TRANSACTIONS OF SECTION C. 855 



of the world. The immense amount of marine denudation which characterises 

 this stage is particularly ohvious in the anticlinals, which were the first to sutler, 

 as they came under the planing action of the sea. 



Attention may be drawn to a peculiarity which has no doubt been observed 

 by many persons who have studied a map of the Bristol and Somerset Coal-field. 

 It will be seen that the strike of the Coal-measures is widely different on either 

 side of a line which may be drawn through Mangotsfield to a point north of 

 Eristol. The beds north of this line have for the most part a meridional strike, 

 nearly parallel with the present Cotteswold escarpment; south of this line the 

 strike is mainly east and west, though much curved in the neighbourhood of 

 ]^adstock and the flanks of the Mendips. Of course, this is only part of an exten- 

 sive change in the direction of flexure, much of which is still bidden under 

 Mesozoic rocks. Mr. Ussher, in the paper previously quoted, tells us that_ the hne 

 of change of strike may be traced in the general mass of the Palseozoic rocks, 

 from near Brecon in South Wales to the neighbourhood of Frome. This means 

 that within the Bristol district two distinct systems of flexure must have impinged 

 on each other in post-Carboniferous times. Have we not here, then, another 

 instance of extraordinary change within the limits of our area ? This time it is 

 not a mere change in the nature of a deposit, like that of the Old Red Sandstone 

 into the Devonian, or of the Carboniferous Limestone into the Culm-rock, but a 

 change in the direction of the elevatory forces, which had made its mark on the 

 structure of our island even at that early date. 



At this point I ought to quit the Palaeozoics; but there is just one subject of 

 interest which claims a momentary attention— viz. the probability of finding work- 

 able coal east of the proved Somersetshire field. I avoid the question of coal 

 Gouth of the Mendips as being too speculative, on account of the chances of 

 deterioration of the coal-measures in that direction. But, in view of the forth- 

 coming meeting of the British Association at Dover, the question of finding coal 

 to the eastward of Bath becomes a specially interesting subject for discussion. It 

 is also a matter of some consequence whether the hidden basin or basins belong 

 to the meridional or to the east and west system of flexures. The latter is most 

 likely to be the case.^ The vale of Pewsey has been mentioned as a suitable 

 locality for boring along the line of the recognised axis. 



But prospectors should bear in mind the warning of PLamsay, that the basins 

 containing coal are but few in comparison with the number of basins throughout 

 the Paleozoic rocks. No doubt the line indicated is more favourably situated for 

 coal-exploration than the Eastern Counties; where, for instance, the Coal Boring and 

 Development Company has lately gone into liquidation. The unsuitability of East 

 Anglia as a field for coal-prospecting was insisted on in my second anniversary 

 address to the Geological Society,- and the results seem to have been very much 

 what might have been expected. If coal is to be found beneath the Secondary 

 rocks the line of search should be carried through the counties of Kent, Surrey, 

 Berkshire, and Wiltshire, though the three latter counties have hitherto been 

 content to leave their underground riches unexplored. The Kent Coal Explora- 

 tion Company is doing some good work with a reasonable chance of success; 

 though if they wish to find coal sufficiently near the surface they had better 

 adhere as much as possible to the line of the North Downs, since operationson 

 the Sussex side are only too likely to be within the influence of the Kimmeridgian 

 gulf, which was proved to exist at Battle (Netherfield). Mr. Etheridge, I hope, 

 will have something to tell us as to the progress of the Kent Collieries Corporation, 

 who now carry on the work at Dover. 



Secondary or Mesozoic i^ocA-s.— Commencing a totally different subject, I must 

 now direct attention to the ' red beds,' and associated breccias so characteristic of 



1 The boring at Burford, where coal was found at a depth of 1,100 feet, below a 

 surface of Bathonian beds, at a point thirty-five miles E.N.E. of the extreme end of 

 the Bristol coal-field at Wickwar, is not included in this category; since it must 

 belong to the meridional system, and is altogether ovitside the prolongation of the 

 axis of Artois. 



- Quart. Jonrn. Geol. Soc. vol. 1. (lS9i), p. 70. 



