Geology of Upper Illinois. 147 
and the canal, it is intended, by means of a short cut across the 
bottoms in the direction of the dotted lines, (v on the map,) to 
admit boats from the river; and thus at a trifling expense, to con- 
vert it into a steam-boat basin. An dmprovement of this nature 
will have its value greatly enhanced, arising out of the mineral re- 
sources so remarkably accumulated at this point, the future devel- 
opment of which is destined to confer upon Rockwell numerous 
commercial and manufacturing advantages. 
It is within a few rods only of the eastern extremity of the Con- 
sogin basin, that the largest out-crop of coal in the valley of the 
Illinois occurs. By a reference to our map, a ravine will be no- 
ticed as descending from the high prairie, at a distance of about 
seventy rods from the eastern boundary of Rockwell. | This is 
the Swanson ravine. Its bed is entirely within the coal strata, 
and very nearly conforms in direction to their basseting edges. 
The slopes of the ravine consist superficially, to a considerable 
extent, of soil and loose materials. Slight excavations however, 
are all that is requisite to reveal the strata, which, on the west side 
at least, are uniform and continuous up the valley. Commencing 
at the mouth of the ravine on its western side, we have a good 
view of the position of the coal-bed, where it has been partially 
laid open, for supplying to some extent fuel to the vicinity, espe- 
cially for blacksmithing purposes. The following section was ta- 
ken at the locality, from the top downwards :— 
50 to 60 feet of the superior slope, concealed by soil. 
‘43 feet gray marly slate-clay. 
- A inches argillo-calcareous iron ore. 
8 “ — gray marly slate. 
1 foot 4 inches limestone. 
1 ‘* black bituminous slate. 
2" - gray marly slate-clay. 
6 coal. 
This i se the coal-stratum nearly to the bottom of the ravine, 
in which however, a well has been sunk, thereby making us ac- 
aeimiodwiths the strata for a depth of at least thirty feet more 
howin of blue and gray slate-clays. The 
dip of the coal and its associated layers is W. S. W. at an angle 
between 15 and 20°. 
»» As the State owns the section on which this coal opening oc- 
curs, no farther labor has been expended with a view to trace the 
