4 



BRITISH FOSSIL CORALS 



be studied. If this be done the association of the characteristic species of certain British 

 beds with the characteristic species of a lower geological horizon on the Continent becomes 

 evident, and the unphilosophical nomenclature of geologists who restrict themselves to 

 the study of small areas is exposed. 



In classifying the groups of species about to be described, in the geological scale 

 attention will be directed to the Ammonite-Zone in which they are found and to the 

 Mollusca associated with them. 



There are a few Triassic species in the Liassic Coral-fauna, and the Branching Corals of 

 the Sutton Stone have, generally speaking, a very Triassic facies. The majority of the 

 Corals of the lowest members of the Lias are peculiarized by the imperfection of their 

 septal arrangement: the distinct development of definite cycles in six systems is rarely 

 observed, and it would appear that this high organization was not attained in the forms 

 which had varied from Paleozoic into Mesozoic species. The Montlivaltia, Thecosmilia, 

 and Astroccenia of the Lower Lias of Glamorganshire illustrate this remark ; and the first 

 definite septal arrangement is met with in the Montlivaltia Haimei, Ch. et Dew, in the 

 Zone of Ammonites angulatus at Marton. 



The septal number is also very uncertain in the species of the above-mentioned genera 

 in the Lower Lias, and multiseptate Montlivaltia are found in the same deposit as those 

 possessing an unusually small number of septal laminas. It may, in fact, be asserted that 

 the so-called rugose peculiarities had hardly left their hold upon Madreporarian life at 

 the time when the lowest members of the Lias were deposited. The genus Elysastraa, 

 Laube, retains some " rugose " peculiarities, and the transition from the tabulae and 

 vesicular endotheca of a Cyathojjhyllum to the dissepiments and vesicular endotheca of 

 some forms of Montlivaltia polymorpha, Terq. et Piette, is certainly within the bounds of 

 possibility. Nevertheless, no Palaeozoic genera of Corals have been found in the Lias 

 except as "remanie" fossils. 



The genera which are represented in those subdivisions of the Lias called the Zones 

 of Ammonites planorb is and Ammonites angulatus are — 



I. Montlivaltia. 

 II. Rhabdophyllia. 



III. Thecosmilia. 



IV. Oppelosmilia, gen. nov. 

 V. Isastraa. 



VI. Astroccenia. 



VII. Cyathocosnia, gen. nov. 

 VIII. Elysastrcea. 



IX. Septastraa. 

 X. Latimceandra. 



