TWENTY-EIGHTH ANNUAL MEETING. eT. 
- having been measured. No. 1, from the edge of the marsh, represents the most 
ancient period; No. 3, from the middle of the marsh, the most recent. 
To sum up: First, all Michigan lakes are disappearing, not by drainage or 
evaporation altogether, but by being converted into bogs or marshes. Many shal- 
low lakes are already closed in that manner; all others are closing. Second, de- 
posits in those lakes do not succeed each other from the bottom upward, but from 
the sides centerward. A find resting on the clay four feet below the surface near 
the edge of a marsh or ancient lake may represent a time vastly anterior to a find 
similarly situated 20 feet below the surface near the center of the same marsh. 
Another closing observation: Additions of growth in a marsh are not made 
entirely by horizontal deposits of foliage, but largely by perpendicular additions 
of grass roots throughout the extent of the newly forming marsh and by perpen- 
dicular additions of grass leaves overhanging the edge next the lake. Pressure is 
mostly horizontal and from the center of the lake toward its periphery by the 
swelling of the ice in the lake in winter. This aids in making the material con- 
stantly more compact after being once formed. It aids also in thickening the de- 
posit by reducing the surface dimensions. 
THE STRATIGRAPHY OF SHAWNEE COUNTY. 
By J. W. BEEDE, Topeka, Kan. Read before the Academy January 4, 1896. 
There are good exposures of the Upper Coal Measures, and especially of the 
highest Carboniferous coal-beds of workable thickness in the state, in Shawnee 
county. The best-sections are the bluffs on the south side of the Kansas river. 
The first students of this section of Kansas geology were Meek and Hayden in 
1858, and Prof. G. C. Swallow in 1865. Prof. O. St. John published the results 
of his work in 1881 and 1882. Later Prof. Charles S. Prosser and Prof. E. Ha- 
worth contributed to the knowledge of the region. 
GENERAL DESCRIPTION. 
There are about 550 feet of the Upper Coal Measures strata exposed, ranging 
from about 1,875 to 2,425 feet above the base of the Coal Measures.* The strata 
are a succession of limestones, shales, and coal. - They dip to the west about 10 
feet to the mile. There are no faults or folds of any consequence. The highest 
stratum of coal found in paying quantity in the eastern half of the state traverses 
the county in a northerly direction, passing through the central part. 
The topography is comparatively simple. The Kansas river crosses the county 
from west to east, with a broad valley situated largely on the north side of the 
river. North of the river bottom is a rolling prairie, which rises to an elevation 
of about 1,100 feet A. T. at the north line of the county. A prairie extends from 
the south bluff of the river to a high divide, which traverses the county a little 
south of west, being intercepted for a few miles near Pauline. This divide 
reaches its highest point in the southwest corner of the county, where it is 1,200 
feet A.T.+ In the southern part of the county lies the broad valley of Waka- 
rusa creek, which is nearly as low as the river bottom itself. Three heavy lime- 
stone systems give the more rugged topography to the county. 
While we do not enter into the discussion of the subject in this paper, it may 
*See Prof. E. Haworth, Kan. Univ. Quar., Vol. 11, No. 4, April, 1895. 
7 U.S. topographic sheets. 
