which raised the Malvern Hills. '^ ^^ 363 



have saved them from denudation. As_, however, the coal-fields 

 of Wyre Forest and the Clee Hills on the north present a less 

 development of the series than is seen in Dean Forest, I have 

 reduced the thickness of the Coal-measures and Carboniferous 

 limestone which once existed on the west of the Malvern Hills 

 to about 2300 feet. Adding these amounts to the thickness of 

 the Upper Silurian, Caradoc sandstone, and syenite, we obtain 

 a total of at least 13,000 or 14,000 feet for the amount of dislo- 

 cation between the two sides of the Great Fault j an amount 

 greater, perhaps, than can be paralleled in any other instance of 

 a single fault which the world can produce. Nearly one-half of 

 this amount may, however, be assigned to the more local forces 

 which elevated the Malvern syenite ; so that about 7000 or 8000 

 feet would represent the difference of level between the strata in 

 the less distm-bed parts of Herefordshire west of Malvern, and 

 their equivalents now buried beneath the New Red Sandstone of 

 Worcestershire, allowing about 1000 feet for the thickness of 

 the latter down to the subjacent Coal-measures. 



The fluid matter which I suppose to have thus forced up the 

 solid syenite may itself have never reached the surface. The 

 plutonic axis of Malvern seems only to exhibit its upheaving 

 effects, and shows no signs of fluid ejections contemporaneous 

 with the elevation. It is possible, however, that volcanic matter 

 may have poured out over the downcast area, where it is now 

 concealed by the New Red Sandstone. And the laterally in- 

 jected dyke of Brockhill, as well as the trappean masses in the 

 black shales on the west of Ragged Stone and Midsummer Hills, 

 are not improbably connected with the volcanic forces which 

 thrust up the syenite. This supposition appears to me at least 

 equally probable with that of Professor Phillips (Mem. Geol. 

 Surv., vol. ii. p. 56), that these greenstone eruptions were con- 

 temporaneous with, and overlaid the black Caradoc shales with 

 which they are in contact. In the arrangement of the strata 

 around Eastnor Park, we seem to have indications of a crater of 

 elevation, caused by an incipient volcanic eruption whose focus 

 never reached the surface. The great expansion and crumpled 

 condition of the Silurian rocks at Ledbury, and their general 

 semicircular arrangement round a central point, indicate a local 

 and special development of volcanic energy beneath. But the 

 syenitic axis itself affords no more signs of eruptive force at this 

 point than at any other. The efficient force seems to have acted 

 not in, but at the west side of this axis. A mass of basaltic 

 matter ejected beneath the Caradoc sandstone will explain these 

 phsenomena. Its ramifications would be likely to select the 

 black shales as being less resisting than the sandstones above 

 and below them, and would produce that series of trappean 



