are not referable to any known extra-Australian genus
of mammals.

2. That the fossils are not referable, from the present evidence, to any
existing species of Australian mammal.

3. That the greater number certainly belong to species either extinct or
not yet discovered living in Australia.

4. That the extinct species of Macropus, Dasyurus, Phascolomys,
especially Macropus atlas and Macropus titan are larger than the largest
known existing species.

5. That the remains of the saltatory animals, as the Macropi, Halmaturi,
and Hypsiprymni, are all of young individuals; while those of the
burrowing Wombat, the climbing Phalanger, and the ambulatory Dasyure, are
of adults.

I remain, dear Sir, etc.

(Signed) Richard Owen.

AGE OF THE BRECCIA CONSIDERED.

Nothing could be discovered in the present state of these caverns at all
likely to throw any light on the history or age of the breccia, but the
phenomena they present seem to indicate more than one change in the
physical outline of the adjacent regions, and probably of more distant
portions of Australia; at a period antecedent to the existing state of
the country.

STATE OF THE CAVERNS.

Dry earth occurred in the floor of both the caverns at Wellington Valley
and in the small chamber (Plate 28) of the breccia cave it was found, as
before stated, beneath the three lines of stalagmite and the osseous
breccia. It seems probable therefore that this earth once filled the cave
also to the same line, and that the stalagmite then extended over the
floor of red earth. Moreover I am of opinion that the interval between
the stalagmite and the roof was partly occupied by the bone breccia of
which portions remain attached to the roof and sides above the line of
stalagmite. It is difficult to conceive how the mass of red earth and
stalagmitic floors could be displaced, except by a subsidence in the
original floor of the cave. But the present floor contains no vestiges of
breccia fallen from the roof, nor any remains of the stalagmitic crust
once adhering to the sides, which are both therefore probably deposited
below the present floor.

In the external or upper part of the same cave, as shown in Plate 45, the
floor consisted of the red dust, and was covered with loose fragments of
rock, apparently fallen from conglomerated masses of limestone and
breccia which also however extended under the red earth there. Thus it
would appear that traces remain in these caverns: Firs