46 
ON THE GEOLOGY AND NATURAL HISTORY 
Feet. 
14. Two or three layers of soft fine-grained sandstone, more or less argillaceous, and separated by seams of 
day,. 2 
15. Bluish and ash-colored clays, . . . . . . . . . . . • • .21 
16. Alternate layers of hard bluish gray limestone, and seams of clay with sandy concretions, ... 3 
17. Rather hard yellowish limestone, with Fusulina, .......... 24 
18. Ash-colored clay, not very well exposed, ............ 15 
19. Yellowish impure limestone, with Fusulina, ........... 2 
20. Ash-colored laminated clays—above the creek, ........... 5 
About three hundred yards below where this section was taken, the creek was observed 
to fall nearly a foot, over a ledge of hard limestone ; and one mile further down, the bed of 
the creek is composed of a hard yellow limestone, containing great numbers of Fusulina . 
At these localities Mill creek is probably not elevated more than thirty feet above the 
Kansas. 
Near half a mile east or southeast of the point where the Fusulinai limestone was seen 
in the bed of Mill creek, and at a somewhat higher elevation, we saw apparently the same 
bed of Fusulina limestone, showing a thickness of three feet. Under this there was at one 
place exposed a thickness of some four or five feet of very fine yellow sandstone with 
minute specks of mica. These exposures indicate a moderate dip of the strata towards 
the west or northwest. 
On the north side of the Kansas, in a direction a little west of north, and about sixteen 
miles from the last-mentioned localities, we observed an outcrop, on a small stream marked 
“ Last creek” on the maps, presenting the following section, descending: 
Feet. 
J. Seams of yellow magnesian limestone, alternating with clay, showing a thickness of about, ... 8 
2. Yellow soft granular magnesian limestone, containing Productus Norwoodi, and an undetermined species 
of Myalina, ................. 4 
3. Fine laminated black shale, .............. 1 
4. Gray rather soft argillaceous limestone, ............ 1 
5. Blue somewhat indurated very fine calcareous clay, containing at its junction with the next bed below CJto- 
netes, Synocladia biserial is, Chcetetes, and fragments of Crinoids, ....... 9 
6. Seams of hard compact gray limestone, alternating with softer argillo-calcareous matter, and containing casts 
of many small Cypr icardia-Wke shells, small Murcliisonia, Pleurotomaria, Macrocliei/us, Naticopsis, Bel- 
lerophon, &c., ................ 2 
7. Bluish laminated clays weathering to drab color, ........... 4 
8. Yellow rather soft granular magnesian limestone, with embedded fragments of harder more compact do., . 54 
9. Bluish indurated calcareous clays, ... .......... 3 
The base of this section is evidently not elevated much above the Kansas, as it extends 
down to the bottom of a deep ravine formed by the creek, while its top appeared to be 
