378 @ GALAPAGOS ARCHIPELAGO. {cHaP. XVII. 
height crowned with its crater, and the boundaries of most of 
the lava-streams still distinct, we are led to believe that within a 
period, geologically recent, the unbroken ocean was here spread 
out. Hence, both in space and-time, we seem to be brought 
somewhat near to that great fact—that mystery of mysteries— 
the first appearance of new beings on this earth. 
Of terrestrial mammals, there is only one which must be con- 
sidered as indigenous, namely, a mouse (Mus Galapagoensis), and 
this is confined, as far as I could ascertain, to Chatham island, the 
most easterly island of the group. It belongs, as I am informed 
by Mr. Waterhouse, to a division of the family of mice charac- 
teristic of America. At James island, there is a rat sufficiently 
distinct from the common kind to have been named and described 
by Mr. Waterhouse; but as it belongs to the old-world division 
of the family, and as this island has been frequented by ships for 
the last hundred and fifty years, I can hardly doubt that this rat 
is merely a variety, produced by the new and peculiar climate, 
* food, and soil, to which it has been subjected. Although no one 
has a right to speculate without distinct facts, yet even with 
respect to the Chatham island mouse, it should be borne in mind, 
that it may possibly be an American species imported here; for 
I have seen, in a most unfrequented part of the Pampas, a native 
mouse living in the roof of a newly-built hovel, and therefore its 
transportation in a vessel is not improbable: analogous facts 
have been observed by Dr. Richardson in North America, 
Of land-birds I obtained twenty-six kinds, all peculiar to the 
group and found nowhere else, with the exception of one lark- 
like finch from North America (Dolichonyx oryzivorus), which 
ranges on that continent as far north as 54°, and generally fre- 
quents marshes. The other twenty-five birds consist, firstly, 
of a hawk, curiously intermediate in structure between a Buzzard 
and the American group of carrion-feeding Polybori; and with 
these latter birds it agrees most closely in every habit and even 
tone of voice. Secondly, there are two owls, representing the 
short-eared and white barn-owls of Europe. Thirdly, a wren, 
three tyrant fly-catchers (two of them species of Pyrocephalus, 
one or both of which would be ranked by some ornithologists 
as only varieties), and a dove—all analogous to, but distinct 
from, American species. Fourthly, a swallow, which though 
