling gneiss; having some of the characteristics of gneiss; -- applied to rocks of an intermediate character between granite and gneiss, or mica slate and gneiss.

The process of packing with waste rock; stowing.

Decomposed rock, usually reddish or ferruginous (owing to oxidized pyrites), forming the upper part of a metallic vein.

small British marine fish (Motella tricirrata); -- called also whistler and three-bearded rockling. [Prov. Eng.]

; -- specifically applied to the Chicago & Alton; Chicago, Burlington & Quincey; Chicago, Rock Island & Pacific; Chicago, Milwaukee & St. Paul; and Chicago & Northwestern, railroads. [U. S.].

A crystalline, granular rock, consisting of quartz, feldspar, and mica, and usually of a whitish, grayish, or flesh-red color. It differs from gneiss in not having the mica in planes, and therefor in being destitute of a schistose structure.

A whitish, granular rock, consisting of feldspar and quartz intimately mixed; -- sometimes called whitestone, and leptynite.

r and delicate fossils, of the genus Graptolites and allied genera, found in the Silurian rocks. They belong to an extinct group (Graptolithina) supposed to be hydroids.

A grayish or greenish compact rock, composed of feldspar and augite, and allied to basalt.

A conglomerate or grit rock, consisting of rounded pebbles sand firmly united together.

e, shore crab (Carcinus menas) of Europe and America; -- in New England locally named joe-rocker. -- Green crop, a crop used for food while in a growing or unripe state, as distingushed from a grain crop, root crop, etc. -- Green diallage. (Min.) (a) Diallage, a variety of pyroxene. (b) Smaragdite. -- Green dragon (…

A name formerly applied rather loosely to certain dark-colored igneous rocks, including diorite, diabase, etc.