372 



GREAT BRITAIN 



are obtained from these strata. Jurassic strata 

 occur in Scotland at Brora ( Sutherland ), in Skye, 

 &c. In the Brora Oolite a seam of coal 3 feet in 

 thickness has been worked oft' and on since 1820. 

 It is the thickest bed of pure vegetable matter 

 detected in any Mesozoic formation in Britain. 



The Cretaceous System (q.v. ), consisting chiefly 

 of chalk with underlying sands and clays, all very 

 rich in fossil remains, occupies a broad tract to the 

 east of the Jurassic strata, and parallel to them. 

 Beginning a little north of Flamborough Head, the 

 cretaceous strata may be traced through York and 

 Lincoln, then across the Wash into Norfolk, Suffolk, 

 Hertford, Buckingham, Oxford, Berks, to Hamp- 

 shire, where they separate into three arms, the one 

 extending south-westward through Wilts and Dor- 

 set to the south coast ; another taking a south-east 

 direction to Beachy Head ; while the third stretches 

 as a narrow band in an easterly direction through 

 Surrey and North Kent, widening out as it nears 

 the coast, where it occupies the district between 

 Ramsgate and Folkstone. The fresh-water Wealden 

 series, with its abundant remains of reptiles, lishes, 

 shells, and insects, is developed chiefly over the 

 tract that lies between the North and South Downs. 



The Eocene System (q.v.), consisting of clays, 

 sands, and marls, abounding in fossils which ap- 

 parently indicate a subtropical climate, occupies 

 the valley of the Thames, from Hungerford to the 

 sea, and from Canterbury to Saxmunclham, as well 

 as a large district in Dorset, Hants, and Sussex, 

 from Salisbury west to Dorchester, and east almost 

 to Hastings. 



The Oligocene System (q.v.) is very sparingly 

 developed in Britain the only deposits of note 

 occurring in Hampshire and the Isle of Wight. 



The Pliocene System ( q.v. ), consisting of ferrugin- 

 ous shelly sand and marl known as crag, occurs 

 chiefly in Suffolk and Norfolk. The still more 

 recent Pleistocene System (q.v.) is represented 

 by superficial accumulations of alluvium, gravels, 

 boulder-clay or till, bedded clays, &c., which are 

 scattered over wide areas. To the same system 

 belong the cave-deposits with relics and remains of 

 primeval man. 



Minerals. In some respects the most important 

 of British minerals is coal. The greatly-increasing 

 consumption of coal has originated fears as to the 

 possibility of the exhaustion of our mineral fuel (see 

 COAL). Formerly, the only iron produced in the 

 country was obtained from the greensand of the 

 south-east of England, and from the brown hematite 

 of the Dean Forest. The ore was smelted with 

 charcoal. But the introduction of coke and coal 

 for smelting, and the discovery of numerous addi- 

 tional and unthought-of deposits, especially in 

 connection with coal-bearing strata, immensely 

 increased the production of iron, and met the 

 greatly-increased demands for this important metal. 

 In 1760, when charcoal alone was used for smelting, 

 not more than 25,000 tons of iron were produced ; 

 now an average of 4,000,000 or 5,000,000 tons are 

 obtained from some 12,000,000 or 13,000,000 of 

 ore. The most important ore is the ferruginous 

 shale, or impure argillaceous carbonate of iron, 

 found in every British coalfield. The brown and 

 red hematites, associated with the oldest Palaeozoic 

 rocks, yield much metallic iron. Tin is ob- 

 tained from two counties Cornwall and Devon. 

 Copper is obtained from the same two coun- 

 ties, out the quantity obtained in Britain has 

 greatly declined since 1860, and is trifling com- 

 pared with what is smelted from imported 

 ores. Other copper mines are or were in Lanca- 

 shire, Carmarthen, and Anglesey (see COPPER). 

 Lead and Silver are obtained from the same ore 

 from numerous mines in Palaeozoic districts. The 

 most productive English mines are in Northumber- 



land, Durham, Cumberland, Shropshire, Yorkshire, 

 Derbyshire, Cardiganshire, Glamorganshire, and 

 the Isle of Man. Small quantities are obtained 

 in Somerset, Westmorland, Stafford, and Chester. 

 All the Silurian counties of Wales contain mines. 

 The Isle of Man yields much ore. In Scot- 

 land the most productive mines are at Wanlock- 

 head and Leadhills. Zinc is obtained chiefly from 

 Cardigan, Denbighshire, Carnarvon, Flint, Cum- 

 berland, and the Isle of Man. Sulphur Ores (iron 

 pyrites) are raised in different parts of Great 

 Britain. The following minerals are also raised 

 viz. arsenic, manganese, gold, nickel, silver- 

 copper, fluor-spar, and wolfram. Salt occurs chiefly 

 in Cheshire and Ulster. 



The following table shows the minerals raised in 

 the United Kingdom in 1888, with their value at 

 the mines : 



Quantity. ^Miu" 1 " 



Alum clay ( Bauxite ) tons 9,666 4,833 



Alum shale ,, 1,984 248 



Antimony ore cwt. 7J 7 



Arsenic tons 4,624 35,197 



Arsenical pyrites r 5,325 4,240 



Barytes .1 25,191 26,147 



Bog iron ore u 10,927 5,463 



Clays(exceptingordinaryclay). 2,562,792 653,419 



Coal ii 169,935,219 42,971.276 



Cobalt and nickel ore n 152 746 



Copper ore , . 16,132^ 60,980 



Copper precipitate n 418" 6,539 



Fluor-spar ,. 140 153 



Gold ore 3,844 27,300 



Gypsum n 130,082 58,998 



Iron ore .. 14,590,713 3,501,317 



Iron pyrites n 23,507 11,302 



Jet Ib. 2,217 332 



Lead ore tons 51,259 438,383 



Lignite n 971 437 



Manganese ore n 4,342 1,934 



Ochre, umber, &c i. 7,573 13,387 



Oil shale n 2,076,469) K1 o ion 



Petroleum , 35 f 519 > 126 



Phosphate of lime i 22,500 43,312 



Salt 2,305,569 700,829 



Slates and slabs , 471,788 1.057,535 



Stone, &c .... 8,694,697 



Sulphate of strontia i 7.064 3,532 



Tin ore - 14,370 894,665 



Tungstate of soda i 2i 54 



Wolfram i 60 1,625 



Zinc ore 26,408 96,94 



Total values 59,834,997 



The total value of the coal and other minerals 

 raised in the United Kingdom was 40,345,945 

 in 1866, 74,094,638 in 1880, and 69,129,664 in 

 1895. The total value of the metals obtainable by 

 smelting from ores produced in the United King- 

 dom (aluminium, antimony, copper, gold, iron, 

 lead, magnesium, silver, sodium, tin, zinc) in 1887 

 was 12,795,993; in 1895, 11,472,225. 



Physical Geography. The physical features of a 

 country are intimately connected with its geological 

 structure. Thus the Highlands and Southern Up- 

 lands of Scotland are built up chiefly of crystalline 

 schists and the older Palaeozoic strata, while the 

 intervening lowlands of the so-called Central Plain 

 are composed mainly of the younger Palaeozoic 

 rocks and overlying accumulations of superficial 

 deposits. The mountainous tracts of Scotland con- 

 sist therefore of more enduring or less readily eroded 

 materials than the lowlands. Any wide tract of 

 the Highlands (built up largely of crystalline schists 

 and granitic rocks), when viewed from a command- 

 ing position, looks like a tumbled ocean in which 

 the waves appear to be moving in all directions. 

 The mountains are massive, generally round- 

 shouldered and often even flat-topped, while there 

 is no great disparity of height among the dominant 

 points of any individual group. This is the result 

 of denudation, guided and controlled by the petro- 

 logical character and geological structure of the 

 rocks. The mountains are monuments of erosion ; 

 they are the wreck of an old tableland, the upper 



