246 GEOLOGICAL EEMAEKS. Book II. 
lain over a tract of carboniferous limestone : but, on an 
elevation in this part, a limestone stratum appears of quite 
a different geological character. The chief colour is white, 
softly shaded like marble, or marked with black dendritic 
lines. It is dense, hard, and impregnated with silica, 
which is often secreted in masses of flint. This limestone 
forms at Council Grove a terrace, ascending which the 
road runs, still rising, in a westerly direction. On the 
other side of Diamond Spring, near Lost Spring, com- 
mence the marl and conglomerate strata of the new red 
sandstone. 
I observed no organic remains in the limestone of 
Pleasant Valley and Council Grove ; but, in journeying 
across it, I came to the opinion that one step had brought 
me from the carboniferous limestone to the cretaceous forma- 
tion. At the foot of the terrace formed by these strata, 
just as at the lower edge of the cretaceous strata in Texas, 
clear springs gush forth, the excellent water of which is very 
distinguishable from the peaty water of the strata of coal- 
limestone and the saline or alkaline water of the new red 
sandstone. Marcou, in his geological map of the United 
States, lays down the new red sandstone as commencing 
near Pleasant Valley, with insulated masses of the cre- 
taceous formation lying about on the former. If this is 
the leading feature of this part of the country, the Santa- 
Fe road appears to pass over such a chalk island, which 
exactly covers the limit between the new red sandstone 
and the carboniferous limestone. We travelled through 
part of this country by night, and I could not, therefore, 
follow an uninterrupted line of observation. 
On the Little Arkansas rises an elevation in the prairie, 
the sharp edge of which is formed of layers of light-grey 
sandstone. This termination of a plateau to the north- 
