Chapter 15

sea-shells at its base, situated six miles inland, which, according to the traditions of the natives, was once surrounded by the sea. Captain Low has also described (Ibid., part i., page 131) mounds of shells lying two miles inland on this line of coast.

[24] “Notices of the East Indian Arch.” Singapore, 1828, page 6, and Append., page 43.

[25] Captain B. Hall, “Voyage to Loo Choo,” Append., pages xxi. and xxv. Captain Beechey’s “Voyage,” page 496.

Dr. Davy[26] describes the northern province of _Ceylon_ as being very low, and consisting of a limestone with shells and corals of very recent origin; he adds, that it does not admit of a doubt that the sea has retired from this district even within the memory of man. There is also some reason for believing that the western shores of India, north of Ceylon, have been upraised within the recent period.[27] _Mauritius_ has certainly been upraised within the recent period, as I have stated in the chapter on fringing-reefs. The northern extremity of _Madagascar_ is described by Captain Owen[28] as formed of madreporitic rock, as likewise are the shores and outlying islands along an immense space of _Eastern Africa_, from a little north of the equator for nine hundred miles southward. Nothing can be more vague than the expression “madreporitic rock;” but at the same time it is, I think, scarcely possible to look at the chart of the linear islets, which rise to a greater height than can be accounted for by the growth of coral, in front of the coast, from the equator to 2° S., without feeling convinced that a line of fringing-reefs has been elevated at a period so recent, that no great changes have since taken place on the surface of this part of the globe. Some, also, of the higher islands of madreporitic rock on this coast, for instance Pemba, have very singular forms, which seem to show the combined effect of the growth of coral round submerged banks, and their subsequent upheaval. Dr. Allan informs me that he never observed any elevated organic remains on the _Seychelles_, which come under our fringed class.

[26] “Travels in Ceylon,” page 13. This madreporitic formation is mentioned by M. Cordier in his report to the Institute (May 4th, 1839), on the voyage of the “Chevrette”, as one of immense extent, and belonging to the latest tertiary period.

[27] Dr. Benza, in his “Journey through the N. Circars” (the “Madras Lit. and Scient. Journ.” volume v.) has described a formation with recent fresh-water and marine shells, occurring at the distance of three or four miles from the present shore. Dr. Benza, in conversation with me, attributed their position to a rise of the land. Dr. Malcolmson, however (and there cannot be a higher authority on the geology of India) informs me that he suspects that these beds may have been formed by the mere action of the waves and currents accumulating sediment. From analogy I should much incline to Dr. Benza’s opinion.

[28] Owen’s “Africa,” volume ii., page 37, for Madagascar; and for S. Africa, volume i., pages 412 and 426. Lieutenant Boteler’s narrative contains fuller particulars regarding the coral-rock, volume i., page 174, and volume ii., pages 41 and 54. See also Ruschenberger’s “Voyage round the World,” volume i., page 60.

The nature of the formations round the shores of the _Red Sea_, as described by several authors, shows that the whole of this large area has been elevated within a very recent tertiary epoch. A part of this space in the appended map, is coloured blue, indicating the presence of barrier-reefs: on which circumstance I shall presently make some remarks. Rüppell[29] states that the tertiary formation, of which he has examined the organic remains, forms a fringe along the shores with a uniform height of from thirty and forty feet from the mouth of the Gulf of Suez to about latitude 26°; but that south of 26°, the beds attain only the height of from twelve to fifteen feet. This, however, can hardly be quite accurate; although possibly there may be a decrease in the elevation of the shores in the middle parts of the Red Sea, for Dr. Malcolmson (as he informs me) collected from the cliffs of Camaran Island (latitude 15° 30′ S.) shells and corals, apparently recent, at a height between thirty and forty feet; and Mr. Salt (“Travels in Abyssinia”) describes a similar formation a little southward on the opposite shore at Amphila. Moreover, near the mouth of the Gulf of Suez, although on the coast opposite to that on which Dr. Rüppell says that the modern beds attain a height of only thirty to forty feet, Mr. Burton[30] found a deposit replete with existing species of shells, at the height of 200 feet. In an admirable series of drawings by Captain Moresby, I could see how continuously the cliff-bounded low plains of this formation extended with a nearly equable height, both on the eastern and western shores. The southern coast of Arabia seems to have been subjected to the same elevatory movement, for Dr. Malcolmson found at Sahar low cliffs containing shells and corals, apparently of recent species.

[29] Rüppell, “Reise in Abyssinien,” Band i., s. 141.

[30] Lyell’s “Principles of Geology,” 5th edition, volume iv., page 25.

The _Persian Gulf_ abounds with coral-reefs; but as it is difficult to distinguish them from sand-banks in this shallow sea, I have coloured only some near the mouth; towards the head of the gulf Mr. Ainsworth[31] says that the land is worn into terraces, and that the beds contain organic remains of existing forms. The _West Indian Archipelago_ of “fringed” islands, alone remains to be mentioned; evidence of an elevation within a late tertiary epoch of nearly the whole of this great area, may be found in the works of almost all the naturalists who have visited it. I will give some of the principal references in a note.[32]

[31] Ainsworth’s “Assyria and Babylon,” page 217.

[32] On Florida and the north shores of the Gulf of Mexico, Rogers’ “Report to Brit. Assoc.” volume iii., page 14.—On the shores of Mexico, Humboldt, “Polit. Essay on New Spain,” volume i., page 62. (I have also some corroborative facts with respect to the shores of Mexico.)—Honduras and the Antilles, Lyell’s “Principles,” 5th edition,