GEOLOGY OF SHROPSHIRE. 205 



RECENT DISCOVERIES IN THE GEOLOGY OF 

 SHROPSHIEE,— I. 



BY CHAHLES CALLAWAY, M.A., D.SC. LOND,, F.G.S. 



Intkoduction. 



This paper, furnished at the desire of the Editors of this Journal, 

 gives a brief outline of a 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 new 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 Shropsliire, and on a recently discovered Pre-cam- 

 brian volcanic series of great interest and importance, when the rocks 

 have been more completely worked out. Sir E. I. Murchison 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 

 of strata of Caradoc age, the "Wrekin itself being an igneous outburst 

 altering the Caradoc sandstone on its flanks into quartzite. 



The Geological Survey has foUowed Murchison, but has included 

 under 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. 

 Avehne and Salter describe this area as Caradoc, and Salter gives a list 

 of fossils from (so-called) Lower Caradoc shales at Hamage and 

 Shineton, mixing up Cambrian forms, such as Olenits, from Shineton, 

 with Cambro- Silurian genera, such as Trinucleus, from Harnage, the 

 shales at Shineton and at Hamage evidently being considered identical. 



Salter, in the " Geological Magazine" for 1867, refers to the shales 

 at Shineton, which he there regards 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 

 forms; for, in "A Catalogue of the Collection of Cambrian and Silui-ian 

 fossils contained in the Geological Museum of the University of 

 Cambridge," published in 1873, while describing what he supposes to be 

 a TriarthruH from Shineton, he suggests, " it is possible that the locality 

 may include some Trevmdoc beds." W^ith this exception, geologists have 

 regarded the rocks of the area under consideration as of Caradoc age. 



I shaU 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 Wx-ekin represents the Holly bush Sandstone of Malvem. 

 The true quartzites are probably Pre-cambrian ; and the igneous 

 chain of hills, from Lilleshall Hill through the Wrekin, the Lawley, 

 Caer Caradoc, and on to the south-west, are clearly stratified, and 

 underhe unconformably the Cambrian rocks. 



Lower Cab^vdoc Eocks. 

 Mr. Salter noticed at Hamage and on Cound Brook certain shales 

 containing Trinucleus concentricus, Eaton, Beyrichia compUcata, Salt.' 



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