The peculiar feature in the population of the
whole series of secondary strata, was the prevalence
of numerous and gigantic forms of Saurian
reptiles. Many of these were exclusively marine
; others amphibious; others were terrestrial,
ranging in savannahs and jungles, clothed with a
tropical vegetation, or basking on the margins of
estuaries, lakes, and rivers. Even the air was
tenanted by flying lizards, under the dragon
each other’s peculiar condition.” With respect to the final
cause of these peculiarities, he conjectures that they have relation
to an inferior condition of the brain and nervous system in
the Marsupialia; and considers the more protracted period of
viviparous utero-gestation in the higher orders of Mammalia to
be connected with their fuller developement of the parts subservient
to the sensorial functions ; the more simple form, and inferior
condition of the brain in Marsupialia, being attended with a
lower degree of intelligence, and less perfect condition of the
organs of voice.
As this inferior condition of living Marsupialia shows this
order to hold an intermediate place between viviparous and oviparous
animals, forming, as it were, a link between Mammalia
and Reptiles; the analogies afforded by the occurrence of the
more simple forms of other classes of animals in the earlier geological
deposits, would lead us to expect also that the first forms
of Mammalia would have been Marsupial.
In a recent letter to myself, Mr. Owen adds the following interesting
particulars respecting the physiology of this remarkable
class of animals. “ Of the generality of the law, as regards the
simple unconvoluted form of the cerebrum in the Marsupials, I
have had additional confirmation from recent dissections of a
Dasyurus and Phalangista. With an organization defective in
that part which I believe to be essential to the docility pf the
horse, and sagacity of the dog, it is natural to suppose that the
Marsupial series of warm-blooded quadrupeds would be insufform
of Pterodactyles. The earth was probably
at that time too much covered with water, and
those portions of land which had emerged above
the surface, were too frequently agitated by
earthquakes, inundations, and atmospheric irregularities,
to be extensively occupied by any
higher order of quadrupeds than reptiles.
As the history of these reptiles, and also that
of the vegetable remains,* of the secondary forficient
for the great purposes of the Creator, when the earth was
rendered fit for the habitation of man. They do, indeed, afford
the wandering savages of Australia a partial supply of food; but
it is more than doubtful that any of the species will be preserved
by civilized man on the score of utility. The more valuable and
tractable ruminants are already fast encroaching on the plains
where the kangaroo was once the sole representative of the
graminivorous Mammalia.
“ It is interesting, however, to observe, that the Marsupials,
including the Monotremes, form a very complete series, adapted
to the assimilation of every form of organic matter; and, no
doubt, with enough of instinctive precaution, to preserve themselves
from extermination, when surrounded with enemies of no
higher intellectual powers than the Reptilia. It would, indeed,
be a strong support to the consideration of them as a distinct
ovoviviparous sub-class of Mammals, if they should be found,
as hitherto, to be the sole representatives of the highest class
of Vertebrata, in the secondary strata.”—R. Owen.
* The vegetable remains of the secondary strata differ from
those of the transition period, and are very rarely accumulated
into beds of valuable coal. The imperfect coal of the Cleveland
Moorlands near Whitby, on the coast of Yorkshire, and that of
Brora in the county of Sutherland, occurs in the lower region of
the oolite formation; that of Biickeberg in Nassau, is in the
upper region of the same formation, and is of superior quality.