surfaces being greater than the supply of water they received. This point
is about 250 or 300 feet above the level of the sea, and if we draw a
line eastward, from the summit of the fossil formation, and prolong it to
the western base of the Blue Mountains, we shall find that it will pass
over the marshes of the several rivers falling into the interior, and
will strike these rivers where their channels appear to fail, as if that
had been the former sea-level.

The impressions I have on this interesting subject are clear enough in my
own mind, but they are difficult to explain, and I fear I have but ill
expressed myself so as to be understood by my readers. I only wish
however to record my own ideas, and if I am in error in any particular, I
shall thank any one of the many who are better versed in these matters
than myself to correct me.

I have stated in a former part of this chapter, that I undertook a
journey to South Australia in 1838. I advert to the circumstance again
because it is connected with the present inquiry. After I had turned the
north-west angle of the Murray, and had proceeded southwards to latitude
34 degrees 26 minutes (Moorundi), where Mr. Eyre has built a residence, I
turned from the river to the westward, along the summit of the fossil
formation, which, at the distance of a few miles, was succeeded by
sandstone, and this rock again, as we gained the hills, by a fine slate,
and this again, as we crossed the Mount Barker and Mount Lofty ranges, by
a succession of igneous rocks, of a character and form such as could not
but betray to a less experienced geologist even than myself the abundant
mineral veins they contained. On descending to the plains of Adelaide I
again crossed sandstone, and to my surprise discovered that the city of
Adelaide stood on the same kind of fossil formation I had left behind me
on the banks of the Murray, and it was on the discovery of this fact that