part 4] THE MIOCEXE OF CEYLOX. 



2L. The Miocene of Ceylok. By Edward James Waylaid. 

 M.I.M.M., F.G.S., and Arthur Morley Dayies, D.Sc, 

 F.GLS. (Read May 10th, 1922.) 



[Plates XXVIII & XXIX— Fossils.] 



Part I. — Stratigraphy. (By E. J. W.) 



It has long been known that fossiliferous limestones occur in 

 the Jaffna peninsula in the extreme north of Ceylon, but until 

 recently they have received little attention, and nothing approach- 

 ing a detailed account of them appears to have been published. 



At various times between 1911 and 1916 (inclusive) in the 

 capacity of Assistant Mineral Surveyor for Ceylon, I carried out 

 geological investigations over a stretch of more than 800 miles of 

 the coast-line of the island. During the progress of this work 

 sedimentary beds were frequently met with; and the best-developed 

 group of these — the Miocene — is dealt with in this paper. It will 

 be shown that the Jaffna limestones are of Miocene age, that 

 similar limestones occur elsewhere in Ceylon, and that Miocene 

 rocks of other facies also occur. 



I am at a disadvantage in that all my field-notes, being the 

 property of the Mineral Survey, remain in Ceylon ; but sufficient 

 information is contained in private note-books to allow of a general 

 description. 



Prior to Dr. Davies's determination of the contained fossils the 

 age of the Jaffna limestones was very uncertain ; for, while I 

 recognized them as Tertiary, and regarded them as probably 

 Eocene, a previous author believed them to be of Cretaceous age. 1 

 Sir Emerson Tennant regarded them as a recent coral-formation, 2 

 and this view is still held by engineers and others who have 

 occasion to deal with them ; while Mr. J. S. Boake, in a very 

 ingenious, if entirely imaginary, representation of Cejdon geology, 3 

 depicted them as covering lateritic deposits which can be demon- 

 strated not to antedate the human period. 4 



The two facies of the Miocene are («) calcareous, typically 

 shown in the Jaffna peninsula, and (6) areno-argillaceous, typically 

 shown at Minihagalkanda, Southern Province. The limestones 

 attain considerable thickness, and are highly fossiliferous. The 

 areno-argillaceous beds are usually less than 50 feet thick, and 

 unf ossilif erous : only at Minihagalkanda do they include thin inter- 

 calations of limestone with an abundant fauna. 



1 A. C. Dixon, ' The Koeks & Minerals of Ceylon ' Journ. Ceylon Branch, 

 ttoy. Asiat. Soe. vol. vi, pt, 2 (1880) p. 39 [22]. 



2 ' Ceylon ' 1860, pp. 12-20. 



•' ' Mannar : a Monograph ' Colombo, 1888. 



' E. J. Wayland, ' Outlines of the titone-Ag'es of Ceylon ' Spolia Zeylanica, 

 vol. xi, pt. 11, Oct. 1919. * 



