PRE-CARBONIFEROUS FLOOR OF THE MIDLANDS. 
103 
Above the May Hill Sandstone of the Lickey are Silurian 
shales with irregular bands of limestone representing the 
Wool hope Limestone, while at the southern end of the ridge, 
near Barnt Green, an old quarry in a wood reveals the Wen- 
lock Limestone. At the northern end, where the anticlinal is 
complete, Silurian rocks occur on the east and on the west 
sides of Rubery Hill, and these are overlaid in turn by coal- 
measures. Above these come Permian and Triassic strata, 
which abound in fragments of the older rocks. 
8 .—The Wrekin and Church Stretton District. —The Pre- 
Carboniferous rocks of Shropshire have been so ably described 
by Dr. Callaway that it will be only necessary to briefly re¬ 
capitulate his conclusions. 
About twenty miles north-west of Dudley—at Lille shall, 
in Shropshire—we reach the termination of an axis which 
extends from this point to the south-west for thirty or forty 
miles, and along which Cambrian and Pre-Cambrian rocks 
have been brought up on the east side of a line of fault. The 
Pre-Cambrian rocks were mapped by the Survey as intrusive 
greenstones, while the Cambrians were regarded as Silurian 
strata altered by the heat, &c., proceeding from the said 
greenstones at the time of the intrusion! Mr. S. Allport was 
the first to prove that the so-called greenstones were really 
bedded volcanic rocks.* They occur as isolated bosses at 
Lillesliall, the Wrekin Range, Wrockwardine, and Charlton 
Hill. Then there is an interval of six miles (occupied by 
Cambrian and Silurian strata) when the Pre-Cambrians again 
form the rounded hills north and east of Church Stretton, 
known as the Lawley, Caer Caradoc, Cardington Range, &c. 
The beds of altered volcanic ash, lava, &c., have a general 
strike from east to west, or across the direction of the ridges 
which they form. 
Resting unconformably upon these volcanic rocks we find 
a quartzite, about 200 feet thick, identical in appearance with 
that of the Lickey and Hartsliill. 
Above the quartzite—where the section is most complete, 
as on the east side of the Wrekin—is the Hollybush Sandstone, 
greenish or brown in colour, and about 300 feet thick. Its 
fossils prove it to belong to the Upper Lingula Flags, so that it 
is of Upper Cambrian age. Above this sandstone, which is 
little altered, are the Sliineton shales—bluish shale, 1,500 feet 
thick—containing many new species of fossils, which Dr. 
Callaway places on the horizon of the Lower Tremadoc Beds, 
and which must be of pretty nearly the same age as the 
Stockingford Shales of Warwickshire. 
* Quarterly Journal Geological Society, Yol. XXXIII., p. 449. 
