494 



J. Prestwich, Esq., on the 



List of the Faults producing a vertical difference of 20 feet or more, in the Coalbrook Dale District. 



(D.) 



In the first column are given the numbers of the Faults as indicated in the Map, or the first letters of those which are 

 designated by names. In the second column the names without an asterisk are those applied to some of the larger 

 Faidts by the people in the country ; those with an asterisk have been proposed by the author. The headings explain 

 the nature of the 3rd, 4th, 5th, and 6th columns. In the 7th the connexion of the difl^erent Faults is given. Thus, 

 opposite Fault 5, — 4, V. 8, signify that the Fault, Number 5, is connected at one extremity with Fault 4, and at the 

 other with Fault 8. In the same way ranging with Fault 2 is, Trap II. 3, or Fault 2, abuts against Trap at one end 

 and joins Fault 3 at the other. Again, opposite Randley Fault, o, Ra, g, express that the Randley Fault, Ra, at one 

 extremity gradually thins out o, and at the other is connected with the great east Fault g. In the next instance tlie 

 case is more complex. Opposite the Lilleshall Fault is the expression, b, k, •;> I, — /, g, > x, which means that the 

 Boundary Fault b and Ketley Fault k unite or merge > into the Lilleshall Fault I ; and that the Lillesliall Fault (I) at 

 the other extremity, and the great east Fault (g) unite and extend to an unknown distance x. Where o occurs on 

 each of the Roman numerals the Fault thins out at each extremity as o, XII. o. Lastly x, LXIII. x, mean that the 

 fault extends indefinitely. 



NAME. 



Average 

 Amount of 

 Disturbance, 



Direction. 



A seer, 

 tained 

 Extent 

 of range. 



Side of 

 Highest 

 Level. 



Lilleshall+ ... 

 Great East+. 



Boundary 

 Ketley 



It. iLiglitnioor. 



Woombrulge-)- 

 Rock 



\Vrokiii + 



1000? 



20 

 45 



36 



15—50 



2200? 



20 

 30—90 



30 

 16—30 

 IG— 100 

 0—60 

 0—10 



N. 35' E. 



N. 20' E. 



N. 23° E. 

 N. 23' E. 



N. 10' E. 



N. 53' W. 



1 

 1 



2? 



1 



N. 15' W. 



N. 58' W. 

 N. 53' W. 

 N. 33' E. 



N. 88° E. 

 N. 10' W. 

 N. 40° E. 



N. 88° E. 

 N. 72' W. 

 N. 67° W. 



N. 45' W. 

 N. 70° E. 

 N. 25° E. 



N. 63' E. 



N. 63' E. 



N. 2.5' to 45' E 



N. .35' E. 

 N. 50' W. 



5 



1 1 

 1 1 

 1 



2 



1 4 

 5 



7 



1 



I 



I 



i 



4 



3 



4 



S.E. by E. 



W.N.W. 



W.N.W. 

 W.N.W. 



N. by E. 



S.W. by S. 



S.E. by S. 

 S.E. 



N.W. by W 



W. by S. 

 S.W. by S. 

 S.W. by S. 



W.N.W. 



S. ■ 

 W. by S. 

 S.E. by E. 



S. 



s.s.w. 



N.E. bv N. 



S. 45° W. 

 N.N.W. 

 W.N.W. 



S.S.E. 



S.S.E. 



N.W. by W. 

 N.E. bv N. 



I, G. Urn. 



Trail, I. 3. 

 Trap, II. 3. 



/, III. .1. ■ 



I, IV. o. 



Trap, A, i>l. 

 /, K, X. 



g, Li. bru. 



4, V. 8. 

 *, VI. a. 

 i, VII. /;. 

 5, VIII. li. 



8, IX. li. 



b, X. li. 



10, XI. 13. 



o, XII. 0. 



k, XIII. 10. 

 fc, W. r. 



w, R. 37. 



o, XIV. 16. 

 /!•, XV. 16. 

 /.. XVI. 15. 

 0. XVil. b. 

 0, XVIII. /;. 



0, XIX. o. 

 k, XX. a. 



Brings the Silurian and igneous rocks of Lilleshall into contact 

 with the New Red Sandstone. 



Bounds the coal field to the eastward, bringing the measures 

 on a level with the New Red Sandstone. It has not been posi. 

 tively proved underground, except at Pitchcroft. It is deflected 

 in its course. 



Visible in the lime quarry at Lilleshall. 



appa. 



Increase.? as it approaches theLilleshall but vanishes just before 

 it reaches the Lightmoor fault. 



Bounds the coalmeasures to the N. W., abutting them against the 

 New Red Sandstone. It is joined at Donnington by the Ketley 

 fault, and the union of the two forms the Lilleshall fault. In places 

 basalt appears along this fault. 



One of the earliest known large faults in the coal field. It 

 is frequently perpendicular and the sides of it often gape. At its 

 junction with the Boundary, it splits into numerous fan-shaped 

 branches. It decreases rapidly as it trends southward. 



Its course through the Wenlock shale and limestone cannot be 

 j ascertained with the same exactitude as through the coal field. 

 Its length is no doubt much greater than that which is here given. 

 J It will 1)6 perceived, that it does not range in a perfectly straight 

 I line. This is one of the best known and most important fault^ in 

 the coal field. Its effects vary greatly owing to its frequent junc- 

 l. tion with other faults. 



Increases but subdivides as it approaches the Boundary fault. 

 It crosses 5, by which it is slightly deflected. 

 It presents the same phenomena as No. 6. 



Decreases as it proceeds from the Lightmoor fault, of which it 



tisabranch; the chief fracture of the Lightmoor fault bending a 

 few degrees eastward at the point of divergence, 

 r ■ At its intersection with 8, no alteration of level is produced ; the 

 I faults neutralising each other, but shortly resume their previous 

 '- condition. See fault 12. 

 Increases and subdivides towards A. 



Perpendicular, and from 20 to 30 yards broad. It ramifies to- 

 wards 10. 



Apparently a continuation of 9 ; but the continuity being par. 

 tially destroyed by 8, it is considered as a distinct fault : it tra- 

 verses 10 without either fault being affected. 



Increases towards the Rock fault. 

 I J This fault is very irregular ; on meeting 10 it is deflected seve. 

 ) ral degrees eastward, and it terminates abruptly against 3". 



The great dislocation ranging parallel to the igneous axis of the 

 Wrekin, is apparently deflected slightly more to the northward 

 by its junction with theSteerawayslineof dislocation. The diagonal 

 of the two passing through Kinley Wick, where we find a pro- 

 truded boss of basalt. 



Increases rapidly in vertical importance towards k. 

 Ditto ditto. 



Thins off quickly as it recedes from b. The dip on the side of 

 lowest level is more than double that on the rise. 



The phenomena are the same as in No. 17. 



Commencing between the villages of New Hadley and Ketley, 

 it bends at Ketley and again at Steeraways. At a mile from its rise 

 its efffects are 100 feet. Past Steeraways it again decreases slightly, 

 afterwards the strata which arc nearly level on the rise of this 

 fault, dip rapidly towards it, in the swamp. 

 Runs parallel to k. 



From the rise side of this fault, the strata dip uninterruptedly 

 to New Hadley. 



