NATURAL HISTORY OF COMMERCE. 





NATURAL HISTORY OF COMMERCE 



CHAFIER III. 



THE EfFECT OP GEOLOGY ON 1 II K INDUSTRY OP TUB BRITISH 

 PEOPLE. 



Introduction General Physical Geography of England aa dependent 

 on ita Geology Geological Distribution of Mineral Product*. 



THK soils of a country necessarily vary with the varying 

 luituru of the subjacent strata; and to appreciate the 

 influence of the former on the industry of the inhabitants 

 of any particular district, its geology must be carefully 

 studied; for, apart from climatic effects, the constituents 

 of different soils <l>-ti-nniue, to a great extent, the 

 distribution of plants. The attachment of some 

 species of these to certain kinds of rock is illus- 

 . t;iti\ o of the statement. Arenaria Norwegica, Ceras- 

 t in, K alpinum, and Arabia petrcea are confined, in the 

 Shetlands, to serpentine rock ; Orobanche rubra, in 

 In hind, to the basalt; Erica vagana marks, in Cornwall, 

 the course of many metalliferous veins ; and the preva- 

 lence of other species on sandy, clayey, chalky, or cal- 

 careous beds is well known. 



Great Britain presents in its rock-groups an epitome 

 of the geological structure of Europe, if not of the known 

 world, and offers, accordingly, material for the most 

 fruitful and interesting study. Nowhere can better be 

 seen the connection between geological influences and 

 mining, manufacturing, or agricultural industry. At 

 the first glance, a map of England shows that west of a 

 line drawn from the mouth of the Tees on the north- 

 east, to Lyme Regis on the south-west, the chief 

 occupations are mining and manufactures, while 

 east of the same line agriculture is the staple. The 

 I id, pie of the north, too, are distinct from those of the 

 south. 



The intelligent reader will naturally inquire into the 

 causes of these phenomena. We will at once direct 

 attention to them, and offer some generalisations on the 

 geological distribution of the minerals, plants, and 

 animals most useful to man. 



I. General Physical Geography of England aa depen- 

 dent on its Geology. 



The rocks of Great Britain are divided, according to 

 the origin of their present condition, into two great classes 

 and one sub-class viz., aoveoua rocks, formed by the 

 action of water ; igneow rocks, formed by the action of 

 heat ; and nietamorphic rocks, which, originally stratified 

 or ;i(|iieous, have since been changed in their texture by 

 igneous action. 



Igneous and metamorphic rocks comprise only a small 

 proportion of the rocks of England and Wales. In North 

 Wales they appear largely in the counties of Merioneth, 

 Carnarvon, t and Anglesea; and for twenty miles east- 

 ward of St. David's Head igneous rocks are variously 

 distributed. Rocks of these groups constitute the Gram- 

 pians, the South Highlands of Scotland, the Cheviots, 

 and the Malverns ; they occur too in Derbyshire, Worces- 

 tershire, Charnwood Forest, Devon, and Cornwall, whilst 

 the midland, southern, and eastern parts of England are 

 devoid of them. 



Aqueous rocks, constituting by far the greater pro- 

 portion of the rocks of the entire world, form in our 

 island a number of beds arranged in succession one upon 

 the other, each set of beds, or formations, presenting 

 peculiarities which enable the geologist to recognise and 

 place them in a serial order, which order is irreversible. 

 The following table exhibits the series of formations 

 composing the stratified rocks of England : 





Epochs or Periods. Systems. 



TEETIAKT "I 



or > Pliocene 



CAIXOZOIC. ) 



Formations. 

 t Post-Pliocene. 

 . < Newer Pliocene. 

 (Older Pliocene. 



93 N.E. 



Epoch* or Ptriodi. 



TMTumr 



or 

 CAJBOCOIC. 



t m .-. .. 



; .- .' 

 ,:i:,. i... .... 



Spper 

 iddU 

 BMfe 



SECOHDABT 



or 

 MMOZOIC. 



f Chalk. 



I |.>. r ',.-. -Mi-i. 



Triatrio or Nme 



PRIMARY 



or 

 PALEOZOIC. 



'Permian. 



Carboniferous 



Devonian and 

 Sandstone. 



Silurian . 



Cambrian. 



^Laurentian. 



K 



W*ald*n. 



Purbeck. 



Portlasdiaa. 



Kimmeridge Clay. 



Coral Ba. 



Oxford Clay. 



Cornbraah. 



Great Oolite. 



Inferior Oolite. 



Liaa. 



(Keuper. 

 J M MMkdl 

 ) England). 

 V Banter. 



fCoalMeasnrea. 

 , < Millatooe Grit. 

 ( Mountain Limectooo. 



( Upper Silurian. 

 ) Middle Silurian. 

 | Lower Silurian. 

 V Primordial Silurian. 



In the west, in Devon, Cornwall, and in Wales ; in the 

 north-west, in Cumberland; and in the Pennine chain, 

 which stretches from Northumberland to Derbyshire, we 

 have what form the mountain and hilly tracts of Eng- 

 land and Wales ; all of which are composed of palaeozoic 

 rocks, elevated by the disturbances to which they have 

 been subjected. 



If we pass from the older rocks of South Wales and 

 the border counties in an easterly direction, as from the 

 neighbourhood of Gloucester to London, to the newer 

 and less disturbed rocks, we find that they present low 

 undulating grounds and plains of new red sandstone 

 and lias, succeeded by two great escarpments, the edges 

 of table-lands, of no* more than 1,000 feet above the sea, 

 sloping toward the east. The western escarpment, as 

 seen in the Cotswold Hills, is formed by the oolitic, 

 and the eastern by the cretaceous or chalk strata; 

 the tertiary, comprising on the east the London, 

 and on the south the Hampshire basins, overlies the. 

 chalk. 



This physical structure of England is represented in 

 the following generalised section : 

 w. E. 



Chalk Tertiary 

 Wales. Paleozoic Bocks. Cotgwold*. Downs. 



Ffe. 1. 



If we examine the country farther north, say from 

 Snowdon to Flamborough Head, the arrangement of 

 strata will be found very similar to that observed in the 

 line of the southern sections. Thus in the west rise the 

 disturbed paleozoic strata which form the mountain 

 iuu of North Wales; in Flint and Denbigh car- 

 boniferous rocks appear; then in Cheshire, lies the 

 great plain of new red sandstone, from underneath 

 which rise, in Derbyshire, the carboniferous strata, 

 forming the high grounds in that country; these are 

 succeeded by the low escarpment of the mognesian lime- 



