part 4] ON THE MIOCENE OF CEYLON. 585 



In studying the marine fossils I have had the advantage of com- 

 paring them directly with Sowerby's and A. d'Archiac & Haime's 

 types, now preserved at the British Museum (Natural History). 

 I owe many thanks to Dr. A. Smith Woodward for facilities given 

 for this work, to Mr. li. B. Newton for criticism and advice during 

 its progress, and to Mr. G. C. Itobsou for help in examining recent 

 Indo-Paeific shells. I visited Paris with the object of studying 

 other Miocene collections, and it is with great pleasure that I recall 

 the very courteous and helpful way in which I was received by 

 French palaeontologists; in particular MM. G. F. Dollfus, H. Dou- 

 ville, M. Cossmann, and M. Cottreau, who devoted much time to 

 searching through collections and to the discussion of points 

 of interest. To Mr. G. S. Sweeting I am much indebted for 

 assistance in the photography of specimens. 



A complete series of the fossils, including all type- and figured 

 specimens, has been presented by Mr. Wayland to the British 

 Museum (Natural History). 



The collections of fossils described and figured by J. de C. Sowerby 

 from Kach, and by A. d'Archiac & J. Haime from Sind, were in 

 both cases stratigraphically mixed. Subsequent sorting has not 

 been facilitated by the fact that in each case, by a strange fatality, 

 most of the specimens are recorded as from a ' ghost ' locality — 

 • Soomrow ' in Kach (identified by Wynne as possibly Trummo) 

 and the ' chaine d'Hala ' in Sind, which appears to exist solely in 

 school geography-books. The only published attempt at a reference 

 of the fossils to their several horizons is that by Fedden (1879 l ), 

 although much unpublished information is probably in the possession 

 of the palaeontologists of the Indian Geological Survey. In the 

 following tables (pp. 58(3-87) the columns that indicate previous 

 records of the species with which the Ceylon, fossils seem most 

 closely comparable are based principally upon Fedden's tables. 



When we compare the lists from the two most prolific localities, 

 Kirimalai and Minihagalkanda, we see that they have few species 

 in common. Yet, if we take all those identifiable with Sowerby's 

 or A. d'Archiac's types, and classify them according to the probable 

 stratigraphical position as given by Fedden, we get very little 

 guidance as to age, either absolute or relative. In both cases we 

 find species of Gaj and pre-Gaj age with others that are most com- 

 parable with recent forms. Any deduction as to age, based on their 

 relative proportions, is unsafe for several reasons : — (1) few of the 

 identifications are exact, and, in the case of a fauna which evolved 

 so slowly as that of the Indian Ocean (Vredenburg, 1911), approxi- 

 mate identifications do not form a safe basis for the percentage 

 method; (2) it was generally easier to compare these fossils with 

 other fossils than with recent forms, hence the references to recent 

 species are probably fewer than they might have been if the Ceylon 

 fossils had been better preserved; (3) Fedden's allocation of species 

 to horizons was tentative only. 



1 Dates in parentheses refer to the list of papers at the end (pp. 600-601). 



2b2 



