100 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



for a time, and some amount of elevation succeeded, we learn from 

 the denudation which aifected them, and from the unconformable 

 position of the overlying May Hill Sandstone without the interven- 

 tion of the Llandeilo, Caradoc, or lower Llandovery rocks. This 

 interval was the epoch of the outbursts of trap-rock which have 

 altered the Primordial strata on the eastern side of the Hereford- 

 shire Beacon ; for there are no remains of the May Hill Sandstone, 

 which there probably would have been had it been involved in the 

 outbursts. 



Whatever may have been the oscillations in level which occurred 

 during the latter part of the Lower Silurian period, we have evidence 

 that the metamorphic rocks were again above the sea-level at the 

 period of the deposition of the May Hill series, in the shallow- water 

 conditions of its lower beds, and in the pebbles and fragments of the 

 crystalline rocks which they contain*. There is, in fact, up to this 

 epoch nothing to show that they had ever been entirely submerged. 

 That the period of the May HiU rocks was, however, like that of 

 the Hollybush Sandstone and Black Shale, one of subsidence, is seen 

 in the overlapping of the beds which occurs in both series. 



The subsidence of the range, which recommenced in the May Hill 

 Sandstone period, appears to have been continued until after the lay- 

 ing down of the Lower Old Bed Sandstone, as all the succeeding mem- 

 bers of the Upper Silurian series follow each other in conformable 

 succession. Some purpHsh and greenish-coloured shales at the top 

 of the May Hill series may possibly be the representatives of the 

 Tarannon Shales ; and between these and the Woolhope Limestone, 

 which in the Malvern district consists chiefly of greenish shales with 

 a few impure calcareous bands, there is apparently a very gradual 

 passage ; and although a temporary oscillation may have occurred 

 here and there, the general tendency was to a regular depression 

 throughout. 



It is probable that the whole range became completely submerged 

 during this long epoch, judging from the relative height of the hills 

 to the thickness and present position of the Upper Silurian beds. At 

 the close of the Lower Old Bed Sandstone period, however, elevation 

 again took place, for not only is the middle division of the Devonian 

 system probably absent in this part of the kingdom t, but the Upper 

 Devonian beds, the Carboniferous Limestone, and the Millstone Grit 

 are all attenuated in the direction of the Malverns, and the Coal- 

 measures of Newent on the south, and of Martley, Bewdley, and 

 South Staffordshire on the north, are laid down unconformably on 

 the denuded surfaces of the Lower Old Bed Sandstone and Upper 

 Silurian rocks. 



It does not follow that this rise was continuous. On the contrary, 

 there were doubtless some oscillations, but from the period of the 

 Lower Old Bed Sandstone the general tendency was upwards ; and 



* The late Miss Phillips first observed this. (See also Phillips, op. cit. p. 125.) 

 In the Grullet Wood Pass the conglomerate contains fragments of the altered 

 rocks which form the eastern buttresses of the Herefordshire Beacon. 



t At least, there is no evidence of its presence. 



