Though I had not
succeeded in leaving it from Reedy Brook - not having been able to cross
the lava streams of the basaltic table land - I now concluded, from the
nature of the pebbles, and sands of the creek which we had crossed last,
that the basalts and lavas had ceased, and that a passage to the westward
would be practicable.
I followed the Casuarina Creek up to its head, and called it "Big
Ant-hill Creek," in consequence of numerous gigantic strangely buttressed
structures of the white ant, which I had never seen of such a form, and
of so large a size.
The general course of the creek was north-north-west: for the first ten
miles it was without water, but its middle and upper course was well
provided with fine reedy holes, the constant supply of water in which was
indicated by Nymphaeas, and other aquatic plants. At its left side near
the junction I observed, as before mentioned, a coarse grained sandstone,
and, at less than a mile higher up, I found flint rock; and, wherever I
examined afterwards, the rocks proved to be coarse grained granite and
pegmatite, the decomposition of which formed a sandy soil on the slopes,
and clayey flats along the creek.
