Vol. 51.] AND PHYSICAL GEOLOGY OF THE WEST INDIES. 297 



specific life that these changes indicate a considerable age for the 

 High-level Eeefs. Our faith, however, in that conclusion is dis- 

 turbed by two facts. In the first place, it appears probable that the 

 inclusion of the nine recent species in the Nivaje Shale is due to an 

 intermixture of specimens from different horizons in Heneken's 

 collection, before it was studied by Prof. Duncan. In the second 

 place, two of the extinct species and one of the genera new to the 

 "West Indian fauna occur, not in the High-level, but in the Low- 

 level Reefs, where they are associated with a moliuscan fauna of 

 late Pleistocene age. 



Until a considerable collection of the mollusca of the High-level 

 Eeefs is available for comparison, it will not be possible to decide 

 whether the whole of the raised limestones are Pleistocene, or 

 whether part should be included in the Pliocene. That the latter 

 will have to be done is most probable. The impossibility of sepa- 

 rating the Pleistocene and the Pliocene in Tropical America has 

 been shown by Prof. A. Heilprin x in the case of Yucatan, by Dr. A. 

 C. Lawson 2 on the Western Coasts, and by M. Purves 3 in Antigua. 

 The two systems probably merge also in Barbados. 



A maximum age for the High-level Eeefs is given by the fact 

 that they overlie the beds of the Oceanic Series. The age of these is, 

 however, still uncertain. Neither of the two fossils of any value as 

 time-tests, that occur in them, are known elsewhere. As was re- 

 marked at the time of their description, their evidence is insufficient 

 to enable us to do more than simply call them Upper Kainozoic* 



The Age of the Scotland Beds. — A lower limit to the age of the 

 Oceanic Series ' could be determined if we could settle that of the 

 ' Scotland Beds' upon which it rests. Deposits of similar character 

 to the latter occur in other of the Lesser Antilles and are there part 

 of a longer series than is exposed in Barbados. The palseontological 

 evidence, however, by which to correlate the Scotland Beds with 

 those of neighbouring islands is meagre in the extreme. It consists 

 of only three species of mollusca, which were described by Forbes, 3 

 and which were then peculiar to the island. These fossils gave 

 no very definite evidence until Guppy 6 discovered two of them in 

 Trinidad. He disputed the correctness of Porbes's views as to the 



1 A. Heilprin, ' Geological Researches in Yucatan,' Proc. Acad. Nat. Sci. 

 Phil. 1891, p. 141. 



2 A. 0. Lawson, ' The Post-Pliocene Diastrophism of the Coast of Southern 

 California,' Bull. Dep. Geol. Univ. Calif, vol. i. (1893) no. 4, p. 159. 



3 J. C. Purves, ' Esquisse stratigraphique et Especes fossiles de l'ile d'An- 

 tigoa,' Ann. Soc. Make. Belg. vol. viii. (1873) Bull. p. xxviii ; also ' Esquisse 

 geologique de l'ile d'Antigoa,' Bull. Mus. Hist. Nat. Belg. vol. iii. (1884) p. 312. 



4 J. W. Gregory, ' Cysteehinus crassus, a new Species from the Radiolarian 

 Marls of Barbados, and the evidence which it affords as to the age and 

 origin of those deposits,' Quart. Journ. Geol. Soc. vol. xlv. (1889) pp. 647, 648; 

 and ' Archeeopneustes abruptus, a new Genus and Species of Echinoid from the 

 Oceanic Series in Barbados,' ibid. vol. xlvii. (1892) p. 168. 



6 E. Forbes in Schomburgk's ' History of Barbados,' pp. 565-567. 



6 R. J. Lechmere Guppy, ' Remarks on the Cultivation of Scientific Know- 

 ledge in Trinidad,' Proc. Sci. Assoc. Trinidad, pt. ii. (1867) pp. 81, 82; 'The 

 Tertiary Microzoic Formations of Trinidad,' Quart. Journ. Geol. Soc. vol. xlviii. 

 (1892) p. 524. 



