chap, xii.] OCEANIC ISLANDS. 239 
afford evidence of the highest value as to the means of dispersal 
of various groups of organisms across a wide expanse of ocean. 
THE AZOBES, OE WESTEEN ISLANDS. 
These islands form a widely scattered group, nine in number, 
situated between 37° and 39° 40' N. Lat. and stretching in 
a south-east and north-west direction over a distance of nearly 
OUTLINE MAP OF THF. AZOEE8. 
Note.— T he light tint shows where the sea is less than 1,000 fathoms deep. 
The 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 forty 
miles long, and is one of the nearest to Europe, being rather 
under 900 miles from the coast of Portugal, from which it is 
separated by an ocean 2,500 fathoms deep. The depth between 
the islands does not seem to be known, but the 1,000 fathom 
line encloses the whole group pretty closely, while a depth of 
about 1,800 fathoms is reached within 300 miles in all direc- 
tions. These great depths render it in the highest degree 
