582 FF BAIN AN DRANG EE ONAL 
which is more or less regular in sequence does not correspond 
to the lower portion of the Middle Measures as originally 
described,’ but shows very different succession. 
The Des Moines) beds, “then, imethe centraly portion tofstme 
state consist of a thick mass of shales and sandstones, showing 
no definite order of arrangement which may be recognized over 
any considerable area, covered by more regular sequence of 
which the upper portion may be recognized over a considerable 
area; but as one travels soutn two changes take place. (1) 
The upper member of the section, No. 44, thickness from barely 
thirty feet on the South Raccoon to over seventy feet on Middle 
River near Winterset. (2) The various members of the sec- 
tion thin out and are replaced until in the southeastern portion 
of Madison county none of them can be made out. The section 
immediately below the Bethany limestone in the latter region is 
given below. It will be noticed that while none of the beds of 
the previous section can be recognized, the general character of 
the strata is the same. 
Feet Inches 
22. Shales, drab, argillaceous, with abundant Deréya crassa, 
Chonetes, probably Chonetes parvus Shum, at the top, - 12 
21. Shales, red, argillaceous, - - - - - - 3 
20. Limestone, fragmental, earthly, with bits of fossils, - 2 
Ig. Shale, blue to green, argillaceous, grading into red below, 3 
18. Shales, blue to green, sandy, with nodular segregations 
of limestone, - = : : = 2 : - 1 
17. Shales, blue, calcareous, = = 7 E = 12 
16. Limestone, compact, - & = = = = 2 
15. Limestone, fragmental, loose, with young Chonetes meso- 
loba, - - - - - - - - - ie) 
14. Limestone, fragmental, but firmly cemented, reddish 
color, with Spirifer cameratus and Productus costatus, I 
13. Shales, green, argillaceous, - - - - = 29 
12. Limestone, blue to black, in two ledges, with Spzrdfer 
cameratus, Rhynchonella and Productus, - - I 
Ti. Shale, carbonaceous, - - - = - - 2 
10. Shale, clayey, drab, = = = = = Sey, I 
‘Geol. Polk county, lowa Geol. Sury., Vol. VII, pp. 302-310, and Geol. Iowa 
(White), Vol. I, pp. 272-283. 
