Identifier: islandlifeorphen001wall (find matches)
Title: Island life : or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates
Year: 1911 (1910s)
Authors: Wallace, Alfred Russel, 1823-1913
Subjects: Biogeography Islands Glacial epoch
Publisher: London : Macmillan
Contributing Library: California Academy of Sciences
Digitizing Sponsor: California Academy of Sciences Library

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he sea ismore than 2,000 fathoms deep. It seems probable, then, that to the north-east ofMadagascar there was once a series of very large islands,separated from it by not very wide straits; while east-ward across the Indian Ocean we find the Chagos andMaldive coral atolls, perhaps marking the jjosition of otherlarge islands, which together would form a line ofcommunication, by comparatively easy stages of 400 or500 miles each between Madagascar and India. Thesesubmerged islands, as shown in our map at p. 425, are ofgreat importance in explaining some anomalous featuresin the zoology of this great island. If the rocks of Secondary age which form a belt aroundthe island are held to indicate that Madagascar was onceof less extent than it is now (though this by no meansnecessarily follows), we have also evidence that it hasrecently been considerably larger; for along the east coastthere is an extensive barrier coral-reef about 350 milesin length, and varying in distance from the land from
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CHAP. XIX THE MADAGASCAR GROUP 416 a quarter of a mile to three or four miles. This seemsto indicate recent subsidence ; while we have no recordof raised coral rocks inland which would certainly markany recent elevation, though fringing coral reefs surrounda considerable portion of the northern, eastern, and south-western coasts. We may therefore conclude that duringTertiary times the island was usually as large as, and oftenprobably much larger than, it is now. Biological Features of Madagascar.—Madagascar possessesan exceedingly rich and beautiful fauna and flora, rivallingin some groups most tropical countries of equal extent,and even when poor in species, of surpassing interestfrom the singularity, the isolation, or the beauty of itsforms of life. In order to exhibit the full peculiarityof its natural history and the nature of the problemsit offers to the biological student, we must give anoutline of its more important animal forms in systematicorder. Mammalia.—Madagascar poss

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