more lofty
mountains, mountains, 1859 1860 1861 1866 | mountains 1869 1872 |
and on the temperate lowlands and on the temperate lowlands 1859 1860 1861 1866 |
OMIT 1869 1872 |
of the
northern and southern hemispheres, are sometimes identically northern and southern hemispheres, are sometimes identically 1859 1860 1861 1866 |
tropics in all parts of the world, and on the temperate plains of the north and south, are either 1869 1872 |
the
same; same; 1859 1860 1861 1866 | same 1869 1872 |
but they are much oftener specifically distinct, though related to each other in a most remarkable manner. but they are much oftener specifically distinct, though related to each other in a most remarkable manner. 1859 1860 1861 |
but much oftener they are specifically distinct, though plainly related to each other in a remarkable manner. 1866 |
identical species or varieties of the same species. 1869 |
species or varieties of the same species. 1872 |
↑2 blocks not present in 1859 1860 1861 1866; present in 1869 1872 | It should, however, be observed that these plants are not strictly Arctic
forms; for, as Mr. H. C. Watson has remarked, "in receding from polar towards equatorial latitudes, the Alpine or mountain floras really become less and less Arctic."
Besides these identical and closely allied forms, many species inhabiting the same widely sundered areas, belong to genera not now found in the intermediate tropical lowlands.
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This This 1859 1860 1861 1866 | These 1869 1872 |
brief
abstract applies abstract applies 1859 1860 1861 1866 | remarks apply 1869 1872 |
to plants
alone: alone: 1859 1860 1861 1866 | alone; 1869 1872 |
some strictly some strictly 1859 1860 1861 1866 |
but some few 1869 1872 |
analogous facts could be given
on the distribution of on the distribution of 1859 1860 1861 1866 |
in regard to 1869 1872 |
terrestrial animals. In marine productions, similar cases
occur; occur; 1859 1860 1861 1866 | likewise occur; 1869 1872 |
as an example, I may quote a
remark remark 1859 1860 1861 1866 | statement 1869 1872 |
by the highest authority, Prof. Dana, that
"it "it 1859 1860 1866 1869 1872 | "it 1861 |
is certainly a wonderful fact that New Zealand should have a closer resemblance in its crustacea to Great Britain, its antipode, than to any other part of the
world." world." 1859 1860 1866 1869 1872 | world." 1861 |
Sir J. Richardson, also, speaks of the reappearance on the shores of New Zealand, Tasmania,
&c., &c., 1859 1860 1866 1869 1872 | &c, 1861 |
of northern forms of fish. Dr. Hooker informs me that twenty-five species of Algæ are common to New Zealand and to Europe, but have not been found in the intermediate tropical seas. ↑5 blocks not present in 1859 1860 1861 1866; present in 1869 1872 | From the foregoing facts, namely
the presence of temperate forms on the highlands across the whole of equatorial Africa, and along the Peninsula of India
to Ceylon and the Malay archipelago,
and in a less well-marked manner across the wide expanse of tropical South America, it appears almost certain that at some former period, no doubt during the most severe part of the
Glacial period, the lowlands of these great continents were everywhere tenanted under the equator by a considerable number of temperate forms.
At this period the equatorial climate at the level of the sea was probably about the same with that now experienced at the height of from five to six thousand feet under the same latitudes,
or perhaps even rather cooler.
During this, the coldest period, the lowlands under the equator must have been clothed with a mingled tropical and temperate vegetation, like that described by Hooker as growing luxuriantly at the height of from four to five thousand feet on the lower slopes of the Himalaya, but with perhaps a still greater preponderance of temperate forms.
So again,
on
the mountainous island of Fernando Po, in the Gulf of Guinea, Mr. Mann found temperate European forms beginning to appear at the height of about five thousand feet.
On the mountains of Panama, at the height of only two thousand feet, Dr. Seemann found the vegetation like that of Mexico, "with forms of the torrid zone harmoniously blended with those of the temperate."
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It should be observed that the northern
species and species and 1859 1860 1861 | species and 1866 |
forms found
in
the
southern parts southern parts 1859 1860 1861 | mountain-ranges 1866 |
of the
southern hemisphere, and on the mountain-ranges of the southern hemisphere, and on the mountain-ranges of the 1859 1860 1861 |
OMIT 1866 |
intertropical
regions, regions, 1859 1860 1861 | regions 1866 |
are not arctic, but belong to are not arctic, but belong to 1859 1860 1861 |
and in 1866 |
the
northern northern 1859 1860 1861 | southern 1866 |
temperate temperate 1859 1860 1861 |
parts of the southern hemisphere are not arctic, but belong to the temperate 1866 |
zones. zones. 1859 1860 1861 | zones: 1866 |
As
Mr. H. C. Watson has recently remarked,
"In "In 1859 1860 | "In 1861 | "in 1866 |
receding from polar towards equatorial latitudes, the Alpine or mountain floras really become less and less
arctic." arctic." 1859 1860 1866 | arctic." 1861 |
Many of the forms living on the mountains of the warmer regions of the earth and in the southern hemisphere are of doubtful value, being Many of the forms living on the mountains of the warmer regions of the earth and in the southern hemisphere are of doubtful value, being 1859 1860 |
Many of the forms living on the mountains of the warmer reigons of the earth and in the southern hemisphere are of doubtful value, being 1861 |
Of these forms, some few are identical with northern temperate species, or are varieties of them, whilst others are 1866 |
ranked by
some some 1859 1860 1861 | all 1866 |
naturalists as
specifically distinct, by others as varieties; but some are certainly identical, and many, though closely related to northern forms, must be ranked as distinct species. specifically distinct, by others as varieties; but some are certainly identical, and many, though closely related to northern forms, must be ranked as distinct species. 1859 1860 1861 |
closely allied to, but specifically distinct from, their northern representatives. 1866 |
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Now let us see
what light can be thrown what light can be thrown 1859 1860 1861 1866 |
whether Mr. Crolls conclusion that when the northern hemisphere suffered from the extreme cold of the great Glacial period, the southern hemisphere was actually warmer, throws any clear light 1869 |
whether Mr. Croll's conclusion that when the northern hemisphere suffered from the extreme cold of the great Glacial period, the southern hemisphere was actually warmer, throws any clear light 1872 |
on the
foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was during the Glacial period simultaneously much colder than at present. foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was during the Glacial period simultaneously much colder than at present. 1860 1861 |
foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was during the Glacial period simulta- neously much colder than at present. 1859 |
foregoing facts, on the belief, supported as it is by a large body of geological evidence, that the whole world, or a large part of it, was simultaneously colder during the Glacial period than at present. 1866 |
present apparently inexplicable distribution of various organisms in the temperate parts of both hemispheres, and on mountains of the tropics. 1869 |
present apparently inexplicable distribution of various organisms in the temperate parts of both hemispheres, and on the mountains of the tropics. 1872 |
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