Geological Society of London. 379 



The author first referred to the synonyms and geological distribu- 

 tion of Caryophyllia cylindracea, Eeuss, which, has hitherto been 

 regarded as peculiar to the White Chalk, and as necessarily an ex- 

 tinct form, inasmuch as it belonged to a group possessing only four 

 cycles of septa in six systems, one of tbe systems being generally 

 incomplete. The distribution of the Caryophyllice of this group in 

 the Gault and the Upper Chalk, the Miocene, and the Pliocene, was 

 noticed, and also that of the species with tbe incomplete cycle. The 

 falsity of this generalization was shown to be proved by the results 

 of deep-sea dredging off the Havannah, under Count Pourtales, and 

 off the Iberian peninsula under Dr. Carpenter and Mr. Gwyn Jeffreys. 

 The former dredged up Caryophyllia formosa with four complete 

 cycles, and the latter obtained, from depths between 690 and 1090 

 fathoms, a group of forms with four complete and incomplete 

 cycles. This group had a Cretaceous facies; one of the forms 

 could not be differentiated from Caryophyllia cylindracea, Eeuss ; 

 and as a species of the genus Bathycyathits was found at the same 

 time, this facies was rendered more striking. The representation of 

 the extinct genera Trochosmilia, Parasmilia, Synhelia, and Dihlasus, 

 by the recent Amphihelice, Faracyathi, and Caryophyllice was 

 noticed, and it was considered that as the Cretaceous forms throve 

 under the same external conditions, some of them only being per- 

 sistent, there must be some law which determines the life-duration 

 of species like that which restricts the years of the individual. It 

 was shown that deep-sea conditions must bave prevailed within the 

 limits of the diffusion of the ova of coral polyps somewbere on the 

 Atlantic area ever since the Cretaceous period. 



Discussion. — Mr. Gwyn Jeffreys remembered that at the spot where the coral in 

 question was dredged up the sea-bottom was extremely uneven, varying as much as 

 fifty fathoms within a quarter of a mile. It was also not more than forty miles from 

 land. The species of mollusca dredged up were extremely remarkable, and many 

 were totally different from what he had previously seen. They were, however, 

 living or recent ; none of them were Eocene or Miocene, much less Cretaceous, Kke 

 Terebratula caput-serpeniis. He quoted from Mr. Davidson other instances of the 

 persistence of forms, especially of the genus Lingula from the Silurian formation. 

 The persistence of this species of coral, as well as that of Foraminifera, from the 

 Cretaceous to the present time, was therefore not unique, and other cases of survival 

 from even earlier times might eventually be recognized. 



Dr. Carpenter, after commenting on the reductions that extended knowledge 

 enabled naturalists to make in the number of presumed species, could not accept the 

 mere identification of species as of the highest importance in connecting the Cretaceous 

 fauna with that of our own day. The identity of genera was, in his opinion, of far 

 more importance. He instanced Echinothuria, and Rhizocrinus, as preserving types 

 identically the same as those of a remote period, and as illustrating the continuity of 

 the deep-sea fauna from Cretaceous times. The chemical and organic constitution of 

 the deep-sea bottom of the present day was also singularly analogous to that of the 

 Chalk sea. The low temperature at the bottom of the deep sea, even in equatorial 

 regions, was now becoming universally recognized, and this temperature must have 

 had an important bearing on the animal life at the sea-bottom. 



Prof. Eamsay thought that there was some misapprehension abroad as to the views 

 held by geologists as to continuity of conditions. They had, however, always in- 

 sisted on there having been an average amount of sea and land during all time ; and 

 the fact of sea having occupied what is now the middle of the Atlantic since Creta- 

 ceous time would create no surprise among them. If, however, the bed of the 

 Atlantic were raised, though probably many Cretaceous genera, and even species, 



