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GLTJMI'FERJS. The first order of the 

 fourth class, Endogens, comprising 

 the grasses, &c. 



GLUTI'NOTTS HAG. Called also the 

 ramper eel, or poisonous ramper. 

 The name assigned to a species of 

 suctorii. "The suctorii, one of 

 which, the glutinous hag, has 

 scarcely any brain." This creature 

 was regarded by Linnaeus as be- 

 longing to the class vermes. 



GLYCE'MERIS. j A transverse bivalve, 



GLYCI'MERIS. ) gaping at both ex- 

 tremities; hinge callous, without 

 tooth. Fossil and recent. 



GLYPTOLE'PIS. (from 7\v7rro<?, carved, 

 and \c7ri?, scale, Gr.) A genus of 

 ichthyolites found in the lower old 

 red sandstone. The characteristic 

 parts of the creature are its scales, 

 these are of great size compared 

 with that of the animal. One 

 specimen, not more than half afoot 

 in length, exhibits scales three- 

 eights of an inch in diameter. In 

 another specimen there are scales 

 a full inch across, and yet the 

 length of the ichthyolite to which 

 they belonged appears not to have 

 exceeded a foot and a half. Each 

 scale consists of a double plate, an 

 inner and an outer. The structure 

 of the inner is not peculiar to the 

 family or the formation ; it is 

 formed of a num'ber of minute 

 concentric circles, crossed by still 

 minuter radiating lines. The outer 

 plate presents an appearance less 

 common. It seems relieved into 

 ridges that drop adown it like 

 sculptured threads, some of them 

 entire, some broken, some straight, 

 some slightly waved; and hence 

 the name given to this ichthyolite. 

 There are several species. Hugh 

 Miller. 



GLYPTO'POMUS. An ichthyolite of the 

 old red sandstone, known also as 

 Platygnathus. 



GNEISS. The name given by the 

 German mineralogists to a schistose 

 or slaty granite, abounding in mica. 



It is a member of the metamorphic 

 rocks. By some geologists, gneiss 

 has been called secondary granite. 

 Granite frequently may be observed 

 passing by scarcely perceptible 

 gradations into gneiss : when 

 granite contains but little felspar, 

 and the proportion of mica is 

 increased, the mica being arranged 

 in layers, it becomes schistose, and 

 we find a true gneiss. Again, when 

 the mica becomes very abundant, 

 gneiss passes into mica-slate. 

 Gneiss occurs in Ireland and Scot- 

 land ; but it is rarely found in 

 England or "Wales. It is most abun- 

 dant in Sweden. Gneiss is com- 

 posed of the same ingredients with 

 granite, namely, felspar, quartz, 

 and mica, its texture being equally 

 crystalline. According to the Hut- 

 tonian theory, the materials com- 

 posing gneiss were originally de- 

 posited from water, but from the 

 influence of subterranean heat, 

 became altered, so as to assume a 

 new texture. The structure of 

 gneiss is always more or less dis- 

 tinctly slaty, when viewed in the 

 mass, although individual layers 

 may possess a granular structure. 

 When this mineral is broken per- 

 pendicularly to the direction of its 

 strata, its fracture has commonly a 

 striped aspect. This rock, though 

 slaty in its structure, is rarely per- 

 fectly fissile. Gneiss, like granite, 

 never contains any fossil remains ; 

 when it occurs with granite, it 

 usually lies immediately over the 

 granite ; or, if the strata be highly 

 inclined, it appears rather to rest 

 against the granite than to be 

 incumbent upon it. Gneiss -is more 

 or less distinctly stratified, and the 

 strata are often inclined to the 

 horizon at a very great angle; 

 indeed, they are sometimes nearly, 

 or quite, vertical. Mountains com- 

 posed of gneiss are seldom so steep 

 as those of granite, and their sum- 

 mits, instead of presenting those 



