296 
POPULAR SCIENCE REVIEW. 
found in or above those rocks which we now dis- 
tinguish as Permian and New Red Sandstone proper, 
o (With the coal of the Oolitic period, such as occurs 
2 at Brora, in Sutherlandshire, and in some parts of 
| the Continent, or the yet newer coal and lignites of 
5 the Tertiary formations, we have not to deal. These 
« are exceptional conditions, and, as compared with 
0 the old coal, of very small commercial value.) 
7" The coal-fields of Great Britain may be grouped, 
g as shown upon the accompanying map, into — 
1 1. The South Wales, Gloucestershire, and Somer- 
•J setshire fields. 
§ 2. The South and North Staffordshire and Shrop- 
|5 shire fields. 
I 3. The Midland, including the Nottinghamshire, 
| Leicestershire, Warwickshire, Derbyshire, and York - 
« shire coal-fields. 
£ 4. The Lancashire, Cheshire, and North Wales 
® coal-fields. 
§ 5. The Northumberland and Durham coal-field. 
1 6. The coal-fields of Scotland. 
^ These are unquestionably isolated deposits of fossil 
« fuel. Within those divisions there may be, there 
| probably are, connections. The Staffordshire and 
| the Shropshire beds may be found to be in union, 
7s and those grouped as the Midland, — although there 
Hare now wide gaps of country unexplored, — are 
T possibly one field. Prom the Lancashire coal-field, 
h it is not improbable, but an extension of beds may 
~be discovered, passing under Liverpool and the 
g Mersey, uniting the Lancashire with Cheshire and 
| Flintshire fields. Some have supposed that the 
s coal-beds were at one time extended over the whole 
S area of the British isles, and that they have been 
I removed, from the now vacant portions, by denuda- 
| tion. Such a condition is physically impossible, 
£ seeing that immense tracts of land must have been 
-2 required to produce the vast vegetable growth, and 
§ quiet waters, to accelerate the necessary chemical 
« changes in that vegetable matter, upon which the 
| production of coal depends. Such a condition is 
§ geologically improbable, the Carboniferous Lime- 
c stone requiring insular masses, around which the 
=g marine animals, upon which its formation chiefly 
“ depended, did their vast work, slowly, in shallow 
waters, while the Millstone Grit, and all the shales 
"and sandstones, indicate large tracts of country 
