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105 
IOWA ACADEMY OF SCIENCES. 
relief on the face of the bluff where exposed to the in- 
fluences of weathering. See plate X. 
Among the plants whose remains were found in these 
upper vegetable layers there occur the stems and leaves 
and rhizoids of species of mosses which Prof. J. M. Hol- 
zinger has identified with Rypnum ( CamptothecAurn ) nitens 
(Schreb.) Schimp, and Htjpmim {Ilarpidium,) flu items Linn. 
Both of the above mosses are aquatic species. The former 
lives at present only in peat bogs and prairie swamps of 
more northern lands. The latter has a wider distribution. 
It inhabits ponds and marshes in both northern and tem- 
perate latitudes. With these mosses were also found the 
rootstock of a small species of fern, blades of some strap- 
shaped, grass-like leaves, and a fragment of a leaf resem- 
bling that of a species of populus. Numerous leaves and 
twigs of some cone bearing trees also occur. The leaves 
on these branchlets are sessile. They are jointed to short 
sterigmata or pedestals, and are arranged along the twig 
in a manner similar to those of species of Picea or Spruce. 
Disconnected limbs and wing-covers of beetles are occa- 
sionally encountered. 
The layers of organic matter are thicker near to, and 
above, the middle of the member. Many of the sand lay- 
ers show very thin, brown laminae of peaty substance 
which indicate that even the deposition of the sand mate- 
rial took place very slowly. 
This peat bearing member is exposed in the face of a 
bluff for a distance of about one hundred feet. Near the 
west end of the exposure a small ravine has been cut back 
into the hill for a distance of half a dozen rods. The vege- 
table horizon appears in the bank on either side of this 
ravine, and it is overlain with a thickness of more than 
twenty feet of yellow colored till. 
Number 3 of the section represents a bed of Kansan drift 
whose lime constituent is leached from its superficial por- 
tion, and whose iron content is oxidized to a greater or less 
degree throughout its entire depth. There is nothing 
peculiar in the color or in the contents of this till as here 
exposed. 
