1871.J DUNCAN PEHSISTENCE Oi' CARYOPHYLLIA crLINDEACEA. '439 



was also not more than forty miles from land. The species of Mol- 

 lusca also procured in this dredging were extremely remarkable, and 

 many were quite new to him. They were, however, living or recent 

 species ; none of them were Eocene or Mioceue, much less Cretaceous, 

 like Terebratala caput-serpentis. He quoted from Mr. Davidson 

 instances of the persistence of Brachiopoda, especially of the genus 

 Lingula from the Silurian formation: The continuance of this species 

 of coral, as well as of certain Foraminifera, from the Cretaceous to 

 the present time was therefore not exceptional ; 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, ia his opinion, of far 

 more importance. He instanced Echinotliuria 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 univer- 

 sally recognized ; and this temperature must have had an important 

 bearing on the animal life at the sea-bottom. 



Prof. Ramsay thought that there was some misapprehension 

 abroad as to the views held by geologists as to continuity of condi- 

 tions. They had, however, always insisted 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, might be found, there would on the whole 

 be a very marked difference between these Atlantic beds and those 

 of the Chalk. 



Mr. Seelev had already, in 1862, put forward views which had 

 now been fully borne out by recent investigation. His conviction 

 was that, from the genera having persisted for so long a time, the 

 genera found in any formation afforded no safe guide as to its age, 

 unless there were evidence of their having since those formations 

 become extinct. 



Mr. Exheridge maintained that the species in different formcttions 

 were sufficiently distinct, though the genera might be the same. 

 Recent dredgings had not brought to light any of the characteristic 

 moUuscan forms of the Cretaceous time ; and it would be of great 

 importance to compare the results of future operations with the old 

 Cretaceous deep-sea fauna. 



Prof. Rttpert Jones, with reference to the supposed sudden ex- 

 tinction of chambered Cephalopods, remarked that Cretaceous forms 

 had already been discovered in Tertiary beds in North America, and 

 also that cold currents could not have destroyed them, seeing that 

 icebergs came down to the latitude of Croydon in the Chalk sea. 



