The tertiary rocks which form such remarkable features in the geology of other countries are almost unknown in Ceylon; and the “clay-slate, Silurian, old red sandstone, carboniferous, new red sandstone, oolitic, and cretaceous systems” have not as yet been recognised in any part of the island.[1] Crystalline limestone in some places overlies the gneiss, and is worked for oeconomical purposes in the mountain districts where it occurs.[2]

[Footnote 1:  Dr. Gardner.]

[Footnote 2:  In the maritime provinces lime for building is obtained by burning the coral and madrepore, which for this purpose is industriously collected by the fishermen during the intervals when the wind is off shore.]

Along the western coast, from Point-de-Galle to Chilaw, breccia is found near the shores, from the agglutination of corallines and shells mixed with sand, and the disintegrated particles of gneiss.  These beds present an appearance very closely resembling a similar rock, in which human remains have been found imbedded, at the north-east of Guadaloupe, now in the British Museum.[1] Incorporated with them there are minute fragments of sapphires, rubies, and tourmaline, showing that the sand of which the breccia is composed has been washed down by the rivers from the mountain zone.

[Footnote 1:  Dr. Gardner.]

NORTHERN PROVINCES.—­Coral Formation.—­But the principal scene of the most recent formations is the extreme north of the island, with the adjoining peninsula of Jaffna.  Here the coral rocks abound far above high-water mark, and extend across the island where the land has been gradually upraised, from the eastern to the western shore.  The fortifications of Jaffna were built by the Dutch, from blocks of breccia quarried far from the sea, and still exhibit, in their worn surface, the outline of the shells and corallines of which they mainly consist.  The roads, in the absence of more solid substances, are metalled with the same material; as the only other rock which occurs is a loose description of conglomerate, similar to that at Adam’s Bridge and Manaar.

The phenomenon of the gradual upheaval of these strata is sufficiently attested by the position in which they appear, and their altitude above high-water mark; but, in close contiguity with them, an equally striking evidence presents itself in the fact that, at various points of the western coast, between the island of Manaar and Karativoe, the natives, in addition to fishing for chank shells[1] in the sea, dig them up in large quantities from beneath the soil on the adjacent shores, in which they are deeply imbedded[2], the land having since been upraised.

[Footnote 1:  Turbinella rapa, formerly known as Voluta gravis used by the people of India to be sawn into bangles and anklets.]

[Footnote 2:  In 1845 an antique iron anchor was found under the soil at the northwestern point of Jaffna, of such size and weight as to show that it must have belonged to a ship of much greater tonnage than any which the depth of water would permit to navigate the channel at the present day.]