CHAP. VIII 
THE MALVERN HILLS 
133 
If, then, this volcanic group underlies the whole of the Longmynd 
series, and if, as it now appears, that series is older than the Olenellus-zonQ 
of the Lower Cambrian rocks, we can hardly include the volcanic rocks of 
the Wrekin and Caer Caradoc in the Cambrian system. They must belong 
to a still older geological formation, and I think we cannot do better than 
adopt for them Dr. Callaway’s name, Uriconian. 
There are still, however, many problems to he solved before the 
geological history of that region is completely understood. The rocks of the 
Longmynd must be more fully worked out. It is improbable that strata 
which look so likely to yield fossils should for ever prove barren. The 
lower half at least may be hopefully searched, although the upper massive 
reddish sandstones and conglomerates offer less prospect of success. On the 
west side of the Longmynd, above Pontesbury, there occiu’s a small area of 
volcanic rocks like those of the Wrekin district, including a well-marked 
nodular felsite and fine tuffs. These rocks have been regarded by Dr. 
Callaway as anotlier axis of the Uriconian series. It is very difficult, how- 
ever, by any combination of geological structures, to bring up a portion of 
the very bottom of the Longmynd series and place it apparently at the top. 
This is a feat which a detailed study of the region, and the detection of 
uuconformabilities in the Longmynd, may possibly accomplish. In the 
meantime, however, I would venture to suggest whether it is not more 
probable that we have here a detached area of much younger volcanic rocks, 
like those which, in various districts, may be included in the Cambrian 
system, and Avhich will be referred to in some detail in subsequent pages. 
V. THE MALVEUN VOLCANO 
Pegarding the age and origin of the oldest rocks of the Malvern Hills 
some controversy has arisen, and no general agreement has yet been reached.^ 
It is clear that the core of crystalline rocks which is overlain unconformably 
I’y the Hollybush Sandstone must be older than the Upper Cambrian rocks. 
There is no good evidence of any stratigraphical break in the Cambrian 
system of England or Wales, and it may be reasonably inferred that the 
break seen at the base of the Hollj^bush Sandstones indicates that the rocks 
underneath that horizon are pre-Cambrian. Some portions of these 
certainly very ancient rocks are gneisses or schists ; others have been 
described as “ felsites,” and have been regarded as passing into schists, and 
us the original material from which portions of the foliated series of the 
range have been produced by mechanical deformation. Not improbably the 
' There is no room here for a full bibliograjihy of the geological literature devoted to this 
locality. In the monograph by J. Phillips in vol. ii. part i. of the Memoirs of the Geological 
H^urvey, a list of writings is given up to the time of its publication in 1848. Since that year 
many additional papers have appeared. I may especially refer to H. B. Holl, Quart. Journ. 
Geol. Soe. xxi. (1865) p. 72 ; J. H. Timins, op. cit. xxii. (1867) ; Mr. F. Rutley, op. eit. .xliii. (1887) 
P- 481 ; Dr. Callaway, op. cit. xliii. (1887) p. 625, xlv. (1889) p. 47.5, .xlix. (1893) p. 398 ; Prof. 
Green, op. nU. li. (1895) p. 1 ; Mr. H. D. Aclaud, Geol. Mag. 1894, p. 48. 
