. Island life; or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. er Azores and Bermuda offer great contrasts in physical features,but striking similarities in geographical position. The one isvolcanic, the other coralline; but both are surrounded by a wideexpanse of ocean of enormous depth, the one being about as farfrom Europe as the other is from America. Both are situatedin the temperate zone, and they differ less than six degrees inlatitude, yet the vegetation of the one is wholly temperate,w
. Island life; or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. er Azores and Bermuda offer great contrasts in physical features,but striking similarities in geographical position. The one isvolcanic, the other coralline; but both are surrounded by a wideexpanse of ocean of enormous depth, the one being about as farfrom Europe as the other is from America. Both are situatedin the temperate zone, and they differ less than six degrees inlatitude, yet the vegetation of the one is wholly temperate,while that of the other is almost tropical. The productions oftlie one are related to Europe, as those of the other are toAmerica, but they present instructive differences; and both HAP. XII.] OCEANIC ISLANDS. 239 afford evidence of the higliest value as to the means of dispersalof various groups of organisms across a wide expanse of ocean. THE AZORES, OR WESTERN ISLANDS. These islands form a widely scattered group, nine in number,situated between 37° and 39° 40 N. Lat. and stretching ina south-east and north-west direction over a distance of nearly. iUlLINK MAP OF THE Note.—The liglit tint shows where tlie sea is less than fathoms dark tint .. ., ,, more than 1,000 fathoms deep. The figures show depths in fathoms. 400 miles. The largest of the islands, San Miguel, is about fortymiles long, and is one of the nearest to Europe, being ratherunder 900 miles from the coast of Portugal, from which it isseparated by an ocean 2,500 fathoms deep. The depth betweenthe islands does not seem to be known, but the 1,000 fathomline encloses the whole group pretty closely, while a depth ofabout 1,800 fathoms is reached within 300 miles in all direc-tions. These great depths render it in the highest degree 240 ISLAND LIFE. [part ii. improbable that the Azores have ever been united with theEuropean continent; while their being wholly volcanic isequally opposed to the
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