244 
IOWA ACADEMY OF SCIENCE 
FEET. INCHES. 
10. Shale, bluish, argillaceous, with calcareous 
seams bearing many pelecypods near top 3 5 
9. Limestone, gray, subcrystalline, with thin 
discontinuous seams of fine-grained sand- 
stone in thin, undulating layers, hearing 
a few small pelecypods 9 
8. Sandstone, fine-grained, rather soft, light 
gray when fresh but weathering yellow- 
ish; in some places with angular chert 
fragments in basal portion 0-2 
(disconformity) 
UPPER ST. Louis: 
7. Limestone, gray, subcrystalline, in rather 
heavy layers; upper surface irregular.... 2i/^-4i^ 
6. Limestone, dark gray, subcrystalline, com- 
pact; often filled with small sinuous, 
tubular, branching fucoids; bearing large 
rounded calcareous algae. 
5. Shale, fissile, bluish when fresh but weather- 
ing drab, becoming more calcareous in 
upper portion 1 
4. Limestone, gray, compact, grading up into 
the bed above 1 
3. Limestone, gray, compact, exhibiting fine 
wavy stratification 
2. Limestone, gray, compact, thin-bedded 1 
1. Limestone, gray, granular to compact, 
locally cross-bedded in part, bearing large 
rounded calcareous algae in upper portion 12 
2-6 
5 
10 
6 
8 
6 
A few rods below the point of the foregoing section, an ex- 
posure in the north bank of the creek along the Chicago, Bur- 
lington and Kansas City railway shows twenty-one feet of Pella 
beds overlain disconformably by five feet of Pennsylvanian sand- 
stone. 
Other important exposures of the Pella beds appear in the 
bluffs of the Des Moines river and along its tributary, Keed 
creek, northwest of Farmington. 
In a section exposed in the northeast bluff of the Des Moines 
river and in the railway cut of the Chicago, Kock Island and 
Pacific Railway two miles north of Farmington (S. W. % Sec. 
23, T. 68 N., R. 8 W.) the Pella is seen to rest directly upon the 
Lower St. Louis. 
SECTION III. 
FEET. INCHES. 
PELLA : 
4. Limestone, compact, gray, brecciated, cap- 
ping brow of bluff 3 4 
3. Concealed. Slope strewn with loose blocks 
of compact gray limestone... 31 
