C.—GEOLOGY 59 
of the rigid block of Craven; in the west by the compacted ridges of 
Denbighshire and the Berwyns ; and on the south by the ragged ribs of 
ancient rock which fringe the Midland barrier of St. George’s Land. 
Towards the east its unknown boundary lies buried beneath thick Permian, 
Trias and Jurassic rocks, where no man has seen or touched the rocks 
below the Carboniferous. This Midland Coalfield Province includes the 
great coalfields of Yorkshire, Derbyshire and Nottinghamshire; of 
Lancashire and Cheshire, and North Staffordshire ; and the lesser fields 
of North Wales, Shropshire, South Staffordshire and Worcestershire, 
Warwickshire, South Derbyshire and Leicestershire : and also the proved 
and probable extensions of these coalfields underneath the Trias. Within 
this Coalfield Province are nearly a thousand working mines, five hundred 
of them each employing more than a hundred men in the winning and 
working of some 120,000,000 tons of coal per year, or more than half the 
total mineral wrought underground in Britain. 
Study of regional structure must begin with notice of the mode of 
accumulation of the local rocks and of the crustal movements which allowed 
their accommodation, but in dealing with so wide an area in an address, 
one cannot do more than mention the distribution and the varying thick- 
ness of the sedimentary groups exposed. For details of their constitution 
and stratigraphy a reference to the Geological Survey Sheet and District 
Memoirs, and for a brief discussion and bibliography the chapters by 
Garwood, Wright and Kendall in the 1929 Handbook of the Geology 
of Great Britain, must suffice. The only further references noted are 
to certain recent contributions not included in that extensive bibliography. 
THE MIpLAND CARBONIFEROUS GEOSYNCLINE. 
At all exposures round the edges of the Midland Province, older beds 
of the Visean overlap with discordant unconformity against a land topo- 
graphy of moderate relief. ‘Tournasian rocks are only recognised in the 
deep trough south of the Craven Fault, where, in Pendle and the Craven 
Lowlands, downward movement began early in the Carboniferous, and 
1 The Geological Survey Publications drawn upon for information herein 
summarised, include those descriptive of 1-in. maps, New Series, Sheets numbered : 
76 Rochdale . ? 1927 126 Nottingham and 
77 Huddersfield . 1928 Newark 1908 
85 Manchester . 1930 137. Oswestry . 3 1928 
86 Glossop . : 1933 138 Wem < : 1924 
96 Liverpool . 3 1923 139 Stafford . 1927 
too Sheffield . : IQI4 141 Derby and Bu rton- 
ro8 Flint é F 1924 on-Trent ‘ 1905 
110. Macclesfield r 1906 142 Melton Mowbray 1909 
112 Chesterfield é 1929 152 Shrewsbury ; 1933 
113 Ollerton . : IgII 153 Wolverhampton. 1929 
121 Wrexham . SIESIG27 154 Lichfield . : 1926 
123 Stoke-on-Trent . 1924 155 Atherstone , I9IO 
125 Derby and Wirks- 156 Leicester . = 1903 
worth . ¢ 1908 158 Birmingham . 1924 
169 Coventry . - 1926 
together with those relating to the parts of 1-in. maps, Old Series, Sheets 
numbered : 53, 60, 61, 72, 73, 80, 81, 82, 87, 88, 89 and 90, which have not 
been recently revised. 
