MINE. 



315 



Hiitoey. channel on the west coast ; and the north boundary 

 '"^^ line extending from the south side of the river Tay in 

 Scotland, westward by the south side of the Ochil 

 mountains, to near Dumbarton, upon the river Clyde; 

 within these boundary lines North and South Wales 

 are included. This area is about 960 miles in length, 

 and, on an average, about 150 miles in breadth. \\ ith- 

 in these bounds all the chief coal- fields are found upon 

 which collieries have been established in Britain ; and 

 no coal field of any consequence has been found, either 

 to the north or south of the lines above mentioned, ex- 

 cepting some small patches of thin coals of inferior 

 quality, and the coal field of Brora in Sutherlandshire, 

 Scotland, which is far disjoined from any other coal 

 field. 



When we take a cursory view of this globe of earth, 

 composed of high, wild, and rocky mountains, its nu- 

 merous valleys, rivers, and undulated surface, together 

 with the vast expanse of ocean, we are apt to consider 

 the mountains and rocks as forming a kind of chaos, 

 without regularity or order; but the laborious and pa- 

 tient investigations of mineralogists have shown, that 

 there is in the arrangement of the various rocks, an 

 order and regularity beyond what was, or is, common- 

 ly imagined, a regularity, perfectly consistent with 

 that Infinite wisdom and Almighty power which form- 

 ed the vast, the unbounded system of the universe. It 

 is this regularity in the succession and arrangement of 

 the various rocks, from the Alpine heights to the val- 

 leys and level of the sea, which guides the mineralogist 

 in hi* investigations, when searching for those mine- 

 rals which are so beneficial to man in his state of civi- 

 lized society. 



Mineralogists have divided the rocks which com- 

 pose the globe into four classes, viz. 



ClMifcM- 

 tioaaf 

 rack* ir.d 



lew at the 

 MriM. 



1. Primitive Rocks. 



2. Secondary, or Transition Rocks. 



S. Floetz, or Newer Secondary Rocks. 

 vest Flocu Trap Hocks. 



In the primitive class of rocks, granite, which ge- 

 nerally forms the highest parts of mountain ranges, is 

 reckoned by mineralogists to be the lowest scries of 

 rocks, and upon which all the other rocks rest. 



It is worthy of particular remark, that the four 

 i of rocks before mentioned, lie in regular 

 i, the primitive rocks being the lower series, and 

 the newest floetz trap rocks being the last in succession ; 

 and although the rocks, composing each of the four 

 dassft, may alternate variously with each other, yet the 

 order of the four classes has never been found inverted ; 

 that is, the primitive and secondary rocks have never 

 been found overlying the other two classes of what 

 arc termed newer floetz rocks. 



Clata of Beds of coal have not hitherto been found in the 



rocaa which primitive or transition class, of rocks, but they are 

 found in great abundance in the third class, termed the 

 floetz or newer secondary rocks. Coals are also found in 

 the newest floetz trap formation ; but the coal-fields are 

 not extensive, though they are sometimes of uncom- 

 mon thickness. 



One striking and discriminating mark in these rocks 

 is, that in the primitive class not a vestige of organic 

 remains is to be found, and very tew in the secondary 

 . whereas the strata which compose the coal-fields 

 abound with innumerable impressions and forms, both 

 of animals and vegetables : The whole arrangement of 

 the strata of the coal-fields exhibits a structure and 



2 



< , : i n 



. 



form most distinctly differing from the other classes of Hiitory. 

 rocks, and therefore has been with much propriety \~~f~n. 

 termed by the celebrated Werner, The Independent Coal 

 Formation. 



The strata or rocks which accompany coal are chiefly Strait 

 as follows : which e ' 



1. Sandstone of various hardness and colour, 

 hades of white, grey, and light red. 



2. Slate-clay. 



3. Bituminous shale. 



4. Indurated argillaceous earth or fire-clay. 



5. Argillaceous ironstone. 



6. Greenstone. 



Although the independent coal- formation occupies a 

 great area of Britain, as before mentioned, its continui- 

 ty is frequently interrupted by mountain ranges and 

 rock-formations of very considerable extent, where no 

 coal is to be found ; and even in those districts where 

 there are valuable fields of coal found, the beds of coal 

 do not in general extend over a great district of country, 

 without being interrupted by what is commonly term- 

 ed troubles, or more properly dikes and slips ; hence 

 the difficulties which occur in working coals, and the 

 caution requisite in searching -a district for them. 



The beds which compose the first and second clan 

 of rocks generally lie in a situation forming a great 

 angle with the horizon, being in many cases nearly 

 vertical, whereas the strata composing the coal- forma- 

 tion are commonly found forming a small angle of ele- 

 vation with the horizon, although there are instances 

 of their being absolutely vertical. 



In some coal-fields there is only found one bed of 

 coal, and in others a very great number, varying in 

 thickness from an inch to many feet; it mii!>t, how- 

 ever, be remarked, that those beds of coal which are 

 very thick, have generally thin beds of stone running 

 through them in a horizontal position, forming a num- 

 ber of subordinate beds of coal, lying very close to one 

 another, having however the appearance of one thick 

 bed of coal. 



In order to exhibit in a clear and distinct view, the 

 various strata connected with beds of coal, the thick- 

 net* of the coals, and alternations of the strata betwixt 

 them, the following sections are examples, taken from 

 the chief coal-fields in England and Scotland. 



SECTION of Ike Coal Strata in the Vicinity of NEW- 

 CASTLE. 



No. Nmom at th StnU. 



1. Allutial cow 



1. Urown mnfamf 



3. Cat! 



4. SUtecby 



5. White ikler ssndHMHl 



6. Cool 



7. (irrj mnAftant 



8. Soft ilaie-cUj 



9. Coat 



10. Hard white (later adttoo* 



11. Hard ndHMM 



It. Coal ... 



13. Son fire-clay 



14. Slatty BUKUtone 



15. Coal . . 



16. Dark ilatc-cty 



IT. Coal .... 



18. Hard white 



Carry forward 



10* 



