We had now arrived at a point at which I hoped to gain some information
from the natives, respecting the sea. It was to no purpose, however, that
I questioned these stupid people. They understood perfectly, by my
pointing to the sky, and by other signs, that I was inquiring about large
waters, but they could not, or would not, give any information on the
subject.

CHANGE IN THE GEOLOGY OF THE COUNTRY.

As we proceeded down the river, its current became weaker, and its channel
somewhat deeper. Our attention was called to a remarkable change in the
geology of the country, as well as to an apparent alteration in the
natural productions. The cliffs of sand and clay ceased, and were
succeeded by a fossil formation of the most singular description. At
first, it did not exceed a foot in height above the water, but it
gradually rose, like an inclined plane, and resembled in colour, and in
appearance, the skulls of men piled one upon the other. The constant
rippling of the water against the rock had washed out the softer parts,
and made hollows and cavities, that gave the whole formation the precise
appearance of a catacomb. On examination, we discovered it to be a compact
bed of shells, composed of a common description of marine shell from two
to three inches in length, apparently a species of turritella.

BANKS OF PETRIFIED SHELLS.

At about nine miles from the commencement of this formation, it rose to
the height of more than 150 feet; the country became undulating, and a
partial change took place in its vegetation. We stopped at an early hour,
to examine some cliffs, which rising perpendicularly from the water, were