644 C. CALLAWAY ON THE PRECAMBRIAN 
from my determination of the (at least) Upper Cambrian age of the 
quartzites which flank the Wrekin axis. 
It is proposed in the present paper to describe the lithological 
and stratigraphical character of these rocks, and to state in full the 
evidence for their Precambrian age. In a subsequent communica- 
tion an attempt will be made to trace the physical history of this 
Precambrian mountain-chain, to describe the association of the 
bedded rocks with subsequent eruptive greenstones, and to correlate 
the Precambrian groups of Shropshire with other known forma- 
tions. The recent recognition by the author of the Lilleshall Pre- 
cambrian rocks on the eastern flank of the Malvern Hills*, and of 
the Malvern schistose types at the base of the Wrekin series, has an 
important bearing on the last inquiry ; but details are, for the pre- - 
sent, reserved. 
I have to acknowledge my great obligation to Prof. Bonney, 
F.R.S., for his invaluable and willing aid in working out some diffi- 
cult points in lithology. Mr. Allport’s paper on the Wrekin, 
already referred to, has also been of great assistance. 
A. PuysicaL GEOGRAPHY OF THE WREKIN AND Carr Carapoc CHAIN. 
In Shropshire, this chain of hills is twenty-nine miles in length 
from N.E. to S.W.; but, if we include in it the elevations west of 
Kington, in Herefordshire and Radnorshire, which are probably in 
part composed of rocks of the same series, the line will reach nearly 
fifty miles. These hills do not form an unbroken range, but are 
here and there separated by broad intervals of comparatively level 
ground. ‘The more typical forms are triangular in transverse sec- 
tion, and semilunar viewed from the N.W. or 8.E., the greater 
length lying in the general direction of the chain. They are easily 
distinguished from the round-backed elevations of the Longmynd 
on the N.W., and from the ridges of the Caradoc Sandstone on the 
S.E., by their abrupt slopes and conical forms. They constitute a 
median axis, on each side of which run several parallel ridges with 
their escarpments facing towards it. On the west is the Longmynd 
range, succeeded at a distance of six miles by the abrupt edge of 
the Stiper Stones. On the east appear in succession the parallel 
elevations of Hoar Edge, the Chatwall ridge, and, at a greater dis- 
tance, the sharp escarpment of Wenlock Edge, overtopped by the 
less angular and less regular ridge of the Aymestry Limestone. 
Most of the flanking ranges lie in comparatively unbroken straight 
lines, and fall down steeply on the side looking towards the Precam- 
brian axis ; while the axial rocks themselves present a cone or boss 
at intervals only, and slope abruptly and evenly to both south-east 
and north-west. 
The following are the principal elevations, commencing at the 
north-east end of the chain :— 
* Messrs. Hill and Bonney, Quart. Journ. Geol. Soc. vol. xxxiy. p. 287, 
aote §, also recognize a second Precambrian group at Malvern, 
