rrenness. The
most intelligent surveyors of my department have on several occasions
contributed considerably to my collection.

Curiosity led me to investigate some of the fossil remains of those
lately discovered regions while my public duties obliged me to study also
the external features of the country; and I have thus been enabled to
draw some inferences respecting various changes which have taken place in
the surface and in the relative level of sea and land.

The following are the principal rocks which I noticed in the country.

LIMESTONE.

Limestone occurs of different ages and quality presenting a considerable
variety.

1. A light-coloured compact calcareous rock resembling mountain
limestone; at Buree and Wellington, rising, at the former place, to the
height of about 1500 feet above the sea.

2. A dark grey limestone appears at perhaps a still greater height on the
Shoalhaven river; in immediate contact with granite.

3. A crystalline variegated marble is found in blocks a few miles
westward of the above, near the Wollondilly.

4. Another variety of this rock is very abundant in the neighbourhood of
Limestone plains on the interior side of the Coast ranges and near the
principal sources of the Murrumbidgee. This contains corals belonging to
the genus favosites; crinoideae are also found abundantly in the plains
and distinguish this limestone from the others above-mentioned.

These rocks present little or no appearance of stratification.

A remarkably projecting ridge on the banks of Peel's river contained
limestone of so peculiar an aspect as to resemble porphyry, and it was
associated with a rock having a base of chocolate-coloured granular
felspar. (See Volume 1.)

A yellow highly calcareous sandstone, apparently stratified, occurs near
the banks of the Gwydir. Large rounded boulders of argillaceous limestone
have been denuded in the bed of Glendon brook; and an impure limestone is
found in the neighbourhood of William's river, both belonging to the
basin of the Hunter and not much elevated above the sea. Calcareous tuff
or grit may be observed in various localities, and calcareous concretions
abound in the blue clay of almost all the extensive plains on both sides
of the mountains.

A soft shelly limestone, most probably of recent origin though slightly
resembling some of the oolites of England, occurs extensively on the
southern coast between Cape Northumberland and Portland bay where it
for