If now we consider the extreme remoteness and isolation of these islands, their small area and comparatively recent origin, and that, notwithstanding all these disadvantages, they have acquired a very considerable and varied flora and fauna, we shall, I think, be convinced, that with a larger area and greater antiquity, mere separation from a continent by many hundred miles of sea would not prevent a country from acquiring a very luxuriant and varied flora, and a fauna also rich and peculiar as regards all classes except terrestrial mammals, amphibia, and some groups of reptiles. This conclusion will be of great importance in those cases where the evidence as to the exact origin of the fauna and flora of an island is less clear and satisfactory than in the case of the Azores and Bermuda. * * * * * {275} CHAPTER XIII THE GALAPAGOS ISLANDS Position and Physical Features--Absence of Indigenous Mammalia and Amphibia--Reptiles--Birds--Insects and Land-Shells--The Keeling Islands as Illustrating the Manner in which Oceanic Islands are Peopled--Flora of the Galapagos--Origin of the Flora of the Galapagos--Concluding Remarks. The Galapagos differ in many important respects from the islands we have examined in our last chapter, and the differences are such as to have affected the whole character of their animal inhabitants. Like the Azores, they are volcanic, but they are much more extensive, the islands being both larger and more numerous; while volcanic action has been so recent that a large portion of their surface consists of barren lava-fields. They are considerably less distant from a continent than either the Azores or Bermuda, being about 600 miles from the west coast of South America and a little more than 700 from Veragua, with the small Cocos Islands intervening; and they are situated on the equator instead of being in the north temperate zone. They stand upon a deeply submerged bank, the 1,000 fathom line encircling all the more important islands at a few miles distance, whence there appears to be a comparatively steep descent all round to the average depth of that portion of the Pacific, between 2,000 and 3,000 fathoms. {276} [Illustration: MAP OF THE GALAPAGOS AND ADJACENT COASTS OF SOUTH AMERICA.] The light tint shows where the sea is less than 1,000 fathoms deep. The figures show the depth in fathoms.