72 
PRE-CARBONIFEROUS FLOOR OF THE MIDLANDS. 
exposed, and there are numerous other exposures along the 
general line of outcrop, all of which have the same character. 
Where the diorite crosses the sedimentary rocks the latter 
are much altered, being baked, bleached, and shattered. 
Fossils of certain genera are fairly numerous, although 
imperfect; but the species are few. They include the trilobite 
Aijnostus (probably A. pisifonnis), and a small Limptlella which 
is very like L. ferriujinea . Professor Lapworth has also 
identified Lingulella Nicholsoni, Obolella Saltcri, Kuton/ina 
cingulata, and Acrotreta socialis. These are undoubtedly 
Cambrian species, but they are hardly sufficient to enable us 
to refer the Stockingford shales to a precise horizon in the 
Cambrian formation. Taking all points into consideration, 
however, we may, perhaps, assign these slialy beds to the 
period of the Upper Lingula Flags and Tremadoc Slates, 
in which the same general assemblage of fossils occurs. 
The Stockingford shales are separated from the coal- 
measures by a considerable fault which runs curving along 
the strike. It is marked by a line of brick pits, in which 
the rubbed-up material or “fault-stuff” is worked, and its 
effects are well seen in the deep pit in coal-measure binds 
and sandstones about a quarter-mile east of Stockingford 
station. All the diorite dykes end abruptly along this 
line of fault, showing that the period of their intrusion into 
the Cambrian shales was Pre-Carboniferous. 
4.— The Cambrian Hocks of DosthUl. —The western boundary 
of the Warwickshire coal-field is, like the eastern, marked bv 
the appearance of Cambrian rocks which have been brought 
to the level of beds of much more recent geological age, by 
the agency of faults running parallel to the strike of the 
strata. 
Dostliill is a low eminence, four miles south of Tamworth, 
and not far from the Kingsbury Station of the Birmingham 
and Derby Pailway. It owes its present elevation to igneous 
rocks of two or three varieties—mainly diorite—which traverse 
Cambrian shales. On the west of the hill, which rises pre¬ 
cipitously from the course of the River Tame, a line of fault 
runs, by which the Triassic strata are placed on a level with 
the Cambrian shales, while on the eastern side a parallel fault 
of less “throw” places the coal-measures in a similar position; 
the latter rocks are well exposed along the railway, and a line 
of collieries marks the outcrop of the coal-seams, which in 
some cases are worked from their outcrop almost vertically, 
so greatly have they been bent up by the elevating action to 
which the central slice of Cambrian strata — sandwiched 
between Carboniferous and Trias—owes its position. 
