138 CEMENT MATERIALS AND INDUSTRY. I bull. 243JI* 
made up of bluish thin-bedded limestones in terbedded with soft bluish- 
green calcareous shales. Toward the top of the series massive sandy 
limestone beds, brownish in color, occur. a 
COMPOSITION. 
No analyses of the limestones and shales of this series from Indians 
localities are available, but on pages 173 and 270 will be found a num- 
ber of analyses of similar materials from adjoining areas in Ohio anc 
Kentucky. 
MISSISSIPPIAN ("LOWER CARBONIFEROUS") LIMESTONES AND SHALEs||^ 
As shown on the geologic map, PI. XII, the Mississippian rocks occu 
in Indiana in a belt averaging 20 miles or more in width and extend 
ing from Ohio River in a general northwesterly direction to th 
Indiana-Illinois line. Another area underlies Elkhart, Lagrange, and 
St. Joseph counties, in the extreme northern part of the State. 
The Mississippian rocks as thus mapped include several distinct 
formations. Beginning at the top there are (a) Kaskaskia group 
sandstones, shales, and limestones; (b) Mitchell limestone; (c) Bedforc 
oolitic limestone; (d) Harrodsbnrg limestone; (e) Knobstone group 
shales and shaly sandstones. 
KASKASKIA OR HURON GRO UP. 
These rocks are from 100 to 150 feet thick and are immediate! 
overlain by the heavy Mansfield sandstone of the Coal Measures. Th 
group includes several beds of limestone interbedded with sandstones : 
and shales. In view of the nearness of the thick and valuable Mitchel 
and Bedford limestones it seems improbable that the limestones o 
the Kaskaskia group will become of importance as cement materials. 
MITCHELL FORMA TION. 
This formation, lying below the Kaskaskia group and above th 
Bedford limestone, is a thick series of limestones with occasional thi 
beds of shale. The series varies in thickness from 150 to 250 feet. 
BEDFORD LIMESTONE. 
This formation varies in thickness from 30 to 90 feet, or even less, 
the greater thicknesses being in the area from Bedford to Salem.* 
The Bedford limestone is the well-known oolitic rock — a creamyl 
white limestone, soft when freshly quarried, but hardening rapidly 
on exposure. 
HARRODSBURG LIMESTONE. 
Underlying the Bedford limestone is the Harrodsburg limestone, a 
series ranging from 30 to 100 feet in thickness and made up mostly- 
of limestones, with occasional thin beds of shale. 
« These occur so seldom (only locally in Clark and Jefferson counties) that the fact is hardly worth 
mentioning. The lower 200 feet consist almost entirely of shale, and in the next 200 feet the lime-] 
stones are more abundant than in other parts of the series. 
