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township, the parting runs out nearer the bluffs along the south side of 
Muddy Fork of Silver Creek. From this point westward it is carried 
lower and lower in the hills by the general westward dip of the rocks 
until it passes beneath Blue River. 
It will be noticed that the head waters of Muddy Fork of Silver Creek 
and Blue River overlap by some ten miles, and that the line of parting 
passes to the south of Muddy Fork of Silver Creek and to the north of 
Blue River. - 
The region between these two streams has had its limestone removed 
by their combined erosion. It is interesting to note that this is the only 
locality in the Knobstone region where there is such an overlapping of 
east and west flowing streams. 
The knobs of this locality are formed by a high plateau sloping gently 
to the west, with an abrupt slope to the east,and north on the south side of 
Muddy Fork of Silver Creek, and a steep south slope on the north side. 
The hills immediately north and south of Blue River are less rugged. 
In a general way the lower limit of the group runs in a direction 
somewhat parallel to that of the upper limit, making a slight westward 
bend from block 182 to block 192 of the Illinois grant, where it crosses 
Muddy Fork of Silver Creek and turns to the northeast. 
It will be noticed that the lower limit does not make as great a bend 
to the west as does the upper limit. This is due to the fact that the lower 
limit is very near to the drainage level of the country. In this region the 
lower limit of the Knobstone shale is marked by the greenish Rockford 
Goniatite limestone, which has a thickness of from ten inches to three 
feet. Immediatey below the Goniatite limestone is the Devonian black 
shale. 
Four CoMPARATIVE Cross SECTIONS OF THE KNOBSTONE GRouP OF INDIANA. 
By L. F. BENNETT. 
In connection with the geological work of the State University in 
1897 several cross sections of the Knobstone group were made in order 
that its width and the distribution of the rocks forming it might be dis- 
covered. It is. with four of these comparative cross-sections that this 
paper deals. The elevations were obtained by means of the aneroid bar- 
ometer and the locations by placing and inquiry. As the main object 
