132 
PRE-CARBONIFEROUS FLOOR OF THE MIDLANDS. 
strike-faults or folds, which, however, seems very probable, 
must be as much as 25,000 feet. We see neither the base nor 
the top of these beds, for they are bounded by great faults both 
on the east (near Church Stretton) and on the west. The 
western line of fault runs along the centre of the valley, 
which separates the Longmynd Hills from the ridge of the 
Stiper Stones. In this valley Dr. Callaway has recently 
detected numerous small bosses of Pre-Cambrian strata, of 
which Pontesford Hill occupies the largest area. Still walk¬ 
ing westward we find the ascent to the Stiper Stones to be 
composed of the Shineton Shales. The Stiper Stones them¬ 
selves are quartzose sandstones distinguishable lithologically, 
and by the fact that they contain an Arenig fauna, from the 
Wrekin quartzite. They may be regarded as forming the 
true base of the Silurian system, and are comparable with 
the Gres Armoricain of Brittany. They are overlaid by 
Arenig Shales, beyond which Upper Silurian rocks stretch 
westward into Wales. 
10. —The Malvern Hills .—About thirty miles south-east 
of Church Stretton we find the Malvern Hills. They rise in 
conical masses from the plain of the Severn, being bounded 
on their eastern side by a fault of great magnitude. Gneissic 
and granitoid rocks form the core of the range, and are well 
exposed at the Herefordshire Beacon, Worcester Beacon, and 
North Hill. These are overlaid by indurated volcanic rocks, 
ashes, and lialleflintas, certainly belonging to the Pebidian 
division of the Pre-Cambrian era. Dr. Callaway has 
identified both these varieties of rocks in the Wrekin 
district.* The rocks exposed below the Quartzite at the 
Lickey, and at Hartshill, in all probability belong to the 
Pebidian formation, together with the entire series of the 
Cliarnwood rocks. 
On the west side of the Malverns we find the Hollybush 
Sandstone resting upon the Pre-Cambrians (the Quartzite 
being absent), while above it are the Malvern Shales (com¬ 
parable in part with those at Shineton and Stockingford). 
All the Lower Silurian strata are missing, but the Upper 
Silurians are in full force, the May Hill Sandstone forming 
their base, and they extend northwards to Abberley, and west¬ 
wards until they disappear beneath the Old Bed Sandstone. 
11. —Borings which have reached the Pre-Carboniferous 
Bocks in the Midlands. —“ Soundings on land,” in search of 
either coal or water, have been executed at numerous points 
within the Midland Counties during the last few years. 
* Quarterly Journal Geological Society, Yol. XXXVI., p. 536. 
