ON THE STRATIGRAPHY OP BRITISH LTASSIC CORALS. 179 



16. On the Stratigraphical Position of the Corals of the Lias of the 



Midland and Western Counties of England and of South 



Wales. By Eobert E. Tomes, Esq., F.G.S. (Read May 9, 



1877.) 



[Plate IX.] 



Introduction. — The following stratigraphical list of Lias corals must 

 not be regarded as by any means a complete one, even for the dis- 

 trict above mentioned, but rather as a record of such species as I 

 have either collected myself, or such as have been collected within 

 my knowledge, and of which I can therefore speak definitely. This 

 will perhaps afford a sufficient reason for the somewhat personal 

 mode of expression made use of throughout the paper. The nomen- 

 clature for horizons which I adopt may possibly be regarded as rather 

 antiquated. Eor instance, instead of speaking of the zones of Ammo- 

 nites angulatus and ^4. BucMandi, the words " Lima-beds " are often 

 used. This is done advisedly, and for the following reasons: — 

 Ammonites Buclclandi is a very rare species throughout the midland 

 counties, and it becomes therefore an uncertain guide. And although 

 Ammonites angulatus is abundant enough ; its vertical range is so 

 great that, unless assisted by other associate organisms, it becomes 

 practically useless in determining the stratigraphical position of a 

 coral. The greater number of Isastrazce and Septastrcece occur in a 

 rather restricted bed underlying the so-called Ziwia-beds ; and in this 

 Ammonites angidatus occurs abundantly. But it also appears up 

 through the whole of the Lima-seiies, though less abundantly, and 

 through the clays containing Ammonites semicostatus and A. Tur- 

 neri*, and upwards to the top of the zone in which A. plani- 

 costatus and Hippopodium ponderosum appear. Erom this zone I 

 have myself taken it at the north-west end of Welford Hill, four 

 miles west of Stratford-on-Avon. But wherever I have found 

 A. angulatus abundant, and associated with Cardinia ovalis, there I 

 have often been successful in my search for the species of Isastrcea 

 and Septastrcea ; and this has, in almost every instance, been imme- 

 diately under the beds which contain the large Lima (L. gigantea) 

 in the greatest abundance. Hence my reason for adding the testi- 

 mony of the Lima and Cardinia to that of the Ammonite. 



Many of the species in this list have been described and figured by 

 Dr. Duncan in the volumes of the Paheontographical Society, from 

 specimens taken from localities here mentioned ; and the more ample 

 stratigraphical information herein contained will therefore be a 

 useful addition to his valuable monograph. 



As might be anticipated, with greater attention paid to the corals 

 of the Lias, several new species have been met with, more especially 



* The great vertical range of Ammonites angulatus has also been noticed by 

 Mr. Moore, who found it high up on the Bridgend section, South Wales, asso- 

 ciated with A. semicostatus and A. Sauzeamis. See Quart. Journ. Geol. Soc. 

 vol. xiii. p. 511. 



