+---------------+-------+-------+-------+------+--------+------+------+ | | | | | Area | | | | | | Area | Mean | Area |penin-| Area | Area | Area | | | total |height,| trunk,|sulas,|islands,|limbs,|limbs,| | | mil. | feet. | mil. | mil. | mil. | mil. | per | | | sq. m.| | sq. m.|sq. m.| sq. m. |sq. m.| cent.| +---------------+-------+-------+-------+------+--------+------+------+ | Old World | 35.8 | 2360 | | | | | | | New World | 16.2 | 2230 | | | | | | | Eurasia | 20.85 | 2620 | 15.42 | 4.09 | 1.34 | 5.43 | 26 | | Africa | 11.46 | 2130 | 11.22 | .. | 0.24 | 0.24 | 2.1 | | North America | 9.26 | 2300 | 6.92 | 0.78 | 1.56 | 2.34 | 25 | | South America | 6.84 | 1970 | 6.76 | 0.02 | 0.06 | 0.08 | 1.1 | | Australia | 3.43 | 1310 | 2.77 | 0.16 | 0.50 | 0.66 | 19 | | Asia | 17.02 | 3120 | 12.93 | 3.05 | 1.04 | 4.09 | 24 | | Europe | 3.83 | 980 | 2.49 | 1.04 | 0.30 | 1.34 | 35 | +---------------+-------+-------+-------+------+--------+------+------+ Islands. The usual classification of islands is into continental and oceanic. The former class includes all those which rise from the continental shelf, or show evidence in the character of their rocks of having at one time been continuous with a neighbouring continent. The latter rise abruptly from the oceanic abysses. Oceanic islands are divided according to their geological character into volcanic islands and those of organic origin, including coral islands. More elaborate subdivisions according to structure, origin and position have been proposed.[29] In some cases a piece of land is only an island at high water, and by imperceptible gradation the form passes into a peninsula. The typical peninsula is connected with the mainland by a relatively narrow isthmus; the name is, however, extended to any limb projecting from the trunk of the mainland, even when, as in the Indian peninsula, it is connected by its widest part. Coasts.