MINERALOGY. 



Stognotj. nitc to clay-slate ; and these differences are so striking 

 ^"Y" 1 ' and characteristic, that a long experienced eye can, at 

 a glance from the summit of a mountain, point out with 

 considerable certainty the different formations of which 

 a country is composed. Landscape-painters, by con- 

 founding together all these differences, or by combining 

 them irregularly, fail not only in accuracy, but in giv- 

 ing their work that appearance, which shews, at first 

 glance, that it is not only a copy of nature, but a copy 

 by one who has formed a distinct conception of the 

 most general and particular features of the inequalities 

 observable on the surface of the earth. Some affect to 

 maintain, that the grand features of mountains and 

 plains, are different in different zones. Thus, that in 

 the torrid zone, for example, the shape, cliff's, and other 

 appearances in mountain;, are different from those in 

 the temperate zone. This, however, is a mistake ; for 

 the tame formation in all countries presents similar ex- 

 ternal characters ; and as the great formations are uni- 

 versal, no such differences can exist. It is true, that 

 the blue colour of the heaven, its degree of illumination, 

 the appearance of distant mountain-vapour, the shape 

 of animals, the luxuriance of vegetable*, combined with 

 the features of mountains, will form a particular char- 

 acter for each climate ; but still the aspect of the rocks 

 of the same formation, in whatever country they occur, 

 will be the same. Thus cliff's of granite and mica- 

 slate, have the same appearance in India and Siberia as 

 in Scotland ; and the valleys of the Urals, do not differ 

 in shape and other features from those formed by simi- 

 lar rocks in this neighbourhood. 



Meullife- 7- Metalliferoiu Minerals. Clay-slate is rich in me- 

 nu mi- tals. It contains many of the venigenous formations 

 "nit. that occur in the preceding primitive rocks, as tin, 

 lead, cobalt, and siler. Very considerable metallife- 

 rous beds also frequently occur, and these contain 

 per-pyrites, red copper-ore, copper-green, blue copptr, 

 malachite, iron-pj rite*, magnetic pyrites, glance-cobalt, 

 grey cobalt-ore, arsenic-pyrites, blende and lead-glance. 

 Gold also occur* in this formation, and it is said alio 

 cinnabar. 



G*HT*phi- 8. Geographical distribution. It is very widely ex- 

 cJ dUtrl. tended rock. In this country, it skirts the Highland* 

 **. from Lochlomond by Callender, Comrie, and Dunkcld ; 

 in the whole of that extensive district, resting on and 

 gradually passing into mica-slate ; the same appearances 

 are to be observed in many other quarters in Scotland. 

 On the continent of Europe, it ha* been traced through 

 a great extent of country ; thus it occur* in Saxonr, 

 Bohemia, Silesia, Franconia, Bavaria ; the Alp* of Swit- 

 zerland, Austria, Hungary, and many other part* in 

 Europe. It occur* also in considerable quantity in 

 North America, a* Pennsylvania ; also in immense quan- 

 tity in South America ; thus it is said, that nearly the 

 whole country between Potosi and Lima, is composed 

 of it. In some of the districts above enumerated, tran- 

 sition clay-slate has been confounded with the primi. 

 tive kind. 



V. Primitive Limestone. 



\'r Kalkstein. Werner. 

 Primitive Limestone. Kirtta*. 

 Primitive Limestone. Jameton. 

 Calcaire Primitif. Brochant. 



Ckir.ctcn. Character! This is a simple mountain rock. Its 

 it common colour* are snow, yellowish, greyish, 

 greenish, and reddish white ; it is sometime* also grey,' 

 the newer varieties incline to yellow. Its struc- 



419 



ture is always granular. Those varieties which are as. Geognotjr. 

 sociated with granite and gneiss are generally more cry. '"Y" 1 "*' 

 stalline than those contained in mica-slate and clay- 

 slate ; and, in general, primitive limestone is more cry- 

 stalline than secondary. Werner remarks, that in the 

 oldest members of the series, that is in those contained 

 in granite, the colour of the limestone is pure white, 

 translucent, and coarse granular ; in the newer mem- 

 bers, the colour is less pure, the translucency less con- 

 siderable, and the granular distinct concretions smaller ; 

 and in the newest, the concretions are so small as only 

 to be discoverable by their glimmering lustre. 



2. Imbedded Minerals. It frequently contains acci- Imbedded 

 dental ingredients, and these occur mure frequently in minerals. 

 the older than in the newer members of the series. \Ve 

 shall mention some of these: 1. Quartz. It occurs in 

 massive pieces of greater or less magnitude, and some- 

 time* also in crystals. 2. Mica. It sometimes occurs 

 in such quantity as to give the stone a slaty fracture. 

 These two minerals, namely, quartz and mica, are the 

 most common accidental minerals that occur in primitive 

 limestone. Thone of less frequent occurrence are the 

 following : common hornblende, actynolite, asbest, ser- 

 pentine, augite, talc, steatite, felspar, epidote, tremolite, 

 garnet, calc-spar, slate-spar, and pyrites. 



5. Stralijicaliun. lt occurs more or less distinctly Siritilca- 

 itratified. It was once the opinion, that granular ag-tion. 

 gregated stone*, as primitive linK-stunc, granite, sienite, 



and greenstone, were never stratified. This, however, 

 is a mistake. Primitive limestone also occurs in beds 

 of greater or less magnitude ; sometimes these beds 

 are short and thick, and are then said to form lying 

 masees (liegende Stiicke ; } or the beds are so thick as 

 to form whole mountains, but this latter is a rare oc- 

 curn : 



4. formations. There are several formations of pri- Forma- 

 mitive limestone. Thus it form* one formation in gra- lion*, 

 nite, another in gneiss, a third in mica-dale, and a 

 fourth in clay-slate. It is more abundant in mica- 

 slate lhan in granite or gneiss, or even in clay-state. 



'I^^Bfimu Minerals It frequently contains Metallifc- 

 ores ' it kinds, and these occur often in beds, "> u * mi 



but .11 vein*. The metalliferous beds contain nerij ' 



ores of different kinds, as lead-glance, blende, magne- 

 tic ironstone, magnetic pyrites, auril'erous arsenic-py- 

 rites, and native gold. The veins are very inconsi- 

 derable, and by some mineralogists are said to contain 

 principally manganese. 



6. Several beautiful varieties occur in this country, 

 as in the island* Tirec, Icolmkill, and Skye; also in 

 Pertiishirc, as in Glen Tilt, in Assynt, in the county of 

 Sutherland, and many other places. The promontory 

 of A thus, in the Archipelago, is said to be composed of 

 primitive limestone ; also the Island of Paros, and part 

 of the Appcnines, as about Carrara and Masia, many 

 parts of the Alp* of Switzerland, the Pyrenees, Car- 

 rapalos in Portugal, Bohemia, Saxony, Silesia, and 

 many other parts of the continent of Europe. 



8. Viet The finest statuary marbles are found in UMI. 

 primitive mountains, and also many of the varieties, 

 used in ornamental architecture. 



Primitive (jypsum. Hitherto this rock has not been primitive 

 observed to form masses or beds of considerable extent Gypsum, 

 in primitive mountain*. Nearly the only authentic ex- 

 ample recorded of primitive gypsum, is that given by 

 Daubuiston, who informs us he discovered a bed of it 

 in mica-slate in the valley of Aoste, and near the vil- 

 lage of Cogne. 



