250 THE QEOLOGi' OF UARBADOS. 



Mr. Jiikes-Browne had sent him many specimens of the coral-lime- 

 stone for examination, and on these he had written two short 

 appendices to the paper. 



The rocks present some marked variations in structure, and, so far 

 as one can judge from hand-specimens and thin sections, it would 

 ajDpear that the limestones described by Prof. Dana in his " Coral 

 and Coral Islands " as the outer and inner reef-rock and the beach- 

 sand rock are represented in the coral-limestones of Barbados. 



Specimens of white limestones from Jamaica were also sent for 

 comparison. Of these some seem to be oceanic deposits, but others 

 are without much doubt coral-limestones, although the general details 

 of structure are obscured by the crystallization of the whole. 



Mr. Easton said that he had obtained the specimens of coral-rock 

 and other rocks exhibited during works now being carried on under 

 his superintendence. These works consisted of tunnels driven in 

 to bring to the surface the water collected in more or less defined 

 channels after percolating through the coral-rock. At least five 

 levels exist in which the water is found generally flowing on the 

 top of the lower beds under the coral-rock, which forms in each 

 case an escarpment of about the same height These escarpments 

 all bear evidence of having once been sea-coasts, and having been 

 successively raised to their present level. He had great pleasure 

 in submitting the specimens exhibited, and hoped to obtain more. 



Dr. Blaistfoed doubted whether the evidence produced was 

 sufficient to justify the assignment of the coral-reef beds to the 

 Pleistocene, for the proportion of recent species and the amount of 

 denudation described were compatible with greater antiquity. The 

 relations of the land-fauna in North and South America — for 

 instance, the distribution of the Cervidce — did not support the view 

 that the two continents were distinct throughout the later Ter- 

 tiaries, and were not united until the latter part of the Pleistocene. 

 It should be remembered that the removal of the Isthmus of Panama 

 could not have greatly influenced the phenomena of the Glacial 

 epoch ; the North Atlantic would have been rather colder, but this 

 would not explain the glaciation of other parts of the world, such 

 as British Columbia. 



The Peesideis^t remarked that the details supplied in the paper 

 formed an important addition to the literature of the coral-reef 

 question, showing as they did clear evidence of the elevation of old 

 coral-reefs. He thought the speculations appended by the Authors 

 as to the changes in the level of the South-American continent and 

 Central America somewhat out of place, and hardly warranted by 

 any of the observations recorded in the paper. No trifling sub- 

 mergence of the Isthmus of Panama would serve to divert the great 

 Equatorial current into the Pacific Ocean. Unless the downward 

 movement had been more serious than the Authors seemed to 

 suppose, the bulk of the current Avould still sweep round into the 

 Gulf of Mexico, only the upper waters passing into the Western 

 Ocean. 



