384 
Jukes on Australia. 
of trap rock, which could be traced to have a perfect passage 
from compact tabular or amorphous basalt into hills of solid crys¬ 
talline greenstone. 
In other places quarries were opened in sandstones of the 
pakeozoic age, forming small patches either embosomed in green¬ 
stone, or resting upon it. About a mile from a place called Ralph’s 
Bay Neck, on the S.E. side of North Bay, I found a cliff where 
the sandstones were shown clearly to be posterior to the igneous 
rock. In this case a dark, rudely columnar trap rock ended in a 
succession of small cliffs and terraces in one direction, upon which 
terraces and against which little cliffs rested the sandstone perfectly 
undisturbed, and evidently in the position in which it had been 
originally deposited. 
A parallel instance was observed in the cliff’s a little to the 
eastward of the entrance of Port Arthur. 
It appears then that there are masses of greenstone both of 
more ancient and more modern date than the palaeozoic rocks. 
At Macquarie Plains, about ten miles above New Norfolk 
there is a large exhibition of igneous rock, which from its cellular 
character seems certainly to have flowed as lava in the open air. 
It forms a mass of considerable thickness, as shown in the brooks 
and ravines, and appears to have been gradually accumulated by 
successive accessions of melted matter. I infer this from the fact 
of its including fossil trees, apparently in the position of growth, 
which seem to have been enveloped while living in the lava. 
There are two small patches of tertiary travertinous limestones : 
one mentioned by Mr. Darwin, and found in the outskirts of 
Hobarton, where it appears to have been tilted by the intrusion 
of an adjacent mass of trap ; another in a little cove called 
James’s Bay, about three miles above Hobarton, on the opposite 
side of the Derwent. It rests here nearly horizontally, and is but 
little elevated above the level of the sea. A Helix and a Bulimus, 
and the leaves and portions of the stems of several plants, have 
been found in each locality. 
Fossils from James's Bay. 
Plants, unnamed : one figured by Morris. 
Helix. 
Bulimus. 
