s mind. One of the most curious cases which he
adduces seems to me to be the two allied fresh-water, highly peculiar
porpoises in the Ganges and Indus; and the more distantly allied form
of the Amazons. Do you remember his explanation of an arm of the sea
becoming cut off, like the Caspian, converted into fresh-water, and then
divided into two lakes (by upheaval), giving rise to two great rivers.
But no light is thus thrown on the affinity of the Amazon form. I now
find from Flower's paper (384/3. "Zoolog. Trans." VI., 1869, page 115.
The toothed whales are divided into the Physeteridae, the Delphinidae,
and the Platanistidae, which latter is placed between the two
other families, and is divided into the sub-families Iniinae and
Platanistinae.) that these fresh-water porpoises form two sub-families,
making an extremely isolated and intermediate, very small family. Hence
to us they are clearly remnants of a large group; and I cannot doubt
we here have a good instance precisely like that of ganoid fishes, of a
large ancient marine group, preserved exclusively in fresh-water, where
there has been less competition, and consequently little modification.
(384/4. See Volume I., Letter 95.) What a grand fact that is which
Miquel gives of the beech not extending beyond the Caucasus, and then
reappearing in Japan, like your Himalayan Pinus, and the cedar of
Lebanon. (384/5. For Pinus read Deodar. The essential identity of the
deodar and the cedar of Lebanon was pointed out in Hooker's "Himalayan
Journals" in 1854 (Volume I., page 257.n). In the "Nat. History Review,"
January, 1862, the question is more fully dealt with by him, and the
distribution discussed. The nearest point at which cedars occur is the
Bulgar-dagh chain of Taurus--250 miles from Lebanon. Under the name of
Cedrus atlantica the tree occurs in mass on the borders of Tunis, and as
Deodar it first appears to the east in the cedar forests of Afghanistan.
Sir J.D. Hooker supposes that, during a period of greater cold, the
cedars on the Taurus and on Lebanon lived many thousand feet nearer the
sea-level, and spread much farther to the east, meeting similar belts
of trees descending and spreading westward from Afghanistan along the
Persian mountains.) I know of nothing that gives one such an idea of the
recent mutations in the surface of the land as these living "outlyers."
In the geological sense we must, I suppose, admit that every yard of
land has been successively cov