. Island life; or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. MAP OF THE SANDWICH 19LAND? The tint shows where the sea is less than 1,000 fathuins show the depth in fathoms. the North Pacific. We may be quite sure, therefore, that theSandwich Islands have, during their wdiole existence, been ascompletely severed from the great continents as they are now ;but on the west and south there is a possibility of more exten-sive islands having existed, serving as stepping-stones to t
. Island life; or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. MAP OF THE SANDWICH 19LAND? The tint shows where the sea is less than 1,000 fathuins show the depth in fathoms. the North Pacific. We may be quite sure, therefore, that theSandwich Islands have, during their wdiole existence, been ascompletely severed from the great continents as they are now ;but on the west and south there is a possibility of more exten-sive islands having existed, serving as stepping-stones to theisland groups of the Mid-Pacific. This is indicated by a fewwidely-scattered coral islets, ar(»und which extend considerable 300 ISLAND LIFE. [part II. areas of less depth, varying from two hundred to a thousandfathoms, and which may therefore indicate the sites of submergedishmds of considerable extent. When we consider that eastof New Zealand and New Caledonia, all the larger and loftierislands are of volcanic origin, with no trace of any ancient strati- [60 C. F70. MAP OF THE NORTH PACIFIC WITH ITS SUBMERGED BANKS. The light tint shows where the sea is less than 1,000 fathoms dark tint ,, ,, .. more than 1,000 fathoms deep. The figures show the depths in fathoms. fied rocks (except, perhaps, in the Marquesas, where, accordingto Jules Marcou, granite and gneiss are said to occur) it seemsprobable that the innumerable coral-reefs and atolls, which occurin groups on deeply submerged banks, mark the sites of bygonevolcanic islands, similar to those which now exist, but which, after CHAP. XV.] THE SANDWICH ISLANDS. 301 becoming extinct, have been lowered or destroyed by denudation,and finally, by subsidence of the earths crust, liave altogetherdisappeared excej^t where their sites are indicated by the upward-growing coral-reefs. If this view is correct we should give up allidea of there ever having been a Pacific continent, but shouldlook upon that vast ocean as havin
Size: 1612px × 1549px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwallacealfredrussel18, bookcentury1800, bookdecade1880
