ZONE OF ARIETITES TURNERI. 47 



Spiriferina pinguis, Ziet. 

 — Walcotii, Sow. 



Rhynchonella variabilis, d'Orb. 

 Terebratula perforata, Piet. 



Brachiopoda. 



Terebratula cor., Lamk. 



— punctata, Sow. 



— indentata, von Buck. 



ECHINODERMATA, PoLYZOA, AWTHOZOA. 



Pentacrinus tuberculatus, Mill. Cidaris, sp. 



Neuropora mamillata, de From. Montlivaltia Sinemuriensis, de From. 



Foraminifera, 15 species. 



4. The Zone of Arietites Turneri. 



Synonyms. — " Hauptpentacrinitenbank des untern Lias," Quenstedt, ' Flozgeb.' 

 p. 152, 1843. " Lumachelle de Pentacrinites basaltiformis," Marcou, 'Jura salinois/ 

 p. 47, 1846. " Die Schichten des Pentacrinus tuberculatus " Oppel, ' Juraformation,' p. 44, 

 1856. " Tuberculatus-bed," Wright, 'Quart. Journ. Geol. Soc.,' vol xiv, p. 25, 1858. 

 " Marne de Strassen," Dewalque et Chapuis, ' Fossiles de Luxembourg,' 1853. " Zone of 

 Ammonites Turneri" Wright, ' Quart. Journ. Geol. Soc.,' vol. xvi, p. 403, 1860. 



This subdivision of the Lower Lias forms a well-marked zone of life. The beds 

 consist of light-coloured argillaceous limestone, of hard greyish limestone, or of deep-blue 

 shelly, indurated shale, interstratified with beds of dark-coloured clay. Many of the 

 slabs of limestone are covered with shells and portions of the stem and side arms of 

 Pentacrinus tuberculatus, Mill. From one of these slabs, collected at Frethern or 

 Purton, in Gloucestershire, Miller's original specimen of this Crinoid was obtained. 



Gloucestershire and Warwickshire. — The Turneri zone was exposed at Bredon, in the 

 deep cuttings of the Bristol and Birmingham Railway, from whence my type specimen 

 (PI. XII) was obtained. In the Vale of Gloucester portions of these beds are sometimes 

 laid open in making drains, as at Badgeworth and Hardwick ; and many fine slabs are 

 occasionally procured from the Severn section at Purton. I know of no locality in 

 Gloucestershire, where the entire series is shown. My late friend, Dr. Oppel, 1 referred the 

 Saurian beds of Brockeridge Common to this zone. This I have shown, at p. 17, to be 

 an error, as the Brockeridge Common-beds form a portion of the zone of Aegoceras 

 planorbis, whereas the Fish and Saurian beds at Lyme Regis, with which he identified 

 the Brockeridge-beds, certainly belong to the zone of Arietites Turneri, as the following 

 section indicates. In Warwickshire the Turneri beds constitute the base of what is 

 called in that county the " Cardinia-series ;" in these are included all the strata of the 

 Lower Lias between the Turneri and raricostatum beds, characterised by different 

 forms of the genus Cardinia. 



1 'Die Juraformation,' p. 49, 1856. 



