270 PHYSIOGNOMY OF PLANTS. 



this eastern peninsula are situated the chains of Cochin China, 

 Siam, and Malacca which are parallel with each other, as well as 

 those of Ava and Arracan which all, after courses of unequal 

 length, terminate in the Gulfs or Bays of Siam, Martaban, and 

 Bengal. The Bay of Bengal appears like an arrested attempt of 

 nature to form an inland sea. A deep invasion of the ocean, 

 between the simple western system of the Ghauts, and the eastern 

 very complex trans-Gangetic system of mountains, has swallowed 

 up a large portion of the low lands on the eastern side, but met 

 with an obstacle more difficult to overcome in the existence of the 

 extensive high plateau of Mysore. 



Such an invasion of the ocean has occasioned two almost pyra- 

 midal peninsulas of very different dimensions, and differently pro- 

 portioned in breadth and length; and the continuations of two 

 mountain systems (both running in the direction of the meridian, 

 i, e. the mountain system of Malacca, on the east, and the Ghauts 

 of Malabar on the west) show themselves in submarine chains of 

 mountains or symmetrical series of islands, on the one side in the 

 Andaman and Nicobar Islands which are very poor in corals, and on 

 the other side in the three long-extended groups or series of Atolls 

 of the Laccadives, Maldives, and the Chagos. The latter series, 

 called by navigators the, Chagos-bank, forms a lagoon encircled by a 

 narrow and already much broken, and in great measure submerged, 

 coral reef. The longer and shorter diameters of this lagoon, or its 

 length and breadth, are respectively 90 and 70 geographical miles. 

 Whilst the enclosed lagoon is only from seventeen to forty fathoms 

 deep, the depth of water at a small distance from the outer margin 

 of the coral (which appears to be gradually sinking) is such, that 

 at half a mile no bottom was found in sounding with a line of 190 

 fathoms, and, at a somewhat greater distance, none with 210 

 fathoms. (Darwin, Structure of Coral Reefs, p. 39, 111, and 183.) 

 At the coral lagoon called Keeling- Atoll, Captain Fitz-Roy, at a 

 distance of only two thousand yards from the reef, found no sound- 

 ings with 1200 fathoms, 



"The corals which, in the Red Sea, form thick wall-like masses, 

 are species of M^andrina, Astraea, Favia, Madrepora (Porites), Po- 

 cillopora (hemprichii), Millepora, and Heteropora. The latter are 



