Owing to its shape and conformation, there are no rivers and but few streams on Great Andaman, and during the dry season—January to April—there is some scarcity of water. Several creeks, however, are of sufficient depth to allow passage of boats for some distance into the interior. In the South Andaman the greater part of the drainage runs into the creeks, which ultimately leads off to the eastern shore, and in the North and Middle Andaman the bulk of the drainage seems to flow through gaps in the eastern range.
Little Andaman is swampy in many parts, and possesses a few small creeks.
On the western side, in which direction Great Andaman slopes gradually, banks of coral occur at distances of 20 and 25 miles from land. There are three of these, varying in length from 9 to 25 miles, all composed of dead coral and sand, with here and there single bunches of live coral 1 or 2 feet high. The water, which is so clear that on a calm day 8 or 9 fathoms looks like 20 feet, varies in its least depths from 3¾ to 6 fathoms, and, judged from the appearance of the bottom and the absence of reef-building coral, it seems probable that the surface débris of the banks is disturbed by the send of the sea, and that the rollers topple and break on the middle bank in the south-west monsoon, though they may not do so on the others.
This western coast is fully exposed to the south-west monsoon, and is by no means a desirable locality to be in at that season.
Dalrymple Bank, of the same nature, lies adjacent to Little Andaman, on the same side; but Invisible Bank, to the eastward, has depths of 17 to 50 fathoms, with a rock awash in the centre. This is of bluish-grey sandstone, so that the Bank, taking into account its irregular surface and the rapidly-increasing depths around, may be considered a submerged mountain-range, of the same formation as the oldest part of the Andamans—of which, Flat Rock, an isolated peak, rises alone above the sea. All these banks probably formed islands, or part of the Andamans, when the latter stood at a higher elevation than they do to-day.
Throughout the Archipelago the scenery is of exceeding beauty. The picturesquely undulating surface is clad everywhere, save where artificial clearings have been made, with the most luxuriant jungle, for, situated within the tropics, with a fertile soil, and a climate that for two-thirds of the year is somewhat moist, the islands are covered from hill-top to sea-beach with an unbroken mantle of dense vegetation, rendered almost impenetrable by cane-brakes and undergrowth of rattans and other creepers. All along the shores are either stretches of yellow sand or brilliant green mangroves, and the seas round the islands are of the clearest water imaginable.
The coast-line is everywhere deeply indented, and affords a number—most unusual for such a small group—of deep-water harbours and other anchorages, where complete shelter can be found for large ships in all weathers and seasons. The most known and the best—although Port Cornwallis is nearly as good, and has the advantage of being some twelve hours' steaming nearer to Calcutta and Rangoon—is Port Blair, where the Settlement has been placed; but on the same coast of Great Andaman are many others, the more important being, Macpherson's Straits, Shoal Bay, Port Meadows, Colebrooke Passage, and Stewart's Sound. On the west coast are situated, Port Andaman, Kwang-tung Harbour, Ports Campbell and Mouat, while in the Archipelago perfect anchorage is to be found either in Outram Harbour or in Charka-Juru,[85] Kwang-tung Strait, or Tadma-Juru.
These are well distributed all along the coasts, and were the Andamans situated in some position of greater political or commercial importance, they would form an invaluable possession for this reason. As it is, the islands are exploited merely as a convict establishment—an Indian Botany Bay—and the only industry of any magnitude appertaining to them is that of timber, for which indeed the harbours are very convenient, as the forests worked are all in the neighbourhood of the seashore, or are so placed that after the trees are felled the logs can be hauled by elephants to the many creeks, and floated down to where the vessels engaged in the business are anchored.
The geographical conditions, and more especially the Tertiary sandstone of which the large area of the islands consists, point to a former connection with Arakan, and, in accordance with these indications, it is found that the bulk of the flora is Burmese; but the forest trees are finer, being very lofty and straight, while not a few purely Malayan species find their northern limit in the Andamans. The flora is not related to that of Hindustan and India proper—a coincidence which can be partly explained by the insular climate and difference of soil.
The forests produce valuable woods, which can be used for many trade purposes—furniture; ship, boat and house building; railway carriages and sleepers; paving blocks, boxes, gun-carriages and stocks, pianos, etc.; and as profitable minor products, there are canes for furniture, rattans for walking-sticks, and gurjan oil. Some of the woods can be obtained in extremely large quantities; all possibly in sufficiency for any trade that may arise with the islands.