nd> 



itone. 



Characters. 



this 



I. Red Sandstone, or Oil Red Sa-itistoite. 



(Elter, rother Sandstein. Werner. 

 Old Red Sandstone. Jamewa. 

 Rothe-todte-liegemle. German Miners. 

 Gres Ancien. Iliubuitton. 

 1. Characters. The predominating colour of 

 rock is reddish-brown ; but some varieties are grey, and 

 others white. It occurs in the form, not only of sandstone, 

 but also of conglomerate and breccia. The grains in 

 the sandstone are principally quartz, with occasional in- 

 termixtures of felspar, flinty slate, and scale* of mica; 

 the roundish and angular masses in the conglomerate and 

 the breccia are frequently of quartz, or of granite, gneiss, 

 mica slate, clay slate, porphyry, sienite, quartz-rock, 

 &c. The basis or ground is generally an iron- shot 

 clay, or it is composed of smaller particle* of quartz or 

 feUpar, as is often the case in the conglomerates and 

 breccias. The basis is sometimes highly impregnated 

 with silica, and then it i very hard ; and, in oilier va- 

 rities, it has a porpliyrilic character. 



\iltwdinate lied* and Veiat. It contains beds and 

 vein* of porphyry ,'sienile, quartz-rock, clay-slate, lime- 

 stone, and various trap-rock', such a amygdaloid, 

 greenstone, basalt, trap tuff, and pitctutone. 



| Petrifie. 3. Pelrifactioni. \ ery few animal remain* occur in 

 this formation, although it frequently alternates with a 

 limestone, which contain* abundance of marine shells, 

 and other similar organic production*. But petrified 

 vegetable* ace not so uncommon, and the** an general. 



: runka and branches of tree* belonging to the mo- 

 iiocotyledonous cla*s, as U proved by their being com- 

 posed of simple longitudinal fibre* without concentric 



rings. 



| Mtuirre- 4. MiiaUiferoM* , Mint rait. The principal metals 

 B110 *- found in this formation are iron, copper, and lead. The 

 iron ore* are the brown and red ; the copper ores, py- 

 rites and blue copper ; and the lead, galena, or lead 

 glance. 



(*ogid* &>*Ml/~Ia Scotland and Ireland it 

 i* observed testing on primitive, and Uamitm rack*. 

 The same arrangement occur* in Germany, and in other 

 riea on the continent of Europe. 

 (i<-ojrai,hicai Jifcrfn6nhQf>. It form* considerable 



V;' t*. 

 lebcdi 

 id vcini. 



Mfc 



ICfOfTipM- , . 



I ditiri- tract* of country in Scotland. 



Uansiftnsi *ed wnd*t*)oe, which is 

 connected with quartz-rock* is often so nearly allied to 

 the present formation, that it is doubtful if they da not 

 Ulong to the sane series. 



Coal Formation. 

 Coal-in laewi, or oomi field.i6A miners. 



1 t-rrain h< 



i forma- 



Terrain a charbon de teiiu OUer French 



(jeologiilt. 



This very intcrening and important formntion con- 

 sisU of a considerable number ot different rorr.s. '1 lie 

 following inay be enumerateil : J. Coal. 2. Slate. 3. 

 Sandstone. 4. Quartz-rock. 5. Limestone, ti. Iron- 

 stone. 7. Clay. 8. Trap. these 

 rocks, the roost frequent are, the sandstone, slate, iron- 

 stone, and coal ; the others, from their comparative ra- 

 itiay be viewed a* subordinate members of the for- 



1. ('<n! Two species of coal are found in this for- 

 matt')ii, viz. hlack coal, and fiance coal, or Hind coal ; 

 the former has a r< Mtre, and is bituminous, 



and burns with much flame and smoke; while the 



VOL. XIV. PART II. 



MINEKALOGY. 425 



other is net bituminous h*s a metallic lustre, and bums 

 without flame and smoke. 



This mincnl, whether black coal, or glance coal, 

 occurs only in beds which vary in thickness from a 

 few inches'tl) several yards ; and" there arc rare instan- 

 ce* ef their attaining a thickness of three hundred leet, 

 as in the vicinity of St. Aubin, in Houergue : but in this 

 case, the coal is disposed rather in enormous imbedded 

 numroo, or kidneys, than in true beds. The thickness 

 of the beds often continues wonderfully regular lor .1 

 great extent; but in others, they contract ami expand, 

 in the line of direction ; o that, in the course ol 

 same bed, the thickness will vary from an inch to se- 

 veral yards. 



2. Slate Under thi" head, we include bituminous Slate, 

 shale, slate-clay, and flinty slate. 



a. Bituminous Shale. This mineral M clay, more or R, luminous 

 less impregnated with coally matter, of a black co- Sh*l. 

 lour, with a slaty fracture, and affording a shining re- 

 sinous streak. It frequently contains impressions of 

 reeds and ferns. It passes into coal, is frequently in- 

 termixed with \f, or alternates in beds often of consi- 

 derable magnitude, with the other rocks of the coal for- 

 mation 



6. Slalf Clay. Thi rock is of a grey, or black co- S | ata city, 

 lour, with a slaty fracture, and tftafAs a grey dull 

 streak. It sometimes contain* scales of mica, and grains 

 of quart/ and tVlspar ; and when the-i- innv.i-e in 

 quantity, it passes into sandstone. It frequently con- 



rexetabte imnretnont, whkrh are principal i- 

 ferns and reeds. Like bituminous shale, it alter- 

 in bed* of Tarious magnitudes, with the other rocks of 

 the coal formation. 



c. Flinlif .SY/r/f.The slate-clay is sometimes highly PllntysUft. 

 impregnate !ic, and th'en it i very hard ami 



looking, and passes into the mineral named Flin- 

 - T. Imlwddcd masses, and beds of flinty 

 occur in the slate-clay, and occasionally associated widi 

 other members of the coal formation. 



^iindHone. The predominating mineral in this Sandstone. 

 sandstone M quartz, in granular concretions, which - 

 variously interminple<l with flinty slate, felspar, i 

 ami portions of different species of rock of the primi- 

 tive specie* ; all of which are generally connected to- 

 gether by a basis or cement of ,i grey-coloured and 

 earth}- aspect. Somrtim. the earthy l>iiW is wanting, 

 when the grains are ioined together, in the same man. 

 ner as in granite, and other rocks of the same decrip- 

 The constituent jwrts are sometimes so large as 

 to form conglomerate? and breccia* : l>ut generally they 

 are small, ttnd when much intermixed with clay, pass 

 into slate-clay ; and then they contain more vegettblb 

 impression* than usual. 



4. Quartz This iiiiii'ra], in the limn of quartz-rock, Quartz. 

 sometimes occurs in be<N. 



5. Limcilone. A grey-coloured compact limestone 

 sometimes occurs in con-iderabU- 1ml., in coal-field*, 

 and alternates with the varioui rock" of the liiriTi.-itic'ii. 

 In some districts the limes lone is abundant ; in ol 



it is rare; and in many it is entirely wanting. It oc- 

 cur* in the coal fields near Edinburgh, and in those 

 in the north of England. 



6. lion Stone. This irorMrtone, WWCB 

 carbonate, sMUttiuiu bydlale of iron, occu 

 alternate with slate-clay, or bituminous 

 disposed in balls and lenticular musses, i 

 larly. or in regular rows in the strata. 



abundant mineral in ino-.t of the coal-fields in Scotland 

 3 H 



ii sometimes Iron-itont. 



that 

 hale, or it is 



ither irregu- 

 It is a very 



