318 Prof. Morris — Lead-mines of the North of England. 



Mines is at an elevation of 1400 feet above the sea, Kilhope Law 

 rises 2206, while Crossfell (capped by MiUstone Grit) attains a 

 height of 2901 feet ; Dufton Pike 1575 feet, and the Cheviots 2676 

 feet, the three counties of Northumberland, Cumberland, and Durham 

 meeting at Eampgill Head ; Durham, Yorkshire, and Westmoreland 

 at Cauldron Snout. This elevated district, bounded on the east by 

 the Tyne and Wear Coal-field, and on the west by the Whitehaven 

 field, chiefly consists of the Carboniferous rocks, and presents varied 

 physical features. The Penine chain, of which Crossfell is a part, 

 extends from the borders of Scotland to Derbyshire, and from its 

 westerly trend it forms the watershed, whence on the east side fall 

 the waters of the Tyne, Wear, and the Tees. The country presents 

 a varied aspect ; to the east are broad low plains, succeeded by rolling 

 hills and dreary elevated moors, followed by a more hilly and more 

 rugged district, rising gradually on the east side of the Penine chain, 

 and descending more steeply on the western side. These, together 

 with the character of the rocks, influence the vegetation of the 

 country, as shown by the " basset" of the Great Limestone, which 

 forms almost the boundary of cultivated land and human habitations. 

 Above it (as Mr. Sopwith observes) are more or less brown and 

 dreary moors, and below it the hill-sides present a green surface and 

 flowery meadows. The counties of Northumberland and Durham 

 occupy about 2905 square miles, three quarters of which belong to 

 the Carboniferous strata. 



The geological structure consists of more or less altered aqueous 

 rocks with others of igneous origin, some anterior, some probably 

 contemporaneous, and others posterior to the great mass of the strati- 

 fied rocks. The aqueous include the Silurian, Devonian, Carboni- 

 ferous, Permian, and Triassic. The igneous are Porphyry, and Basalt 

 or Dolerite. The Silurian consists of schists, grits, and slates, altered 

 and much plicated or folded, containing very few fossils, except 

 Graptolites ; it attains an elevation of 1700 feet. The Old Red attains 

 an elevation of 200 to 700 feet, and is about 500 feet thick, yielding 

 a few fishes (HoloptycMus, &c.) ; it is unconformable to the beds 

 below, and conformable to the Carboniferous, of which it forms the 

 base. This unconformity is well seen at Siccar Point, near St. Abb's 

 Head, Berwickshire ; also at other places on the way to Canrobie. 

 The Carboniferous rocks, which are about 7000 feet thick, and occupy 

 three-quarters of the area, include the Tuedian, Scar and Yoredale 

 series. Millstone Grit, and Coal-beds. The Tuedian consists of 

 sandstones, shales, and limestones, sometimes magnesian, but no 

 coal ; it is about lOOO feet thick, with indications of Estuarine condi- 

 tions, and contains remains of plants, shells, Cephalopods, some fish, 

 but neither Crinoids nor Brachiopods. 



With regard to the Carboniferous Limestone, great differences are 

 observed in tracing this deposit from South to North. It is very 

 uniform in the South of England, North and South Wales and in 

 Derbyshire. It is wanting in South Stafford, where the Coal-measures 

 overlie the Silurian rocks, but in Yorkshire a change takes place. 

 A line drawn from Jervaux Abbey, on the Yore, Yorkshire, through 



