94 GEOLOGICAL RECONNOISSANCE 
ing character of the sur- 
face, together with the 
interspersed groves of 
timber, break the other- 
: wise monotonous ap- 
eae pearance of some of those 
tt; prairiescenes. The prai- 
TE | | cormzseznred and sabrrtine mem) ie gil, both of the Mar- 
shall and Huzza prairies, 
is derived in part from 
| the disintegration of’ the 
s [8s , subearboniferous _ limie- 
| ‘stone, sandstones, and 
y shale of the preceding 
“s [8 | 60; | Sandstone. | section, and in part of 
Pir the cherty limestone on 
which itis based. Where 
the soil is mostly, or ex- 
clusively, derived from 
the latter, it usually pro- 
duces land supporting 
stunted oaks, less rich 
than the preceding soil, 
and not'so well adapted 
for wheat, but excellent 
for oats. 
Light grey cherty limestone. The descent from Mar- 
, shall’s prairie to Crook- 
ed creek, is 230 feet, most- 
ly over chert derived 
‘SECTION OF BOAT MOUNTAIN—Conrinvzp. 
Inches. 
| Feet. 
Black bituminous shale with segregations 
and septaria.- 
Sandstone. 
from the equivalent of the light-grey cherty limestone, that underlies the 
black bituminous shale, at the base of the Boat mountain. Between 
Marshall’s and the Huzza prairies, 100 to 200 feet of sandstone was passed 
over, interstratified amongst the limestone. 
The ascent from the Big spring, on Crooked creek, to the Baker prairie, 
is 270 feet. The light-grey limestone is here again exposed with segre- 
gations of chert, and with some encrinites imbedded ; but the species were 
not distinguishable. 
One and a half miles south-east of Charles Hutchison’s farm, the fol- 
lowing succession was observed in a ravine: 
