A. Strahan's Address to Section C, Geology. 459 



well displaj'ed in the coast of South Wales and in an island in the 

 Bristol Channel, ranging for that part of the east and west disturb- 

 ance which is known as the Mendip axis. This name has been 

 applied to a series of short anticlines which are arranged en echelon 

 along a line ranging east-south-east, but each of which runs east and 

 west. Among them we may distinguish the Blackdown anticline, 

 the Priddy anticline, the Penhill anticline, north of Wells, and th& 

 Downhead anticline, north of Shepton Mallet. With one exception 

 they all die out eastwards after a course of two to ten miles, but the 

 Downhead anticline holds its course into the Malvernian disturbance, 

 the two engaging in a prodigious melee south of Radstock. From 

 that much shattered region the Downhead anticline emerges, but the 

 Malvernian axis is seen no more, and, so far as can be judged under 

 the blanket of Secondary rocks, comes to an end. 



Mention has been made of the fact that many of the subsidiary 

 east and west folds die away on approaching the Malvernian axis. In 

 a general way we may attribute their disappearance to the influence 

 of the north and south movement, for it is commonly to be observed 

 in these great belts of disturbance that they are composed of 

 a number of parallel anticlines or elongated domes of upheaval, 

 constantly replacing one another ; it is a common feature also that 

 these subsidiary folds replace one another not exactly in the direction 

 in which they point, but that they lie en echelon along a line slightly 

 oblique to it. The behaviour of the South Wales and Mendip folds 

 is in accordance with these observations, and may be taken to indicate 

 that the effects of the east and west disturbance reached further 

 north in South Wales than they did in Somerset, or, in other words, 

 that they failed to penetrate as far into the region where north and 

 south movements were in progress as in the region where there were 

 no movements in that direction. 



The fact that the east and west folds keep their course across 

 the north and south wherever the two actually meet comes out 

 prominently, and supports the inference that they dominate the 

 structure of the Palaeozoic rocks which lie hidden beneath tha 

 Secondary rocks of the south and south-east of England. Somewhere 

 under this blanket of later formations the east and west axis- 

 presumably intersects the other disturbances which traverse the 

 Midlands. To ascertain where and how the intersections takes- 

 place will be going far towards locating any concealed coalfields 

 which may exist ; but the knowledge can be obtained only by 

 boring, and the number of such explorations as yet made is wholly 

 insufficient. The majority have been made in search of water, 

 and have been stopped as soon as a supply was secured. Near 

 Northampton the older rocks were reached at a small depth on 

 what is believed to be the underground continuation of the Charnian 

 axis, and a boring at Bletchley traversed what is thought to have 

 been a great boulder of Charnian rock, suggesting that the axis 

 is not far off; but with these exceptions the counties of Oxford, 

 Buckingham, Bedford, Huntingdon, Cambridge, and Norfolk are 

 unknown ground. Yet under these counties the axes must run 



