Recent Discoveries in the Geology of Shropshire.—I.
By Charles Callaway, M.A., B.SC. Lond., F.G.S.
Introduction.
This paper, furnished at the desire of the Editors of this Journal, gives a brief outline of » paper read by me before the Geological Society, in March, 1877, and published in Vol. XXXIII. of the Society's Journal. Its object is to announce the discovery of a now area of Tremadoc and Pre-tremadoc rocks, near the Wrekin, with a fauna mainly composed of new species. Papers will probably be communicated on the quartzites of Shropshire, and on a recently discovered Pre-cambrian volcanic series of great interest and importance, when the rocks have been more completely worked out. Sir R. I. Marchison has described the area under consideration, from the Wrekin on the north-east to the May Hill sandstone at Kenley on the south-west, as composed oi strata of Caradoc age, the Wrekin itself being an igneous outburst altering the Caradoc sandstone an its flanks into quartzite.
The Geological Survey has followed Murchison, but has include, wader the name of "quartzite," certain sandstones in which I have detected fossils in abundance.
In the Journal of the Geological Society (Vol. X., p. 62,) Messrs. Aveline and Salter describe this area as Caradac, and Salter gives a list of fossils from {so-called} Lower Caradoc shales at Harnage and Shineton, mixing up Cambrian forms, such as Olenus, from Shineton, with Cambro-Silurian genera, such as Trinucleus, from Harnage, the shales at Shineton and at Harnage evidently being considered identical.
Salter, in the "Geological Magazine” for 1867, refers to the shales at Shineton, which he there records as "the top of the Llandeilo Flags proper." The same writer seems, in after years, to have been struck with the incongruous association of Cambrian and Cambro-Silurian forming; for, in "A Catalogue of the Collection of Cambrian and Silurian fossils contained in the Geological Museum of the University of Cambridge," published in 1873, while describing what he supposes to be a Triathras from Shineton, he suggests, "it is possible that the locality may include some Tremadoc beds." With this exception, geologists have regarded the rocks of the area nuder consideration as of Caradoc age.
I shall endeavour to prove that the shales at Shineton are of Tremadoc age, and that a part of the so-called "quartzite” between the shales and the Wrekin represents the Hollybush Sandstone of Malvern. The true quartzites are probably Pre-cambrian; and the igneous chain of hills, from Lilleshall Hill through the Wrekin, the Lawley, Cacr Caradoc, and on to the south-west, are clearly stratified, and underlie unconformably the Cambrian racks,
Lower Caradoc Rocks.
Mr. Salter noticed at Harnage and on Cound Brook certain shales containing Trinucleus concentricus, Eaton, Beyrichia conmplicata, Salt,
