711 



ENGLAND. 



a^fadCT.^ the upper bed of rock salt lies 42 yards below the sur- 

 '""""Y""^ face, and is 26 yards thick : it is separated from the 

 lower bed by a stratum of argillaceous stone 10 yards 

 thick ; the tower bed has been penetrated to the depth of 

 4O yards ; its breadth is 1+00 yards, and, in one direc- 

 tion, it has been ascertained to extend 1^ mile. Three 

 other beds of rock-salt have been found in another part 

 ot' the county : the uppermost four feet ; the second 12 

 feet thick ; the third has been sunk into 25 yards. 

 Brine springs arc likewise met with at Droitwii-h in Wor- 

 cestershire, in the midst of a similar red sand-stone. The 

 strain here are as follow : from the surface mould, five 

 feet ; marie, 35 feet ; gypsum, 4O feet ; then a river of 

 brine 22 inches ; afterwards gypsum again : and l>clow 

 this, a rock of salt, into which the workmen have bored 

 five feet. 



Cod folds Although, as we have already remarked, the red saiul- 

 lurrounded stone rock cuts off the coal fields in general, yet in some 

 ' " parts of Lancashire and the western counties, detached 



coal fields arc surrounded by it. The greatest quanti- 

 ties of coal, however, in this district, are in Staffordshire, 

 and that part of South Wales that borders on the Bris- 

 tol Channel: all the strata of coal and iron stone in 

 South W.iYs, are deposited in a limestone basin, the 

 form of which is an irregular oval ; in length 100 miles, 

 and where broadest from IS to 20; its greatest breadth 

 is in the counties of Monmouth, Glamorgan, Caermar- 

 then, and Brecon : in Pembrokeshire it is not more than 

 five miles broad. The deepest line in this basin is be- 

 tween Neath in Glamorganshire, and Llanelly in Caer- 

 marthenshire: the uppermost stratum of coal is found 

 here: the utmost depth of this stratum does nnt exceed 

 50 or 60 fathoms. The succeeding strata of coal lie 

 deeper, and are accompanied with parallel strata of iron 

 ore : the lowest strata at the centre range are from 600 

 to 700 fathoms deep. In this basin there are 12 strata 

 of coal, from three to nine feet thick, and eleven others 

 from 18 inches to three feet, making in all 95 feet. The 

 limestone that forms the substratum of this mineral de- 

 position, appears to the surface all along the boundary of 

 the basin, and is supposed to have an underground con- 

 nection from point to point. 



As we approach the south-western counties, the mid- 

 dle district becomes very narrow, the calcareous strata of 

 the low district approaching near the primary and transi- 

 tion rocks. 



The alpine district of England and Wales is formed by 

 an assemblage of lofty mountains, which pass along the 

 western side of the island : the eastern side of the 

 northern range of these mountains, from Cumberland to 

 Derbyshire, is composed of subcrystalline metalliferous 

 limestone, which in many parts is covered with the mill- 

 stone grit, and shale grit, that have been already descri- 

 bed. In the south-west part of Yorkshire, the limestone, 

 for more tlian 20 miles, is covered by the incumbent grits; 

 the mountains of Craven again exhibit it ; and it rests on 

 . slate in Swaledale, at the base of Inglcborough and in 

 other parts adjoining Westmoreland. The mountains of 

 this county and Cumberland are composed principally of 

 grey wacke, flinty slate, roof stone, and porphyry : a i.nv 

 range of granite rock rises near Shap in Westmoreland, 

 Ont found an ^ marble is found in different parts of this county. In 

 in it. this part of the northern range, ores of lead, copper, and 



zinc, are found : in some |rts of Craven, carbonate of 

 lead and galena are raised. The north-west of Lanca- 

 shire, which composes that district called Furness, con- 



Composi- 

 tion of the 

 alpine dis- 

 trict. 



sist.s for the most part of coarse slate and grey wacke : S ututio. 

 red ha-matitc, u very rich and valuable iron ore, is pro- S ^*"Y"^ 

 cured in great abundance in this pail of the country, par- 

 ticularly between Ulvcrstone and Furness Abbey. The 

 southern part of this range consists of the rocks of Der- 

 byshire : these consist of limestone and basaltic amygda- 

 loid : it is supposed that the former rest on slate : there 

 are here three beds of limestone, the depth of which and 

 the basaltic amygdaloid, is upwards of 250 yards ; in 

 some parts a fourth bed of limestone is found, thicker 

 than any of the others. The total depth of all the known 

 Derbyshire strata, including the small portion of Notting- 

 hamshire, which contain the magnesian limestone, 

 1310 yards. In this range there are SO beds of coal, 

 varying in thickness from .six inches to 1 1 feet : the tot;d 

 thickness of coal is 26 yards. Hence it appears, that aa 

 the thickness of the strata of the low district, (as has 

 been already observed,) is about 700 yards, we must 

 sink 1300 yards deeper, to arrive at the limestone in- 

 cumbent on slate rocks, the depth of which, below the 

 stratum of clay, in the valley of the Thames, must con- 

 sequently be about a mile and a quarter. 



As we approach the alpine district on the west side of Compost- 

 England, rocks of a similar class to those in Wales are "" n ot ' 'he 

 met with, but surrounded by die secondary strata of the ^. l lvcrn 

 middle district : the most considerable of these are the 

 Malvern hills, and the Caradoc hills in Shropshire. Ac- 

 cording to Mr Horner, the central parts of the former 

 are principally composed of granitic rock, mixed with 

 horncblende: the lower declivities are covered with 

 limestone and sandstone. The Caradoc and Wrekin 

 hills are composed of a variety of green stone ; some of 

 them contain actynolite: on the sides of these hills are 

 singular beds of claystone, containing cells, flattened as 

 if by pressure since their formation. 



The mountains, on the eastern side of North Wales, Of the 

 are composed of limestone, containing lead and zinc, mountains 

 The limestone is similar to that of the northern range 

 detached coal fields are met with on their lower declivi- 

 ties, in Flintshire am! Denbighshire. The limestone rests 

 on slate, which, as we proceed to the west, is seen rising 

 from under it : in the same direction, mountains, princi- 

 pally composed of grey wacke, flinty slate, and roof slate, 

 are found : veins of quartz, containing copper ore, also 

 occur. Organic remains have been discovered in the 

 slate of North Wales ; it has not been ascertained that 

 any true granite has been found here : in Anglesey 

 there is serpentine, however, which, from its hardness, 

 beauty, and tendency to a crystalline arrangement, 

 may perhaps be regarded as a primary rock. Diallagc, 

 intermixed with steatite, is found in two mountains, on the 

 eastern side of Radnorshire. Rocks composed of cellu- 

 lar claystone, resembling lava, are met with to the m-*t 

 of these mountains, at Llandegley. The north side of 

 Cader Idris, is covered with scattered basaltic columns, 

 composed of porphyritic greenstone: this mountain 

 contains silicious porphyiv in mass, intersected by veins 

 ot quartz ; silicious rchistpsi- porphyry, also intersected 

 by veins of quartz ; argillaceous porphyry in mass; and 

 granite coinpo>ed of quarrz and schorl in ma 



It has already been mentioned, thru limestone is the Qres ; u 

 foundation rock of the great coal formation in South Smith 

 Wales. The principal mineral treasures of the alpine Wale*. 

 districts of Wales, are copper, lead, and slate; and of the 

 less "Vvaled districts, coals and iron stone. 



We .shall now pass to the Devonian range of the al 



in 

 Wales. 



Of Cader 



IdrU. 



