12 



THE GEOLOGIST. 



Add to all thete natural advantages a very large supply of coal im- 

 portant for G overnment use, some very intelligent masters and over- 

 seers, cheap labour, and easy access along the valleys* to the ports, 

 and you will not wonder that South Wales should be prosperous. 

 There is an Institute for Engineers specially for this coal-field ; and 

 he must be a second-rate man who cannot realize his £800 or £1,000 

 a-year at least by the charge of a set of works. Many of the owners 

 are extremely wealthy, and hospitable too. And somewhere on the 

 northern crop I visited a friend, who is at once magistrate of his dis- 

 trict, lieutenant of a rifle corps, surgeon of a large work, organist, 

 lecturer, a good geologist, and a kind man. 



The north and south borders are called respectively the north and 

 south crops. Along the northern edge the strata lie pretty flat, or 

 gently inclined. They rest upon the terrace of Millstone Grit and 

 the Mountain Limestone precipices overhanging the red sandstone 

 country of Crickhowel and Abergavenny. 



On the southern crop the beds of rock lie at a steep angle, and 

 again from beneath them come out the Millstone Grit and Mountain 

 Limestone of Oxwich and the Mumbles ; or, further west, the great 

 limestone cliffs of Tenby, which of all places is the place to study 

 Mountain Limestone, Old Red Sandstone, and contorted coal-strata. 



There is one more coal-field in Britain, but a poor one, the culm- 

 measures of Devon, only worked for local use ; and it is more than 

 probable that these culms are coal-beds in the Millstone Grit series. 

 Eor in Scotland, of which we have not yet said anything, and 

 where the richest seams are found, not only in their proper beds, 

 above the Millstone Grit, but in it and all through it. Nay, it does 

 not stop here, for in the Lothians and Fifeshire, as indeed is the case 

 in Northumberland, there are coals and coal-shale among the beds of 

 Mountain Limestone, thin layers of this black fuel lying under 

 mountain masses of the limestone rock ; and here and there are coal 

 sandstones, rippled and worm-marked, showing the action of large 

 lakes, or, much more probably, of the tides on the surface only just 

 before occupied by a coal forest. 



Nor is this all, for deeper still, and far below the Mountain Lime- 

 stone, the Scotch coal-beds lie in the Lower Carboniferous strata. The 

 celebrated Burdie House beds of coal and limestone are among these. 



The great quarries of coal sandstone around Edinburgh, from 

 which their fine building stones have been quarried, lie far below the 

 Lowest level of the Mountain Limestone. There is a charming little 

 work — the " Story of a Boulder," told by Archibald Geikie, that gives 

 a clear notion of the Scottish coal-fields in most pleasant and readable 

 style. 



And then for Ireland. We might almost write a chapter on the 

 coal of Ireland as short as Swammerdam's famous chapter " On the 

 Rats of Africa" — "There are no rats in Africa," said the naturalist; 

 and it is all but the same m Ireland. True, there is a patch or two 



* The Crmnlin Viaduct in Taff Yale is a splendid work of art. 



