•"80 MTC. E. J. WATLAND AND DA. A. M. DAVTES [vol. lxxix. 



The Jaffna Miocene is but very slightly disturbed. Slight 

 buckling is indicated by a few gentle folds running in an east- 

 north-easter^ direction. Vertical movement, actual or relative, 

 has been more marked. 



(2) Minihagalkanda. — Minihagalkanda (' man-rock-hill ') is 

 so called from a stack separated from the- main rock-mass and 

 carved by denudation into a striking resemblance to a standing 

 figure. It lies about 5 miles east of the Yala river, and is com- 

 posed of altered gneiss, though it is for sedimentary strata that 

 the vicinity is most noteworthy. These crop out for a distance of 

 about 2 miles, starting 2 miles east of the Pilinawa outlet, 

 and occur in cliffs about 100 feet high. They stand well back 

 from the sea. being separated from it by sand-dunes. Landwards 

 the high ground extends for about a quarter of a mile, and then 

 descends steeply to the jungle-covered plains of recent alluvium 

 only a few feet above sea- level. (This peculiar ridge-like elevation 

 of soft rocks more or less parallel with the shore is seen again near 

 the mouths of the Kalu Oya and Pomparippu rivers, in the North- 

 western Province.) The deposits must have once had a greater 

 lateral extension, the more landward parts having been removed 

 by denudation, while the remainder was preserved by the protective 

 agency of blown sand at a time when the land stood lower in 

 relation to the sea. Evidence enough exists of such a former 

 relation, for the sedimentary deposits rest upon a sea-worn lioor of 

 ancient crystalline rocks in which can be traced ancient gullies 

 and small inlets, now high and dry and some considerable distance 

 from the water's edge ; some of them contain reconstructed 

 deposits derived from the sedimentary rocks that stand Avell back 

 from them. An ancient line of cliff can also be traced. 



The present description deals chiefly with the exposures to be 

 seen in the walls of a natural amphitheatre spanning 1200 yards 

 at Minihagalkanda, where the succession is best displayed. Near 

 the shore the basement-bed is an unfossiliferous ferruginous grit, 

 varying from 4 to 6 feet in thickness ; it tends to thin landwards, 

 and near the north-eastern part of the amphitheatre is separated 

 from the gneiss by a thin bed of pipe-clay. On the east-north- 

 east a scoriaceous-looking sandstone replaces the grit ; it is about 

 10 feet thick, and is separated from the gneiss by a bed of litho- 

 marge 6 to 10 feet thick. Eastwards of this the gneiss rises up, 

 and is covered immediately by red earth. 



Above the grit come about 25 feet of poorly-consolidated gritty 

 argillaceous beds ; their upper limit is a calcareous band which, 

 traced eastwards, becomes more marked while others appear 

 beneath it. At about 1000 yards from the south-western limit of 

 the exposures no less than five calcareous bands separated by 

 gritty argillaceous beds are to be seen : here they are sufficiently 

 pure to be called limestones, but possess a decidedly nodular 

 character. They are either compact and hard or cavernous, and in 

 that ease, sometimes but not always, softer. Under the microscope 



