Geology of CoaLbrook Dale. 



455 



tains, in the course of its range towards Arleston, and at the distance of about 

 a mile from its first appearance, a vertical change of level of about 100 feet. 

 Numerous other instances might be adduced ; sometimes, however, a fault 

 will thin off at each extremity in a simple fracture, as in fault 19, PI. XXXV,, 

 which ranges about half a mile, and produces a ditference of level amounting 

 to 30 feet in the centre of its course. 



In the Old Park, (Map, Plate XXXV. fault 33.) is a series of four of such 

 faults, in parallel and consecutive planes, one fault commencing at a point in 

 one plane corresponding to that where another fault ended hi the adjoining- 

 plane. The maximum effect of one of these faults is about 24 feet, and 

 the range of the whole amounts to nearly three quarters of a mile (see Map). 

 At Wrockadine Wood, two faults cross at an angle of bb"*, and the disturbance 

 of both amounts, at a few hundred feet from this spot, to 25 feet; but at the 

 point of intersection the faults diminish to mere fractures, which do not affect 

 the level of the strata. 



Some of the small slips extend but a *^- 



few yards and produce only 1, 2, or 3 feet 

 of vertical disturbance. These minor dis- 

 locations are so numerous that it would 

 be almost impossible to lay them down. 

 In the map, therefore, I have represented 

 only those which have not less than 20 feet 



The annexed plan of a small district 

 between the Boundary and the Ketley 

 faults exhibits, however, the ramifications 

 of the whole system of fractures. It is a 

 solitary instance of apian of all the minor 

 faults carefully and minutely laid down 

 by a ground-bailiff, Mr. Jones, of New 

 Hadley. The numbers refer to yards, de- 

 noting the amount of disturbance, and are 

 placed on the side of the highest level. 



Thus 1.0 or 0.2 denote that the 

 fault at its point of junction with a larger 

 one produces a difference of level of one 

 or two yards, gradually decreasing as it 

 recedes from that point to zero. 



All the large and main faults also vary 

 greatly in the course of short distances. 



Near Woombrid£:e church the 



