The newer rocks, common also to the Nicobars and Sumatra, are in Ritchie's Archipelago chiefly and contain radiolarians and foraminifera.
Kloss, In the Andamans and Nicobars (1903); E.
Butler, "Birds of the Andamans and Nicobars" (Proc. Bombay Nat.
Two groups of islands in the Bay of Bengal, the Andamans and the Nicobars; one group in the Arabian Sea, the Laccadives; and the outlying station of Aden at the mouth of the Red Sea, with Perim, and protectorates over the island of Sokotra, along the southern coast of Arabia and in the Persian Gulf, are all politically included within the Indian empire; while on the coast of the peninsula itself, Portuguese and French settlements break at intervals the continuous line of British territory.
The marine surveys of these islands are still meagre and unsatisfactory, but the whole of the Nicobars and outlying islands were surveyed topographically by the Indian Survey Department in 1886-1887, when a number of maps on the scale of 2 in.