MAY HILL SERIES. 9 1 



comprise calcareous grey grits, false-bedded and ripple-marked, 

 with numerous clay-galls, and they rest unconformably on the 

 Bala beds. 



Fossils have been obtained at Walsall, Chirbury, Norbury, 

 Church Stretton, and at the Bogmine, near Shelve, in Shropshire. 

 In this county, according to Messrs. Salter and Aveline, the Upper 

 Llandovery beds comprise the following strata (See Fig. 9, 

 P-58):'- 



Purple shales (Tarannon Shales), 200 to 400 feet thick. 



Thin limestone bands, interstratified with ochreous sandstone and argillaceous 



shales (Pentamerus beds). 

 Conglomerates and sandstones, loo feet. 



The Upper Llandovery rocks are developed in the Lower 

 Lickey Hills in Worcestershire, and in Staffordshire. At the 

 Lickey, low heathy hills occur chiefly composed of quartz-rocks, 

 lithologically identical in character with those masses on the 

 flanks of the Caradoc and Wrekin ; the main portion of these 

 rocks is of Cambrian age, but they are overlaid by quartz-grits and 

 sandstone of Llandovery age. (See pp. 45 and 65.)'-^ The fossils 

 from the sandstones of the Bromsgrove Lickey include Pentamerus 

 oblongus, P. lais, Orihis calligramma, etc. The older Lickey 

 quartzite, as observed by Dr. Buckland, furnished a large pro- 

 portion of the pebbles in the New Red Sandstone and Drift ; ^ 

 these pebbles occur over a large area, so that this exposure alone 

 would not have furnished the material, and no doubt, as Mr. W. 

 J. Harrison has suggested, the beds formerly extended over a much 

 larger area, and, where not denuded, are concealed by overlying 

 strata.* 



Tarannon Shales. 



These beds comprise smooth pale-blue, purple, and greenish- 

 grey slates and shales 1000 to 1500 feet in thickness. 



They were first noticed by Sedgwick, under the name of ' paste 

 rock.' They were named by the Geological Survey from their de- 

 velopment by the river Tarannon near Llanidloes, in IMontgomery- 

 shire, where they were mapped by Mr. Aveline. These shales form 

 the lowest part of the Silurian rocks of North Wales, and from 

 beneath the Denbighshire grits they are exposed in a narrow and 

 nearly unbroken line from the mouth of the Conway to near 

 Builth in Radnorshire, where they are strikingly unconformable to 

 the various underlying members of the Cambrian strata. ° 



They extend southwards to near Llandovery, where their thick- 



' Q. J. X. 63 ; see also H. Hicks, P. Geol. Assoc, vii. 295. 

 - A. Aikin, T.G.S. i. 208; Murchison, Siluria, edit. 5. 

 3 T. G. S. V. 507. 



'' Proc. Birmingham Phil. Soc. iii. 157. See also J. B. Jvikes, South Stafford- 

 shire Coal-field, edit. 2, p. in. 



* Ramsay, Geol. N. Wales, edit. 2, pp. 4, 14, 18, 2S1. 



