MINES 293 



certain quantity of calamine, and a little copper ore. At Ecton, in North Staffordshire, 

 si remarkably rich copper mine was worked in the last century, at the intersection of 

 several veins, in the midst of very contorted beds of grey and black limestone. 



The veins of both the above districts are noted for the beauty of the fluor, calc- 

 spar, and other crystallised minerals accompanying the galena ; and those of Derby- 

 shire, also, for the thinning or partial interruption which they suffer in crossing the 

 1 toadstone,' a rock of igneous origin, which is interstratified with the limestone. 

 Besides the lodes or ' rake-veins,' the less normal forms of repository termed ' flats ' 

 and ' pipe-veins ' yield in both these districts large amounts of ore. 



The third metalliferous district is situated in Flintshire and Denbighshire, counties 

 forming the N.E. part of Wales. Next to Alston Moor this is the most productive ; 

 furnishing annually nearly 6,000 tons of lead, and a certain quantity of calamino. The 

 galena is smelted in reverberatory furnaces, and affords a lead far from rich in silver, 

 which was therefore seldom subjected to cupellation, until the introduction of Pattin- 

 son's process of desilverising. The lodes, coursing E. and W., are intersected by 

 several great cross veins, which may be traced for many miles, and only exceptionally 

 yield ore. None of the lead veins appear to be prolonged into the subjacent slate 

 rocks. At the Orme's Head, cupriferous veins have also been worked in the limestone. 



Mines of galena and calamine have, from a very early period, been worked in the 

 Mendip Hills, to the south of Bristol, but are now almost entirely idle. 



Besides the metallic mines just enumerated, the formation of the metalliferous lime- 

 stone presents, in England, especially in the counties of Northumberland and Cumber- 

 land, seams of coal, generally very thin and anthracitic. Far more important are the 

 red and brown oxides of iron, which this formation yields in vast quantity ; the brown 

 ore in beds and veins in Alston Moor ; haematite of the richest kind, in irregular 

 deposits, near Whitehaven, Cumberland, and at Ulverstone, Lancashire ; in less im- 

 portant repositories in Derbyshire, Flintshire, and on the flanks of the Mendip Hills ; 

 and, lastly, excellent brown peroxide in the upper limestone environing the Forest of 

 Dean, where it occupies a series of devious caverns and holes lying more or less in the 

 same plane. Appearances of the same kind, but on a smaller scale, fringe the southern 

 side of the South Welsh coal-field. 



MlNES OF THE LATER EoCK FORMATIONS. 



The most important mines of what used to be termed, in the earlier days of geology, 

 the Secondary rocks, and perhaps of all mineral formations whatsoever, are those 

 worked in the most ancient strata of that division, in the coal-measures. Since, how- 

 ever, the organic contents of the rocks have been more fully studied and compared, 

 the coal-measures have been classed with the Palaeozoic systems, and that supposed 

 line of demarcation between them and the older strata already treated of, can only be 

 retained as a matter of convenience, and as marking in most countries a great change 

 in the character of the mineral contents as we ascend in the geological scale. 



The British islands, France and Germany, frequently present ranges of the older 

 rocks, upon the flanks of which, sometimes unconformably, repose the deposits of coal. 

 The principal of these have become great centres of manufacture; for Newcastle, 

 Birmingham, Glasgow, Sheffield, St. Etienne, &c., owe their prosperity and their 

 rapid enlargement to the coal raised as it were at their gates in enormous quantities. 

 Lancashire, Wales, Belgium, and Silesia, owe equally to their extensive collieries^ a 

 great portion of their activity, their wealth, and their population. Other coal dis- 

 tricts, less rich, or mined on a, less extensive scale, have procured for their inhabitants 

 less distinguished, but by no means inconsiderable, advantages ; such, for example, in 

 Great Britain, are Derbyshire, Cheshire, Shropshire, Warwickshire, the environs of 

 Bristol, &c. ; some parts of Ireland; in France, Litry, department of Calvados, 

 Comanteric, Alais, le Creuzot, &c. ; in Ehine Prussia, Saarbruck, and Westphalia ; 

 and several localities in Saxony, Bohemia, Spain, Portugal, the United States, &c. 



We need not enter here into ampler details on coal mines ; these particulars are 

 given in the article COAL. 



Nature has frequently deposited close to the coal, an ore, whose intrinsic value alone 

 is very small, but whose abundance in the neighbourhood of fuel becomes extremely 

 precious to man ; we allude to the clay-ironstone of the coal-measures. It is ex- 

 tracted in enormous quantities from the coal-fields of Scotland, Yorkshire, Stafford- 

 shire, Shropshire, and South Wales. Much of it is also raised from the coal-strata of 

 Silesia and of Westphalia, but few coal-fields appear to be entirely deficient of it. 

 The iron works of England, which are supplied in great part from this ironstone 

 reduced with coke or coal, pour annually into commerce six millions and a half 

 tons of pig iron. 



The shale, or slate-clay, of the coal-measuros contains sometimes a very large quan. 



