G R A 



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G R A 



highest point at which granite has 

 been discovered in any part of the 

 world is Mont Blanc, 15,683 feet 

 above the level of the ocean. Saus- 

 sure, who has published an account 

 of his ascent of Mont Blanc, infers 

 from his observations that the 

 verticals beds of granite were origi- 

 nally horizontal and have been 

 upheaved by some violent convul- 

 sions of nature, and he states that 

 what now forms the summit of the 

 mountain must at some former 

 period have been more than two 

 leagues below the surface. 



GRA'NITEL. j A name given by 



GRA'NITELL. j Kirwan to a bi- 

 nary aggregate composed of any 

 two of the following ingredients : 

 felspar, mica, shorl, quartz, garnet, 

 steatite, hornblende, jade. 



GRANI'TIC AGGREGATE. A granular 

 compound, consisting of two, three, 

 or four simple minerals, among 

 which only one of the essential 

 ingredients of granite is present. 

 Among the granitic aggregates, 

 which contain only one of the 

 essential ingredients of granite, 

 may be enumerated combinations 

 of quartz and hornblende, quartz 

 and actinolite, felspar and schorl, 

 mica and hornblende, quartz, 

 hornblende, epidote, &c. &c. 



GRANITI'FEROUS. All rocks admit of 

 a twofold division, namely, into 

 the primary or granitiferous, and 

 the secondary or derivative classes. 

 The granitiferous rocks comprise 

 various series of massive and 

 schistose rocks, which are not 

 fragmentary, nor fossiliferous, and 

 which are always inferior, in their 

 original position, to those of the 

 secondary class. Boase. 



GRA'NITINE. An aggregate of three 

 mineral constituents, one or more 

 differing from those which compose 

 granite. For example, an aggre- 

 gate of quartz, felspar, and shorl 

 is a granitine, as is one of quartz, 

 mica, and shorl ; or quartz, horn- 



blende and garnet; and many 

 others. 



GRANI' VOROTJS. (from granum and voro, 

 Lat.) Eating grain ; subsisting 

 on grain. 



GRA'NULAR LIMESTONE. A subspecies 

 of carbonate of lime, the result of 

 a confused or irregular crystalliza- 

 tion. Structure foliated and gran- 

 ular. The grains are of various 

 sizes, from coarse to very fine, 

 sometimes, indeed, so fine that the 

 mass appears almost compact. When 

 these grains are white and of a 

 moderate size, this mineral strongly 

 resembles white sugar in solid 

 masses. Its fracture is foliated, 

 and when the structure is very 

 finely granular, the fracture often 

 becomes a little splintery. It is 

 more or less translucent, but in the 

 dark-coloured varieties, at the ed- 

 ges only. Its colour is most com- 

 monly white or gray, often snow- 

 white, and sometimes grayish black. 

 Some varieties are flexible when 

 sawn into thin slabs. Granular 

 limestone is sometimes a pure car- 

 bonate of lime. It occurs in very 

 large masses, and is almost exclu- 

 sively found in primary rocks; 

 sometimes it occurs among second- 

 ary, but then its relative age is 

 easily determined by the shells it 

 contains, or the accompanying min- 

 erals. In the Pyrenees vertical 

 beds of granular limestone alternate 

 with granite and trap, or the 

 limestone is sometimes intermixed 

 with those rocks. 



There are few countries in which 

 granular limestone is not found. 

 Italy and Greece furnished the 

 ancients with valuable quarries. 

 Both granular and compact lime- 

 stone furnish numerous varieties of 

 marbles, but those which belong to 

 the former exhibit a more uniform 

 colour, are generally susceptible of 

 a higher polish, and are consequenty 

 most esteemed for statuary and 

 other purposes. 



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