Geological Society. 315 



the superincumbent mass, the resulting fissures in this mass may then 

 become matters of calculation. According to Mr. Hopkins, recti- 

 linear lines of dislocation will give rise to a set of longitudinal pa- 

 rallel fissures, and simultaneously to others precisely at right angles 

 to them ; whereas in conical elevations, the fissures will diverge 

 from a centre. If the general axis of elevation be curvilinear, the 

 longitudinal fissures preserving their parallelism with it will be also 

 curvilinear, while the transverse fissures being perpendicular to the 

 former at their points of intersection will no longer be parallel. 



To return from this digression, I must now recall your attention 

 to other papers relating to the carboniferous deposits of England. 

 The coal-measures of the north-western coast of Cumberland have 

 been examined by Prof. Sedgwick and Mr. Williamson Peile, who 

 have described the Whitehaven and other fields in great detail, il- 

 lustrating their account with a map and sections*. The recorded 

 observations in numerous sinkings and borings, both in relation to 

 the succession of the strata and to the complicated faults which in- 

 tersect them, would have been involved in hopeless confusion, if 

 they had simply consisted of a statistical collection of facts attested 

 by miners ; but in this paper, Professor Sedgwick, aided by Mr. 

 Peile's practical and scientific knowledge, has compared the different 

 sections and generalized the phaenomena, giving unity and con- 

 sistency to the whole, throwing the strata into distinct groups, and 

 referring the several faults to different movements to which succes- 

 sive periods of time may be assigned. 



In connection with these recent contributions to the history of 

 our carboniferous strata, I am happy to mention the excellent 

 volume lately published by Professor Phillips, forming the se- 

 cond part of his Illustrations of the Geology of Yorkshire. It 

 is almost entirely devoted to a description of the carboniferous 

 or mountain limestone of Yorkshire and the North of England, 

 a subject already admirably treated in some papers read before 

 this Society by Professor Sedgwick, particularly in his account 

 of the carboniferous chain from Penigent to Kirkby Stephenf. 

 As these geologists had separately explored the same ground, it 

 is satisfactory to perceive that the leading divisions which they 

 have proposed for the classification of the mountain limestone 

 and associated strata, agree in every essential point. Mr. Phillips 

 has described the physical geography of the district occupied by 

 these rocks, their lithological character, stratification, jointed struc- 

 ture, and the most remarkable faults which affect them, especially 

 those which have been called the great Penine and Craven faults. 

 He also treats of the trap dykes which cut through the limestone, 

 and discusses the probable epochs of the displacement of the strata, 

 judiciously pointing out the difficulties unavoidably opposed to the 



* [Prof. Sedgwick and Mr. W. Peile's paper was noticed in Lond. and 

 Ediub. Phil. Mag., vol. ix. p. 501.— Edit.] 



t Trans. Gool. Soc. 2nd Series, vol. iv. part 1, p. C9. — 1835. 



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