18G7.] DUNCAN WEST-INDIAN COEALS. 31 



synchronous ; for the dip of the strata is constantly from the centre 

 of the space whoso circumference is indicated by the present An- 

 tilles ; and if this was so, there is a probability that the areas of 

 more or less contemporaneous subsidence were in the Eastern Pacific, 

 and between the West Indies and Madeira. 



The palaBontology of the raised reefs and coralliferous strata of 

 the Pacific Archipelago is in its infancy ; and the examination of the 

 Madreporarian remains will be of the greatest interest. It is hoped 

 that the descriptions of the fossil Corals of the "West Indies wiU 

 assist these investigations, and that, following Reuss in his studies 

 of the fossil Corals of Java, the affinity between the Miocene Coral- 

 reefs of the Pacific and West Indies may be firmly established. 



Postscript. — Since this communication was read, I have received 

 the Proceedings of the Essex Institute, United States, for Eebruary 

 21, 1866. Mr. K. S. Shaler read on that date a paper, " Notes on 

 the Modifications of Oceanic Currents in Successive Geological 

 Periods." He states, p. 302, ^^ No pala^ontological evidence, tending 

 to prove the former connexion of the Atlantic and Pacific Oceans in 

 intertropical regions, has yet been published, so far as is known to 

 the author." Whilst I regret that Mr. Carrick Moore's able palseon- 

 tological proofs were unknown to Mr. Shaler, and that those I 

 have published have not reached the Essex Institute, it is satisfac- 

 tory to find the author of the ' Notes ' writing thus about the up- 

 heaval of Central America :— ^'The emergence of this region could 

 not have accomplished the disruption of the equatorial current at 

 this point until the Tertiary period had been somewhat advanced.'* 

 This is a satisfactory conclusion, and is very creditable to the per- 

 spicuity of Mr. Shaler ; for, as he does not allude to the labours of 

 Forbes and Godwin-Austen and Maury in any part of his essay, we 

 may take for granted that he had not the benefit, as we have, of 

 their researches. 



Mr. A. E. Yerrill gives some very interesting notes " On the 

 Polyps and Corals of Panama, wdth descriptions of New Species," 

 Proc. Essex Institute, p. 323, April 18, 1866. He states :— " The 

 differences in the character of the Polyp-fauna of the Atlantic and 

 Pacific sides of Central America are very remarkable. At Aspin- 

 wall coral-reefs occur having essentially the same features as those 

 of Florida and the West Indies." " But at Panama none of these 

 forms occur, nor even any of the genera of the families to which 

 they belong, with the exception of PoritesJ^ " The MilJepora alci- 

 cornis, so abundant on the Atlantic side, even at Aspinwall, is not 

 represented at Panama ; but Podllopora, an almost exclusively Pacific 

 and Indian-Ocean genus, is the most nearly allied form found at 

 Panama." Mr. Yerrill proceeds to notice the existence of the genus 

 Astrangia as peculiarly characteristic of the Panama region. He 

 adds : — " These remarkable differences between the two fauna3 do 

 not favour the theory that has been entertained by some geologists, 

 that there has been a communication between the two oceans at 

 this point, and that the gulf-stream flowed across the isthmus into 



