Geology of Upper Illinois. 155 
We shall now treat of the economical value of the coal to this 
region. Bituminous coal is valuable in every part of our country ; 
but to a rich prairie section, where the climate in winter is se- 
vere, and where wood is scarcely abundant enough to supply ma- 
terials for fencing and building, its importance is almost incapable 
of being ex 
The deposit, aa which main reliance is likely to be placed 
for coal, at least for a considerable time to come, is the stratum 
which crops out in the Swanson ravine. This bed will probably 
be found workable under the entire tract, bounded by the ravine 
on the east and the Little Vermilion on the west. At what depth 
below the surface it will be found, situated on the western por- 
tion of this tract, it is of course impossible to say ; but from what 
is known of coal-fields in other countries, we are authorized in 
believing that as the bed is worked down, its present pitch will 
alter, and that at no great distance from the ravine it will assume 
a horizontal position. 
The thin horizontal bed of coal which has been opened at so 
many points between Utica and Ottawa, and which is worked at 
several openings near the latter place, is undoubtedly capable of 
furnishing a large supply of this fuel... But the difference of ex- 
pense in: working a thin and a thick stratum is so great, especially 
where the thin bed, as in the present instance, is horizontal in po- 
sition, and overlaid by a vast accumulation of fissile strata, that it 
gives to the main deposit an obvious superiority. It is plain, 
therefore, that the canal commissioners have judged correctly, in 
affixing a high valuation to the coal-mines of the state on section 
thirteen. 
The coal at Vermilionville, besides being a number of miles 
from navigable water, is so situated, with regard to the bed of 
the river in which it occurs, as to render its exploration unu- 
sually inconvenient and expensive. It will not, therefore, be 
likely to come into market, until the supply near the canal and 
the Illinois river has been to a degree exhausted. No coal is ob- 
tained from down the river short of Henry; nor even at this place 
within several miles of the river. : 
It appears quite certain therefore, that Chicago and the region 
bordering on the upper lakes are destined, on the completion of 
the canal, to receive their bituminous fuel very largely from Rock- 
well and its immediate vicinity, since there is little prospect of 
