THE MIDDLE COAL MEASURES 583 
Feet Inches 
g. Shale, yellow, sandy, with marked horizontal bedding 
planes, - - - - - - - - - 4 
8. Shales, black to drab, carbonaceous, - . - 6 
7. Limestone, nodular, sandy, with Productus cora, Chonetes 
mesoloba and Athyris subtilita, - - - - - I 4 
6. Shale, gray, sandy, - - - - - - 3 
5. Limestone, similar to number 7, - . - - 10 
4. Shale, clayey, drab to blue, - : - - : ie) 
3. Shale, carbonaceous, - - - - - - I 
2. Limestone, thin bedded, leaf-like in texture, with Produc- 
tus muricatus, Chonetes mesoloba, Derbya crassa and Pro- 
ductus costatus, - - - - - - - B 
1. Clay, green, - - . - . - - - 3 
South from here in Clark and Lucas counties the work has 
not yet been carried on in sufficient detail to allow a general 
section to be made out. It is, however, known that there are in 
- the region strata of the same general type as those found in 
Madison, Dallas and Guthrie counties, though probably detailed 
correlation will be impossible. 
Along the southern border of the state the Des Moines beds 
outcrop from the Mississippi River west to Decatur county, 
where they become buried beneath the Bethany. As far west 
as the Chariton River the beds may be referred unhesitatingly to 
the lower division, corresponding, as noted above, with the 
Cherokee shales. Their character is shown in exposures and 
mine sections along the Chicago, Milwaukee and St. Paul Railway 
from Ottumwa southwest. Above these is a formation; includ- 
ing several limestone beds and one widely worked seam of coal, 
which has been called the Appanoose formation.? In general 
character these strata correspond to those seen farther north at 
the same horizon. A generalized section is given below: 
Feet Inches 
17. Limestone, gray, subcrystalline, seen in the railway cut 
near Anchor No. I mine at Centerville, and known among 
the miners as the “floating rock,” —- - - - 2-4 
16. Shale, argillaceous, color variable, - - - 12-30 
tTowa Geol. Surv., Vol. V, Pl. XIV. ?Towa Geol. Surv., Vol. V, pp. 378-394. 
