GEOLOGY 19 
ments into an ellipsoidal dome or pericline. This dome was traversed 
along a north-east to south-west axis by a major fault, which displaced 
the relative levels of the two halves so that the denuded south-eastern 
portion only raises its jagged crags above the mantle of Keuper Marls, 
while much of the remaining portion still lies buried to the north-west. 
Faults and thrusts, however, have greatly dislocated large blocks of 
rocks, thus disturbing the general continuity of the beds around this 
semi-ellipse or periclinal dome. Many of the subdivisions, however, 
can be located so as to reconstruct the once perfect continuity of the 
pericline. 
The movements which produced these structural features directed the 
intrusion of igneous rocks. 
Into the pyroclastic volcanic rocks, grits and slates of the Forest several 
types of igneous rocks were intruded, the chief of which are quartz- 
diorite-porphyries, or so-called ‘ porphyroids,’ and augite-syenites. 
The quartz-diorite-porphyries, or so-called ‘ porphyroids,’ which 
occur at Peldar Tor, High Sharpley, High Cademan, Grimley, High Tor 
Farm, Birch Hill and elsewhere were first intruded. These bear strong 
evidence of shearing and crushing, probably by the main north-west and 
south-east movements of pre-Cambrian date. These rocks only occur 
in the north-west portion. Lenticular-shaped masses and bosses of 
augite-syenite, granophyric in texture, which bear no marked evidence 
of shearing, and which, therefore, were of later intrusion than the 
* porphyroids,’ occur in Bradgate Park, at Groby, Markfield, Hammercliffe, 
Bawdon Castle, Newhurst and elsewhere in the Forest. Further afield, 
at Enderby, Narborough and Croft, Earl Shilton and Stoney Stanton, 
finer-grained igneous rocks occur, giving rise to noticeable tumulus-like 
hills. ‘These latter, however, may possibly be of later age. 
The main folding, faulting and cleaving of the Charnwood Forest 
deposits, and the intrusion into them of the igneous rocks, appear to 
have taken place in pre-Cambrian times. But from that date onwards 
until Middle Triassic times, if not somewhat later, the region was sub- 
jected to denudation. At the present time the majority of the rocks 
are only just being uncovered, and so, as Prof. Watts has picturesquely 
stated, ‘ they still present a scarcely altered Triassic landscape ; to this 
day many of the summits are as rugged and precipitous as when they 
were mountain tops overlooking a Triassic desert, or just submerged 
beneath the waters of a Triassic lake.’ 
In the Nuneaton district, lying to the south of Atherstone, Cambrian 
rocks—Stockingford Shales—traversed by numerous dykes of diorite 
occur. The igneous rock lies in sheets and varies greatly in thickness 
from 200 ft. to small veins, often following the line of strike. The 
Warwickshire coalfield succeeds the Cambrian shales on a synclinal 
trough to the south. 
The only intrusion of granitic rocks exposed in the area and for a 
considerable distance beyond its boundaries is the Granite of Mountsorrel. 
Covered by a mantle of Keuper Marls, its extent beneath the cover is 
unknown. 
Investigations of the extent of the Mountsorrel area eastwards have 
