y
the River Amazon. In the neighbourhood of the Azores, St. Paul's Rocks,
Ascension, and Tristan d'Acunha are considerable areas varying from 1,200
to 1,500 fathoms deep, while the rest of the ridge is usually 1,800 or
1,900 fathoms. The shallower water is no doubt due to volcanic upheaval and
the accumulation of volcanic ejections, and there may be many other deeply
submerged old volcanoes on the ridge; but that it ever formed a chain of
mountains "comparable in elevation with the Andes," there seems not a
particle of evidence to prove. It is however probable that this ridge
indicates the former existence of some considerable Atlantic islands, which
may serve to explain the presence of a few identical genera, and even
species of plants and insects in Africa and South America, while the main
body of the fauna and flora of these two continents remains radically
distinct.

In my _Darwinism_ (pp. 344-5) I have given an additional argument founded
on the comparative height and area of land with the depth and area of
ocean, which seems to me to add considerably to the weight of the evidence
here submitted for the permanence of oceanic and continental areas.

[32] In a review of Mr. T. Mellard Reade's _Chemical Denudation and
Geological Time_, in _Nature_ (Oct. 2nd, 1879), the writer remarks as
follows:--"One of the funny notions of some scientific thinkers meets with
no favour from Mr. Reade, whose geological knowledge is practical as well
as theoretical. They consider that because the older rocks contain nothing
like the present red clays, &c., of the ocean floor, that the oceans have
always been in their present positions. Mr. Reade points out that the first
proposition is not yet proved, and the distribution of animals and plants
and the fact that the bulk of the strata on land are of marine origin are
opposed to the hypothesis." We must leave it to our readers to decide
whether the "notion" developed in this chapter is "funny," or whether such
hasty and superficial arguments as those here quoted from a "practical
geologist" have any value as against the different classes of facts, all
pointing to an opposite conclusion, which have now been briefly laid before
them, supported as they are by the expressed opinion of so weighty an
authority as Sir Archibald Geikie, who, in the lecture already quoted
says:--"From all this evidence we may legitimately conclude that the
present land of the globe, though formed in great measure