Ordnance Geological Survey of England. 519 
shire, and at Cornden and Shelve in Shropshire, where numerous 
lines of contemporaneous trap alternate with Llandeilo flags and 
Caradoc sandstone, and where the strata on the flanks of erup- 
tive rocks are the seats of lead and copper ores, the sandstones being 
often converted into quartz rocks (Caradoe, Stiper Stones, Wrekin, 
&c. &e.). Combining the evidence of these tracts with those laid 
open by the extensive transverse sections which I formerly made in 
Montgomeryshire, in the north-western parts of the Silurian region, 
where the masses have been shown to roll over in great undulations 
from S.E. to N.W., I am fully prepared to admit the existence of a 
similar configuration in North Pembroke, West Caermarthenshire 
and Cardiganshire, districts with which I was very imperfectly ac- 
quainted, and where the aspect of rocks is at first sight, it must be 
admitted, very forbidding to those who search after fossil evidences, 
The greater, however, the difficulty, the greater is the merit of those 
who have solved the problem, and have thus established in parts 
of South Wales the precise relations of what were previously con- 
sidered to be anomalous masses. The result of this Survey, up to 
the present moment, is, that in one small part only of North Pem- 
broke is there any development of rock older than the strata con- 
taining Lower Silurian fossils, and this occurs in the promontory of 
St. David’s, with which I am familiar: this rock, I ean confidently 
say, is mineralogically undistinguishable from the close-grained purple 
greywacke of the Longmynd and Haughmond Hill in Shropshire ; 
and in both these localities it has hitherto been found as void of 
fossils as in the similar rocks of the Lammermuir Hills in the South 
of Scotland. 
In the south-eastern parts of the Silurian region, to which the 
Ordnance Geological Survey has also extended its labours, the ac- 
curacy of the chief lines which had been laid down, whether in 
May Hill, Usk, Woolhope, and the Malvern Hills, has been con- 
firmed ; and, under the vigilant eye of Mr, Phillips, some new spe- 
cies have been added to the former lists, both in the Lower and in 
the Upper Silurian rocks. Among the latter the Pentamerus Knightii 
has been found in a new locality, in the southern prolongation of 
the axis of Woolhope, thus showing how persistently the place of 
the Aymestry limestone is maintained ; whilst a species of that re- 
markable shell, the Pleurorhynchus, has been detected in true Wen- 
lock limestone. 
In relation to the west flank of the Malvern Hills, Mr, Phillips 
has, by very close researches, come to an important conclusion. 
Certain specimens of a peculiar conglomerate or breecia having 
been found by his sister Miss Phillips, in which the Pentamerus 
levis and other Caradoc fossils are associated with fragments of 
syenite, a further search was instituted, and a small boss of this rock 
was laid bare on the very edge of the syenite and in a vertical posi- 
tion, like most of the beds of the same formation along the north- 
western prolongation of these hills. ‘The conclusion drawn by Mr. 
Phillips is, that a portion at least of the crystalline Malvern chain 
was in existence when the Caradoc sandstone was formed, an infer- 
