382 SKY. GEOLOGY. OVERLYING ROCKS. 



The interference of the trap with the strata presents, 

 as I already remarked, every modification that has yet 

 been described. Some of them require a few words, but 

 the greater number will be sufficiently and even better 

 illustrated by the drawings, which have been so selected 

 as to contain the principal details of the whole line of 

 disturbance; the general aspect of larger portions of the 

 coast being given in other sketches taken from a dis- 

 tance where the minor disturbances were invisible/* One 

 of the objects is to show that there is no persistent parallel- 

 ism between the trap and the stratified rocks, and that 

 the occasional regularity of alternation is deceptive ; since 

 by extending the examination we always arrive at some 

 point where that regularity ceases. This fact has often 

 been noticed on a smaller scale ; but there is here a 

 display of the whole arrangement on a scale so magni- 

 ficent and extensive, since it occupies many miles in 

 length x and so free from all chance of error since the 

 sections are as perfect as if made by art, that it would 

 be unpardonable to pass it over. 



The instances of fracture, separation, displacement, 

 flexure, and entanglement, are sufficiently visible in the 

 drawings ; those of irregularity in the stratified disposition 

 of the trap, require a few w r ords. In one case,^ which 

 occurs not far from Holme, there is a bed extending for 

 a great way, surmounted by a parallel series of the secon- 

 dary strata in contact with it ; but on a narrow inspection 

 innumerable veins are seen branching into the strata in 

 every possible direction, illustrating in a very perfect 

 manner the origin of at least -one order of veins. In a 

 second casej three beds of trap can be traced in a 

 parallel direction for a considerable space, separated by 

 the regular strata, when suddenly the whole unite into 

 one mass. Had not this occurrence at length betrayed 

 the true nature of these beds, there would have been no 



* Plate XVII. f Plate XVII. fig. Q. * Ibid. 



