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Show 300 ISLAND LIFE. [PART If. areas of less depth, varying from two hundred to a thousand fathoms, and which may therefore indicate the sites of submerged islands of considerable extent. When we consider that east of New Zealand and New Caledonia, all the larger and loftier islands are of volcanic origin, with no trace of any ancient strati- MAP OF HIE NORTH PACIFIC WITU ITS SUBJ\ll~lWED BANI\S.. The light tint shows where the Ron. is less than 1,000 f'1tthnms cleep. ~'he rlnrk tint , .. .. mm\J than 1,000 fathoms deep. The figures show the depths in l'•tthoms. fied rocks (except, perhaps, in the Marquesus, where, according to Jules Marcou, granite and gneiss are said to occur) it seems probable that the innumerable coral-reefs and atolls, which occur in groups on deeply submerged banks, mark the sites of bygone volcanic islands, similar to those which now exist, but which, after CITAP. XV.j THE SANDWICH lSLANDS. 301 becoming extinct, have been lowered or destroyed by denudation, and finally, by subsidence of the earth's crust, have altogether disappeared except where their sites are indicated by the upwardgrowing coral-reefs. If this view is correct we should give up all idea of there ever having been a Pacific continent, but should look upon that vast ocean as having from the remotest geological epochs been the seat of volcanic forces, which from its profound depths have gradually built up tlte islands which now dot its surface, as well as many others which have sunk beneath its waves. The number of islands, as well as the total quantity of land-surface, may sometimes have boon greater than it is now, and may thus have facilitated tho transfer of organisms from one group to another, and more rarely oven from the American, Asiatic, or Australian continents. Keeping those various facts and considerations in view, we may now proceed to examine the fauna and flora of the Sandwich Islands, and discuss the special phenomena they present. Zoology of the Sandwich Islands: Birds.-It need hardly be said that indigenous mammalia are quite unknown in the Sandwich Islands, the most interesting of the higher animals being the birds, which are tolerably numerous and highly peculiar. l\fany aquatic and wading birds which range over the whole Pacific visit these islands, twenty-four species having been observed, but even of these five are peculiar-a coot, Fulica alai; a moorhen, Gallinula sandvichensis ; a rail with rudimentary wings, Penn,ula millei ). and two ducks, Anas Wyvilliana and Be1·nicla sandvichensis. The birds of prey are also great wanderers. Four have been found in the islands-the short-eared owl, Otus bTachyot~ts, which ranges over the greater part of the globe, but is here said to resemble the variety found in Chile and the Galapagos; the barn owl, Strix jlammea, of a variety common in the Pacific; a peculiar sparrow-hawk, Accipiter hawaii ; and Buteo solitarius, a buzzard of a peculiar species, and coloured so as to resemble a hawk of the American subfamily Polyborinre. It is to be noted that the genus Buteo abounds in America, but is not found in the Pa~ific; and this fact, combined with the remarkable colouration, renders it almost certain that this peculiar species is of America~ origin. |