TRANSACTIONS OF THE SECTIONS. 657 



land, and Northumberland, as far as the valley of the South 

 Tyne; so as to constitute one great elevated geological area, 

 bounded on the north by a dislocation, varying in amount from 

 600 to 1200 and 2000 feet, which ranges in general E. and W.; 

 on the west by the great Cross Fell fault, of at least 3000 or 4000 

 feet, ranging S. by E., from Brampton to near Kirby Lonsdale; 

 and on the south by the double Craven fault, of 1000 to 3000 

 feet, which goes to the E.S.E. 



Within this area numerous mineral veins are found, princi- 

 pally running E. and W., or parallel to the northern boundary, 

 comparatively few productive veins being found passingN.and S., 

 though dislocations and rock dykes of importance, and a great 

 proportion of the leading fissures, take the direction N.N.W., 

 which is nearly parallel to the great Cross Fell fault. 



This east and west tendency of the veins is conspicuous in all 

 the northern mining tracts of the Tyne, Wear, Tees, and Swale ; 

 it is less predominant in the southern mining fields in Wharf- 

 dale and Niddersdale, which are near to the E.S.E. fault in 

 Craven. That fault is remarkable for its double line of disloca- 

 tion ; and for the coincidence of its direction with the most con^ 

 tinuous divisional planes of the slate, with one parallel dyke of 

 greenstone, and one or more bands (veins) of pyritous slate. 



There is therefore in this great tract of country a clear gene- 

 ral analogy in direction between the lines of convulsive move- 

 ments, mineral veins, and open or sparry fissures. The fissures, 

 joints, and cracks often display in their contents, and circum- 

 stances of arrangement, a close affinity to metalliferous veins ; 

 and the whole investigation appears to indicate among them all 

 a common and fundamental relation. Professor Phillips is of 

 opinion that the definite direction of the joints and fissures is 

 one of the facts to be most attended to in a theoretical point of 

 view, since it appears extremely probable that this character 

 of joints is the primaiy phaenomenon which, by presenting 

 lines of least resistance to the disturbing forces concerned, has 

 permitted the dislocations to follow certain principal parallels. 

 The agencies whereby not only the slip veins, but often the un- 

 disturbed fissures, joints, cracks, and hollows in rocks, and 

 insulated cavities in shells, have received their metallic or sparry 

 contents, constitute a really distinct branch of inquiry, though 

 it is already evident that the solution of either problem cannot 

 be effected without unfolding common principles of symmetrical 

 aggregation, and chemical and electrical action not yet familiar 

 to geologists. 



1834. 2 u 



