38 Reports and Proceedings. 



explained, with the relations of the two faunas to one another. The 

 author then referred to certain exceptional species, indicated the 

 genera, the species of which constitute the existing reefs, and con- 

 tributed to form those of the past, and noticed the representatives of 

 some modern genera in old reefs. He pointed out that a correspon- 

 denc3^ of physical conditions during the deposition of certain strata 

 was indicated by their containing analogous forms, — the presence of 

 compound coenenchymal species indicating neighbouring reefs, and 

 their absence in places where simple or non-coenenchymal Madre- 

 poraria are found being characteristic of deep-sea areas remote from 

 the Coral seas. By applying the principles thus elaborated to the 

 evidence as to the condition of the seas of the European area from 

 the Triassic period to the present time, the author showed what 

 must probably have been the physical condition of this part of the 

 world at different periods. 



Discussion. — Prof. Alexander Agassiz accounted for the circumscribed area of 

 many corals in the Atlantic, from the young of many coral species attaching themselves 

 within a few hours of their becoming pelagic. He traced to the great equatorial 

 current, which must have traversed the Isthmus of Panama and Sahara in a pre- 

 cretaceous period, the distribution of certain forms, which the rising of the Isthmus 

 of Panama eventually checked.. He thought that the limits of the depth at which 

 true reef-building corals existed would be considerably extended in consequence 

 of recent discoveries by means of dredging. He mentioned the formation of a reef 

 at the present time off the coast of Florida, which threw light on the manner ia 

 which mudflats were formed and the sea eventually filled. 



Mr. J. Gwyn Jeffreys objected to the term deep sea being applied to a depth of 

 10 fathoms only, when the tide in some places rose to that extent, and the laminarian 

 zone extended to 15. He suggested 50 fathoms as a more appropriate measure. He 

 remarked on the great vertical range of some simple species of corals, such as 

 CaryophylUa, amounting to at least 150 fathoms from low-water mark. In deep-sea 

 "water it frequently was attached to various shells, such as Ditnopa and Aporrhais. 

 The only other simple coral of our seas was never found at a depth of less than 75 

 fathoms. The compound corals occurred only at great depths. 



Dr. Duncan drew a distinction between coral-reef areas and those in which 

 different conditions prevailed. His argument had not so much been based on the 

 depth of the sea as on the presence or otherwise of coral-reefs. The term deep sea had 

 been given by Prof. Forbes to depths of 10 fathoms and upwards. For such depths 

 as those explored at the present day no term short of " abyssal" was appropriate. 



The President called the attention of the Fellows of the Society to 

 a proposed memorial to the late Baron Alexander von Humboldt, and 

 another to the late Prof. J. B. Jukes, in aid of which contributions 

 were desired, and recommended these memorials to the favourable 

 consideration of the Fellows. 



II. — December 8th, 1869. — The following communications were 

 read : — 1. " Notes on the Brachiopoda hitherto obtained from the 

 Pebble-bed at Badleigh Salterton, near Exmouth, in Devonshire." 

 By Thomas Davidson, Esq., F.E.S., F.G.S., &c. 



The author first described the general characters, and discussed 

 the opinions that have been put forward as to tlie origin, of the 

 pebbles forming this bed. Nearly 40 species of Brachiopoda have 

 been obtained from them. The fossils contained in the pebbles have 

 been regarded as of Lower Silurian age ; the author considered the 

 great majority of the Brachiopoda to be Devonian. The species 

 identified with Silurian fossils are: — Lingula Lesuetiri (Rouault), 



