COAL 



821 



NON-BITUMINOUS VARIETIES. Anthracite. A coal with a sharp-edged, shining, 

 conchoidal fracture, not easily ignited, but when burning it gives out an intense heat, 

 unaccompanied by smoke, and produces but little flame. Often called stone coal. 



Culm. An impure shaly kind of coal, or anthracite shale, as the culmniferous or 

 anthracite shales of Devon. The term is used in Parliamentary returns to signify 

 anthracite. 



Fossil Coke. An American variety, more compact than artificial coke, supposed to 

 be produced by the action of trap rocks on anthracite. 



RECENT COAL. The true coal era is a well-marked one. Geologically it lies be- 

 tween the Old Red Sandstone and the New Red Sandstone rocks. A newer coal is found 

 in the lias at Richmond in Virginia, United States ; and a coal belonging to the Oolites, 

 at Brora in Sutherland, Scotland, and other places. These newer coals are very insig- 

 nificant as compared with the true old coals. 



BROWN COAX. This comparatively recent coal sometimes resembles bituminous 

 coal. Other varieties have a brownish-black colour, with a coal-like lustre. It is 

 called, when it approaches ordinary coal in hardness and appearance, stone coal. 



Lignite. Wood in a process of change ; when it still retains its woody structure, 

 it is called wood or board coal ; when it consists of thin layers, it is termed paper coal, 

 and when soft and earthy it is known as peat coal. 



The relative importance of mineral fuel in various countries, as indicated by the 

 actual coal area and the real production of some of the principal coal-fields, may be 

 understood by a reference to the subjoined Table : 



COAL-FIELDS OP THE UNITED KlKGDOM. 



It will thus be seen how extremely important the coal-fields of the British Islands 

 really are when compared with any others. This is the case, not merely in the total 

 annual production and the proportionate extent of the deposits, but also from the great 

 number of points at which the coal can be advantageously worked. This will be best 

 seen by reference to the Table given at the end of the article. 



The distribution of coal in the United Kingdom is of vast importance to the 

 country. It is spread over largo areas, commencing with Devonshire in the south, 

 and extending to the northern divisions of the great Scotch coal-fields. A careful 

 examination of all these deposits cannot but prove useful. 



DEVONSHIRE. Lignite of Bovey-Heathfield. Lysons, ' Magna Britannia/ informs 

 us that this so-called Bovey coal was worked for use early in the last century ; and 

 Dr. Maton described those beds in 1797 as being from 4 to 16 feet in thickness, 

 alternating with clay, and he stated that the pits were about 80 feet deep, and worked 

 for the supply of a neighbouring pottery. A pottery was established at Ideo in 1772, 

 and one at Bovey Tracey in 1812, both of which were supplied with fuel from those 

 lignite beds. De la Bcche. 



Mr. William Pengelly carefully investigated the Bovey Tracey lignites. The result 

 of his enquiry was ' that the Bovey lignites are the contemporaries of the " Hempstead 

 Beds " in the Isle of Wight, first discovered by the late lamented Edward Forbes 

 in 1852, and described by him in the following year. Though their discoverer always 

 regarded them as Upper Eocene, they have recently been grouped amongst the Lower 

 Miocene.' Professor Hecr, of Zurich, determined forty-five species of plants from this 

 lignite, forty-one of them being decidedly of the Lower Miocene age. 



Bidcford Anthracite. The beds of anthracite stretch across the country from 

 Barnstaplo Bay, by Bideford and Averdiscot, towards Chittlehampton, a distance of 

 about twelve miles and a half. The anthracite is mixed with the black shales of the 

 carbonaceous deposits. 



'The anthracite is mixed with those shales in the manner represented beneath 



