438 PKOCEBDIJirGS OF THE GEOLOGICAL SOCIETY. [June 7, 



follows that deep-sea conditions must have prevailed within the limits 

 of the diffusion of the ova of coral polypes somewhere or other on the 

 Atlantic area ever since the Cretaceous period. The deposits which 

 were formed during the Eocene period in clear deep oceanic water 

 far off from coral-rerfs and muddy rivers have not been discovered ; 

 consequently the oceanic corals of the period are still unknown. 

 The muddy sea-deposits and the vast aggregations of reef- corals and 

 Nummulites so almost invariably associated abound ; and in the Py- 

 renees and in the Hal a mountains of Sindh there are littoral and 

 shallow sea-corals found with Nummulites. These last-mentioned 

 deposits and those of the London clay and Paris basin present evi- 

 dences of the existence of neighbouring deep seas as yet unnoticed 

 geologically. 



I have already advanced, in former communications, proofs that 

 the reefs of the Miocene age of Europe were continued across the 

 Atlantic, through the Caribbean Sea, and into the great ocean-desert 

 of the eastern Pacific when the Isthmus of Panama and vast tracts 

 of land to the north and south of it were sea-floors. According to 

 the theory which distinguishes between the deep-sea and reef-build- 

 ing corals, the descendants of the Cretaceous oceanic forms could not 

 be found on the remains of that belt of islands which are to be traced 

 in the West Indies, the Ealuns and away to the east far past Vienna, 

 and along the Italian peninsula. In fact, they have not been dis- 

 covered in those deposits. 



But with the first evidences of deposits far from reefs and well 

 adapted for the invertebrate life of the deep sea come the proofs of 

 the persistence of deep-sea coral forms. The older Pliocene of Sicily 

 (the Zanclean of Seguenza) yields GaryophyJUoe with four cycles, and 

 species with shapes like those of the former deep seas, although with 

 important structural distinctions. 



At the present time in the deepest known coralliferous depths of 

 the eastern Atlantic the persistent species, its varieties, and the 

 representatives of its former associates are living in consequence of 

 the resumption of the external conditions which favoured their ex- 

 istence before the initiation of the great alterations in the relative 

 level of the land and sea which destroyed the majority of the Cre- 

 taceous forms on the European areas before the age of Nummulites. 

 It is unnecessary to enlarge upon this part of the subject, as it has 

 been so ably handled by the President in his last Address ; and it 

 therefore remains for me to conclude this communication by remind- 

 ing the Society that I have attempted to show that deep-sea corals 

 may persist somewhere through the ages when littoral and reef- and 

 muddy deposits were formed in their proper area, and may return 

 upon the resumption of the former physical conditions. 



DlSCTTSSION. 



Mr. GAVY^^ Jeffeeys remembered that at the spot where the coral 

 in question was dredged up the sea-bottom was extremely uneven, 

 varying as much as 350 fathoms within a quarter of a mile. It 



