ts are made for the
benefit of the reader.

"The general result arrived at is that the great northern continents
represent the original seat of mammalian life and the regions of its
highest development.... The tertiary fauna of North America, compared with
that of Europe, exhibits proofs of a former communication between the two
northern continents both in the North Atlantic and North Pacific, but
always, probably, in rather high latitudes. This is indicated both by the
groups which appear to have originated in one continent and then to have
passed across to the other and also by the entire absence from America of
many important groups which abounded in Europe (and _vice versa_)
indicating that the communication between the two hemispheres was always
imperfect and of limited duration.... On the other hand, the marked
continuity of the Northern Flora (with only a gradual east and west change
in the arctic regions, but with an increased divergency southwards)
requires it to be treated as a whole, although it has long been divided
into that of the old and new world by the severance of North America from
Northern Asia and by the barrier to an interchange of vegetation in the
upheaval of the Rocky Mountain range. The old and new world divisions of
the flora which, no doubt, began to diverge from the mere influence of
distance, have now had that divergence immensely increased by
isolation.... Large American genera (of the intermediate flora) have sent
off offsets into Eastern Asia which, gradually diminishing in number of
species and sometimes slightly modifying their character, have spread over
the whole of Asia and invaded almost every part of Europe.... With regard
to the arctic alpine flora, Hooker found that, estimating the whole arctic
flora at 762 species, arctic East America possessed 379 of which 269 are
common to Scandinavia. Of the whole flora 616 species are found in arctic
Europe and of these 586 are Scandinavian and this leads Hooker to the
striking observation that 'the Scandinavian flora is present in every
latitude of the globe and is the only one that is so.' According to
Bentham, Scandinavia, which would, according to older rules, have been
termed the centre of creation for the arctic regions, may now be termed
the chief centre of preservation within the arctic circle owing, perhaps,
to its more broken conformation and partly to that warmer climate ...
which was, during the glacial period a means of preserva