and
animal life in the morning time of the earth, of the causes and results
of the glacial period, and of the manner of reckoning the age of the
world from geological data. It also included several new features of
natural science, and still retains an important place in scientific
literature. No better summary can be given than that by the author
himself:

In my "Geographical Distribution of Animals" I had, in the first place,
dealt with the larger groups, coming down to families and genera, but
taking no account of the various problems raised by the distribution of
particular _species_. In the next place, I had taken little account of
the various islands of the globe, excepting as forming sub-regions or
parts of sub-regions. But I had long seen the great interest and
importance of these, and especially of Darwin's great discovery of the
two classes into which they are naturally divided--oceanic and
continental islands. I had already given lectures on this subject, and
had become aware of the great interest attaching to them, and the great
light they threw upon the means of dispersal of animals and plants, as
well as upon the past changes, both physical and means of dispersal and
colonisation of animals is so connected with, and often dependent on,
that of plants, that a consideration of the latter is essential to any
broad views as to the distribution of life upon the earth, while they
throw unexpected light upon those exceptional means of dispersal which,
because they are exceptional, are often of paramount importance in
leading to the production of new species and in thus determining the
nature of insular floras and faunas.

Having no knowledge of scientific botany, it needed some courage, or, as
some may think, presumption, to deal with this aspect of the problem;
but ... I had long been excessively fond of plants, and ... interested
in their distribution. The subject, too, was easier to deal with, on
account of the much more complete knowledge of the detailed distribution
of plants than of animals, and also because their classification was in
a more advanced and stable condition. Again, some of the most
interesting islands of the globe had been carefully studied botanically
by such eminent botanists as Sir Joseph Hooker for the Galapagos, New
Zealand, Tasmania, and the Antarctic islands; Mr. H.C. Watson for the
Azores; Mr. J.G. Baker for Mauritius and other Mascarene islands; while
there were floras by competen