94 PEOF. T. RUPERT JONES — ON COAL. 



Upper Series : sandstones, shales, etc., with 26 coal- 

 seams, more than 3400 feet. 



Pennant-grit : hard, thick-bedded sandstones, and 15 



coal-seams .... 3246 ,, 



Lower Series : shales, ironstones, and 34 coal-seams 450 to 850 ,, 



Millstone -grit. 



The Coal-measures are thus estimated at 7496 feet, or nearly li- 

 mile in thickness, besides the Millstone-grit, and the Carboniferous 

 or Mountain Limestone occupying a still lower position. 



It may be mentioned that in the British Islands the coal may 

 possibly last, for public use, about 600 or 700 years, according 

 to the latest calculations.*' 



7. Extent and Position of the Coal — All the formations I have 

 enumerated are more or less continuous throughout wide regions ; 

 not only in Western Europe, but also elsewhere over the world. 

 Many tracts of " coal-growths " have been of enormous extent, 

 but have been divided in after times by earth-movements, 

 throwing them into ridges and basins by anticlines, synclines, and 

 faults, with intervening spaces. The coal-fields of South and 

 North Wales, the English coal-fields of Somersetshire, Staffordshire, 

 Warwickshire, Leicestershire, Lancashire, Yorkshire, Denbighshire, 

 Northumberland, Durham, etc., the Scotch coal-fields of Edinburgh 

 and Glasgow, and the small Irish coal-fields in Tyrone, Leitrim, 

 Kilkenny, Tipperary, and Cork, are more or less disunited parts of 

 a great whole. So also there are detached coal-fields of Carbon- 

 iferous age in France, Spain, Germany, and Russia, and wide areas 

 in America, China, Australia, etc. 



All the great geological formations contain some deposits of 

 vegetable matter, often in the form of useful coal ; but none equal 

 to that of the palaeozoic Carboniferous series, since which have been 

 slowly deposited the Permian, Triassic, Ehaetic, Jurassic, Cretaceous, 

 and Tertiaiy formations. 



8. Coal under the South of England — The earth -movements, 

 giving rise gradually to mountain-ranges in some districts, and 

 here and there exposing some of the lowest stratified rocks, have 

 lowered others to great depths beneath the later formations, 

 whither they can yet be followed by the scientific research of 

 geologists. Thus, some of the old coal-measures of Western 

 Europe lie deep in the ground, as in Westphalia ; and some come 

 up quite near to the surface, as in Belgium and in the British area. 

 In fact, a great subterranean ridge of crumpled strata reaches from 

 east to west between those two districts, and the folds of those 

 contorted rocks enclose some of the old coal -bearing beds. 



To realize the whole of the conditions belonging to this subject 

 we must (1) revert to the original formation of the coal; and then 

 (2) consider how it has been distributed and re-arranged. 



(1) For our knowledge of what ruled the local occurrence of 

 coal, we owe a great debt to Mr. Pt. A. C. Godwin-Austen, who 

 had studied the geology of the South-western Counties with Sir 



* Hull, in ' Trans. Geol. Soc. Edinburgh,' vol. vi, 1890, p. 79. 



