2 72 Mr. S. V . Wood on the Events which produced and terminated 



to the South Staffordshire coal-field, and precisely agrees, in that 

 part which would be between Folkestone and Maidstone, with 

 the chalk escarpment of the Weald Valley between those places. 

 The symmetrical form of the Weald Valley is interrupted at 

 Maidstone — the axis of the elevation, which proceeds due east 

 and west from the borders of Hampshire through Surrey and 

 West Kent, being deflected at this point to the E.S.E., a direc- 

 tion that it maintains until the tumescence is lost inland of 

 Boulogne. Now in the production of this palaeozoic axis, which, 

 bending northwards in the centre of the Pas de Calais, assumes 

 in stretching to the Straits of Dover at Cape Grisnez the direction 

 of E.S.E., we have presented to us a very apparent cause for the 

 sudden deflection of the Weald anticlinal from its normal direc- 

 tion. The presence of a " massif " of highly indurated palaeozoic 

 rock, with its planes of stratification arranged at angles uncon- 

 formable to the beds of mesozoic age abutting up to it, could 

 not, I conceive, fail to affect the upthrow of the beds subjected 

 to the elevatory action, producing the anticlinal by a tendency to 

 divert the line of upthrow into the direction of that of the ancient 

 " massif." The action to which I refer has, I imagine, operated in 

 all countries in interfering with the lines of strike, the symme- 

 trical direction of these lines being at points diverted or inter- 

 fered with without any apparent cause*. By a reference to the 

 chart annexed to the paper of MM. Degoussee and Laurentf, it 

 will be found that the line of the carboniferous trough there in- 

 dicated intersects, if produced under the chalk of Kent, the line 

 of the anticlinal of the Weald Valley about Cranbrook in Kent. 

 Now Cranbrook is the point at v/hich the Weald anticlinal 

 abruptly changes its direction of E. 5° N., W. 5° S.; to that of 

 E. 25° S., W. 25° N., which is that of the carboniferous axis 

 disclosed by the coal-borings of the two French departments. 

 The point where the Isle of Wight anticlinal would intersect the 

 carboniferous axis is east of Boulogne; but the point of inter- 

 section of a line drawn parallel to the palaeozoic axis, and at a 

 distance from it equal to the distance between the axes of the 

 Weald and the Isle of Wight, would fall out at sea east of 

 Beachy Head. The valleys of fracture in which the French 

 rivers from the Seine to the Somme run, are productions of 



* It would be irrelevant here to enlarge upon this subject, but there is 

 much that might be adduced to show that the irregularity in direction of 

 mountain-chains is proportional to the presence in them of "massifs" of 

 older rocks which have been thrown into anticlinals of an origin anterior to 

 the principal one of the system, and hence that the regularity of mountain- 

 chains is (in Europe at least, which has undergone so great disturbance in 

 every age) proportional also to the age of the system ; the more ancient the 

 system, the more regular its direction, if free from later disturbances. 

 t Quart. Journ. Geol. Soc. vol. xii. p. 252. 



