ON THE BRITISH FOSSIL CORALS. 159 



The number of species of Madreporuria in the British Cretaceous forma- 

 tions is therefore fifty-eight. 



MM. Milne-Edwards and Jules Haime had described twenty-three species 

 before this Eeport was commenced ; of these I have ventured to suppress 

 Parasmilia Mantelli, Trochocyatlms Konic/i, and Trochocyathiis Warbiirtoni. 



The coral-fauna of the British area was by no means well developed or 

 rich in genera during the long period during which the Cretaceous sediments 

 were being deposited. The coral tracts of the early part of the period were 

 on the areas now occupied by the Alpine Neocomian strata, and those of the 

 middle portion of the period were where the Lower Chalk is developed at 

 Gosau, IJchaux, and Martigues. 



There are no traces of any coral-reefs or atolls in the British Cretaceous 

 area, and its corals were of a kind whose representatives for the most part 

 live a depth of from 30 to 600 fathoms. 



Corals from the Oolitic Strata. 



The following authors have contributed to our knowledge of the Oolitic 

 Corals : — Parkinson, ' Organic Remains,' 1808. W. Conybeareand W. Phil- 

 lips, ' Outlines of the Geol. of Eng. and "Wales,' 1822. Fleming, ' British 

 Animals,' 1828. E. Bennet, 'Cat. Org. llemains, Wilts,' 1837. Fitton, 

 " Strata below the Chalk," Geol. Trans. 2nd series, 1843. Morris, 'Cat. of 

 British Fossils,' 1843. MM. Milne-Edwards and Jules Haime, ' Mouog.' (Pal. 

 Soc.) 1851. M'Coy, Ann. Nat. Hist. 1848 (several essays). W. Smith, ' Strata 

 Identified,' 1816. J. PhiUips, ' Geol. of Yorkshire,' 1829. R. C. Taylor, 

 Mag. Nat. Hist. 1830. S. Woodward, ' Synopt. Table of Org. Rem.' 1830. 

 G. Young, ' Geol. Survey of York,' 1828. R. Plot, ' Nat. Hist. Oxfordshire,' 

 1676. J. Walcott, ' Descr. and Fig. of Petref. found near Bath,' 1779. T. 

 Wright, M.D., F.G.S., Cotteswold Club Trans. 1866. 



An analysis of the work of these authors, with the exception of that of Dr. 

 Wright, is found scattered over the pages of MM. Milne-Edwards and Jules 

 Haime's " Monograph of the Oolitic Corals," Pal. Soc. 1851. No new species 

 of fossil Corals have been described from the Oolitic rock since that date. 

 During the last year I have added to the species already known five from the 

 Great Oolite, and thirteen from the Inferior Oolite. A careful study of the 

 251 ThecosniiUce of the Inferior Oolite at Crickley has enabled me to distin- 

 guish five very remarkable varieties of Thecosmilia gregaria, M'Coy, sp., and 

 to satisfy myself that the relations of the Thecosmilioi of the Lias to the 

 genera Isastrcea, Latimceandra, and others were repeated in the Inferior 

 Oolite. There are specimens of Thecosmilia gregaria in Dr. Wright's collec- 

 tion which, had I not had a considerable series to examine from other 

 sources, might have been associated with Reuss's new genus Heterogyra, with 

 Symphyllia and Latirtiaiandra. The relation of these genera to MontJivcdtia 

 has been noticed (except Heterogyra) in the first Report (Brit. Assoc. Report, 

 Norwich, p. 106 et seq.), and there is a clear proof that the same jAenomena 

 of evolution may occur consecutively. That is to say, the St.-Cassianitfon/Zi- 

 valtice. and Thecosmilice varied and became permanent, compound, and serial 

 corals of such genera as Elysastrcea, Isastrcea, and Latimaiandra : then the 

 Liassic Thecosmilice did the same ; and now it is evident that a Montlivaltia 

 of the Inferior Oolite occasionally took on fissiparous growth, and superadded to 

 others a marginal gemmation and a serial growth, and evolved forms which 

 cannot be distinguished from those of the genera above mentioned and Si/m- 

 phyllia and Heterogyra. There was evidently an inherent power of variation 

 which declared itself in the same direction during the ages which witnessed 



