140 
BANKS OF PETRIFIED SHELLS. 
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 ot 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. 
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 different in character and substance from any we had 
as yet seen. They approached a dirty yellow-ochre in co- 
lour, that became brighter in hue as it rose, and, instead of 
being perforated, were compact and hard. The waters of the 
river had, however, made horizontal lines upon their fronts, 
which distinctly marked the rise and fall of the river, as the 
strength or depth of the grooves distinctly indicated the 
levels it generally kept. It did not appear from these lines, 
that the floods ever rose more than four feet above the then 
level of the stream, or that they continued for any length 
of time. On breaking off pieces of the rock, we ascertained 
that it was composed of one solid mass of sea-shells, of various 
kinds, of which the species first mentioned formed the lowest 
part. 
