264 Essay, Ge. 
but of immense size, and strewed promiscuously 
in the basin of tbe river ; they appeared to forin 
in this point, the western boundary of the tract, 
which, beyond the river, was met again bya hill 
descending from the grand central ranges in this 
direction. 
The western banks of the river were confined 
‘by several ridges of moderate elevation; at the 
spot which I examined, a.pile, of a somewhat 
pyramidal form, rose precipitously to the height 
of several hundred feet: the side near the river 
was completely naked, and exhibited its internal 
constitution. Ac the base a rugged mass pro- 
jected, which at a distance resembled Lava, but 
on near examination was found to be an aggre- 
gate rock of a grey color, consisting of sand,* 
calcareous spar, and clay in various proportions 
of admixture: extensive groupes of spar ap- 
peared on the surface and on the fragments 
which were broken off: detached masses of a 
similar rock were afterwards found on the op- 
posite side ei the river, which were more com- 
pact, and in 
they ccs chiefly of nodules of « clay, sus 
ded in a sparry mass. Resting on the dps 
gate Brey rock at the base, and composing the 
: of this eminence, was an extensive 
Seabee consisting entirely of a deposition 
from water, of great variety of configurationand 
arrangement, but chicfly of lamina and nodules. 
The whole side of the hill which was exposed 
exhibited this deposition in a nodular or tabu- 
Jar form, in groupes akernating with or mixed 
- Exp. Cat. No. 34. 
tf Exp. Cat. No. 37. 
