, Juillet, 1832.

[152] Conjectured to be the wild stock of Bos grunniens.

[153] Recollections of a Journey through Tartary, Thibet, and
China (ch. xv. p. 234), by M. Huc. Longman, 1852.

[154] For an account of the more modern changes of the tertiary
fauna and flora of the British Isles and adjoining countries,
and particularly those facts which relate to the "glacial
epoch," see an admirable essay by Prof. E. Forbes. Memoirs of
Geol. Survey of Great Brit. vol. i. p. 336. London, 1846. To
this important memoir I shall have frequent occasion to refer
in the sequel.

[155] See a paper by Charles J. F. Bunbury, Esq., Journ. of
Geol. Soc., London, No. 6, p. 88. 1846.

[156] The Calamites were formerly regarded by Adolphe
Brongniart as belonging to the tribe of Equisetaceae; but he is
now inclined to refer them to the class of gymnogens, or
gymnospermous exogens, which includes the Coniferae and Cycadeae.
Lepidodendron appears to have been either a gigantic form of
the lycopodium tribe, or, as Dr. Lindley thinks, intermediate
between the lycopodia and the fir tribe. The Sigillariae were
formerly supposed by Ad. Brongniart, to be arborescent ferns;
but the discovery of their internal structure, and of their
leaves, has since proved that they have no real affinity to
ferns. According to the view now taken of their structure,
their nearest allies in the recent world are the genera Cycas
and Zamia; while Corda, on the other hand, maintains that they
were closely related to the succulent euphorbias. Stigmaria is
now generally admitted to have been merely the root of
sigillaria. The scalariform vessels of these two genera are not
conclusive in proving them to have a real affinity with ferns,
as Mr. Brown has discovered the same structure of vessels in
Myzodendron, a genus allied to the mistletoe; and Corda has
lately shown that in two species of Stigmaria, hardly
distinguishable by external characters, the vessels of the one
are scalariform, and of the other dotted.

[157] Mr. Lindley endeavored formerly (1834) to show, in the
"Fossil Flora," that Trigonocarpum Noeggerathii, a fruit found
in the coal measures, has the true structure of a palm-fruit;
but Ad. B