106 REMARKABLE BOULDERS IN THE HAWKESBURY ROCKS. 
The shales contain numerous small fragments of ferns, which 
are in a very remarkable state of preservation. I am collecting 
and figuring some of these, with the object of laying them before 
the Society on another occasion. 
In the sections exposed in the quarries at Fort Macquarie, 
Woolloomooloo, Flagstaff Hill, and other places, may be seen 
boulders af the shale of all sizes up to 20 feet in diameter, 
embedded in the sandstone in a most confused manner, some of 
been derived. These angular boulders occur nearly always im- 
mediately above the shale-beds, and are mixed with very rounded 
pebbles of quartz; they are sometimes slightly curved, as though 
they had been bent whilst in a semi-plastic condition, and the 
shale-beds occasionally terminate abruptly, as though broken off 
Had the boulders of soft shale been deposited in their 
position by running water alone, their form would have been 
rounded instead of angular. It would appear that the shale-beds 
must have been partly disturbed by some such agency as that of 
ulders, occur a few rounded pebbles of shale, showing that fe 
currents had swept along for some distance a few of the 
_ fragments until they had become rounded. These pebbles are 
usually oval in shape, and are embedded in such a manner that 
the longer axis of the pebble is nearly always inclined, or dips, 
towards the 8.W., thus indicating that the transporting 
had chiefly come from that direction; whereas the angular 
_ boulders in the beds below are, as before mentioned, confusedly 
size. 
These boulder accumulations occur in irregular patches a 
to the Indian Geological Survey ; and near the Lawson ee 
station Mr. Thomas Brown, J.P., of Eskbank, 0 ' 
: is granulatus, Egerton. v. 
fsh, Ayriolepia Clariei, Egerton, was found by the late Be 
From their lithological character, the Hawkesbury Rok ae : 
to have been formed in a comparatively shallow sea W ; 
