50 GEOLOGICAL RECONNOISSANCE 
SECTION OF MARION COUNTY—Centinvep. 
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42 —\Bench of grey magnesian limestone. 
‘ 2 4 
iL |Thin-bedded, light-colored magnesian| 
31, | mn mi | Hmestone. 12 
‘mi mu |Bench of solid, grey magnesian limest. 
20) |__ ML i 
ML ML 
__MUL _|Thin-bedded magnesian limestone, in 
ML ML|_ beds of a few inches in thickness, ex- 
err? tending down into the bed of Sugar| 
Loaf creek. 
ML ML 
ML 
ML ML 20 
307 
Three quarters of a mile south of the Mitchell farm, the following sec- 
tion was obtained in a hill known as “ Mitchell’s Hill:” 
Height. : Thickness. 
a Sn ey 
148 feet. : : 
142 « Top of the loose pieces of chert and sandstone--..+--- 6 
Hard, light-grey magnesian limestone, with occasional 
beds of chalcedonic chert, most abundant in the 
76 +6 lower part seers cree eee eee eee eee ee eee eee eee 76 
5G Quartzose sandstone and chert----+ ++ sees ee eee eens 10 
26 « Magnesian limestone +++ este ee rece cee eee eee eens 40 
25 “  Intercalated bed of siliceous magnesian limestone: ---- 1 
5 Magnesian limestone, with red and yellow bands--.--. 15 
Slope and bank extending down to the bed of upper 
0 Sugar-loaf creek- bs hs ios ties Wis saiet gts Gta ele" te ak ahaa’ toner ahs 0 
Plate 3 represents a distant view of Sugar-loaf hill, of ene a 
conspicuous land-mark, lying in the eastern part of Sugar-loaf prairie. 
This hill is 800 feet above the level of Sugar-loaf creek, near the Coka 
farm. 
It is composed of thin-bedded magnesian limestones, overlaid by chert 
at top, and underlaid by light-colored earthy limestone, like the so-called 
“Cotton Rock,” of Missouri. 
A voluminous spring issues from the cavernous spaces in the rocks on 
the east side of lower Sugar-loaf creek, affording a valuable water-power, 
available at all seasons of the year, with but little variation as to quantity 
