206 
IOWA ACADEMY OP SCIENCE 
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GROUPING OP THE CEDAR VALLEY LIMESTONES. 
Lucas 
Limestone. 
XI. 
Feet. 
Limestone, white, fine-grained, StraparoUus abun- 
dant at base 20 
Coralville 
Limestone. 
Rapid 
Limestone. 
10. Limestone, gray, fine-grained, ( Idiostroma ) 2 
9. Limestone, gray, earthy. 6 
8. Limestone, gray, massively bedded, ( Acervularia 
and sponges.) 10 
7. Limestone, bluish, thin-bedded and shaly, unfossil- 
iferous 8 - 
6. Limestone, gray massive, compact, coralline 2 
5. Limestone, bluish, heavily bedded, (Cladopora) . . . 3 
4. Limestone, blue, massive compact, (Cystiphyllum) . 6 
3. Limestone, gray, shaly, unfossiliferous 20 
Solen 
Limestone. 
2. Limestone, gray, shaly, ( Megistocrinus ) 
1. Limestone, bluish, compact, ( Phillipsastrea ) 
15 
10 
The several terranes are fully described in the report on Johnson 
county. The point here to be especially noted is that subdivisions recog- 
nized should receive greater emphasis than they are likely to from mere 
perusal of the Calvin report. By definitely designating them by means 
of local names where the sections are best displayed this is partially 
accomplished. 
