TRANSACTIONS OF SECTION C. 539 
eet increase in energy a series of sharp folds is well displayed in the coast of 
outh Wales and in an island in the Bristol Channel, ranging for that part of the 
east and west disturbance which is known as the Mendip axis. Thisname has been 
applied to a series of short anticlines which are arranged en échelon 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 the 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 mé/ée 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, con- 
stantly 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 échelon 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 of 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 Palzeozoic rocks which lie hidden 
beneath the 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 take place will he going far towards locating any concealed coal- 
fields which may exist ; but the knowledge can be obtained only by boring, anc 
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 if 
they keep their course. Where exposed at the surface each post-Carboniferous 
syncline between two axes contains a coalfield. It remains to future exploration 
to ascertain whether similar conditions hold good under the Oolitic and Cretaceous 
areas of Central England. 
In speaking of the north and south disturbances I have in more than one case 
stated that the post-Carboniferous movement was but a renewal of activity along an 
old line of disturbance. The fact is proved by the unconformities visible among 
the pre-Carboniferous rocks, and it is important for the reason that the geography 
of this part of the globe at the commencement of the Carboniferous period had 
been determined by these movements. It has long been known, for example, that 
the parts of the counties of Stafford, Warwick, and Leicester traversed by the 
axes of upheaval were not submerged till late in the Carboniferous period. On 
the other hand, some of the area lying immediately west of the Malvernian axis 
was submerged at an earlier date, as is shown by the existence of Carboniferous 
Limestone at Cleobury Mortimer and, in greater development, in the Forest of 
Dean. The borings near Northampton also proved the presence of Carboniferous 
Limestone, a fact which is in favour of the occurrence of concealed coalfields, in so 
far as it indicates that the wMole Carboniferous series may have once existed there. 
