ZONE OF AEGOCERAS ANGULATUM. 27 



2. The Zone of Aegocebas Angulatum. 



Synonyms. — "Sandige Kalkeund Sandsteine mit Am. angulatus, Quenst.," ' Flotzgeb./ 

 p. 541, 1843. " Gres infraliasique " (pars), Dufrenoy et De Beaumont. 'Exp. Carte 

 Geol. France,' vol. ii, p. 157, 1848. "Gres liasique, gres de Hettange," Terquem, 

 'Paleont. du Dep. de la Moselle/ p. 11, 1855. "Die Schichten des Ammonites angu- 

 latus" Oppel, ' Juraformation,' p. 28, 1856. "Zone a Ammonites Moreanus,'' Martin, 

 " Pal. Stratigraph. de l'Infra-lias du Depart, de la Cote-d'Or," ' Mem. Soc. Geol. de 

 France,' p. 38, 2nd serie, 1860. " Augulatenschicten," Seebacli, " Der Hannoversche 

 Jura," p. 17, 1864. "Die Angulatenschichten die untere Jura," Brauns, p. 70, 1871. 

 "Zone d'A. angulatus," Dumortier, ' Etudes de Bassin de Rhone,' Prem. Pt., p. 100, 

 1864. " Zone of Ammonites angulatus^ Tate and Blake, ' Yorkshire Lias/ p. 46, 1876. 



The Angulatum-zone, so far as it has been exposed, appears to be imperfectly 

 developed in the Midland Counties, and from the difficulty experienced in separating its 

 beds from the BucMandi-sevies, they were grouped with the latter in my memoir. 1 On 

 the Continent, however, and especially in France, this zone forms a very important 

 horizon, and contains a rich fauna. M. Jules Martin/ in his valuable memoir on the 

 Infra-Lias of the department of the Cote-d'Or, says, " this zone forms one of the best 

 characterised palseontological horizons in the Cote-d'Or, and contains the richest and 

 most varied fauna. Limited to two or three yards in thickness, this deposit appears to 

 correspond to a period of animalisation of admirable fecundity. It is from these that 

 we have collected the charming fauna which we last year indicated, and which has such 

 intimate relations with the Hettangian fauna described by M. Terquem." From this 

 zone M. Martin has collected and catalogued — 1 Ichthyosaurus, 1 Ichthyodorulite, 10 sp. 

 of Cephalopoda, 63 sp. of Gasteropoda, 77 sp. of Conchifera, 5 sp. of Brachiopoda, 4 sp. 

 of Echinodermata, 10 sp. of Anthozoa, 3 sp. Annelida, and the debris of Crustacea. In 

 the Department of the Moselle M. Terquem 3 has enumerated 177 species from the same 

 zone. Aegoceras angulatum, (Schloth.), is found between Charmouth and Lyme Regis, in 

 dark shale, below the grey concretionary limestone, with a mammilated surface ; and 

 likewise in the same strata south-west of the Cob. From these beds I have collected 

 Aegoceras angulatum (Schloth.), Aeg. Moreanum (d'Orb.). 



This zone was well exposed in the Harbury cutting of the Great Western Railway, 

 near Warwick, although very few Mollusca besides Aegoceras angulatum were obtained 

 therefrom ; on the spoil-banks, even now, some good fragments are occasionally found. 

 On the coast of Yorkshire it occurs near Redcar, where it has been studied with much 

 care by Messrs. Tate and Blake, and they have given a detailed account of its beds in their 

 excellent work on the ' Yorkshire Lias,' p. 48, whence the following section is derived : — 



1 'Quart. Journ. Geol. S.,' xvi, p. 398, 1860. 



s 'Paleontologie stratigraphique d'lnfra-Lias du departement de la Cote-d'Or,' p. 39, 1860. 'Mem. 

 Soc. Geol. de France,' 2nd serie, torn, vii, Mem. No. 1. 



3 'Paleontologie du departement de la Moselle,' p. 12, 1855. 



