276 
IOWA ACADEMY OF SCIENCES. 
Number 4 is a bed of loose sand, in which the layers of 
finer grained material alternating with those of coarser 
texture indicate a deposit along the bed of a stream in 
which the strength of the current was variable. This sand 
bed contains no trace of calcium carbonate throughout its 
entire thickness. It was probably laid down by the waters 
which resulted from the melting of the Kansan ice. 
Number 3 is a thick bed of clay, which bears numerous 
pebbles and bowlders of various sizes. Many of the lighter 
colored bowlders have partially decayed, and are so rotten 
that they can be broken apart with the hands. For a 
depth of four feet from the top the material has a some- 
what reddish appearance. This color gradually changes 
with the depth through yellow and gray to the bluish color 
of the main body of clay. In the upper portion are several 
pockets and lentils of rather fine-grained sand. The bed 
is cut by numerous joints and cracks into prismatic and 
irregularly shaped blocks and fragments. It is calcareous 
throughout, hydrochloric acid producing vigorous efferves- 
cence at the very top, immediately below the layer of 
sand, as well as in every portion of its depth. 
Number 2 is a layer very different in character from 
that which overlies it, or from that which is found below. 
It is dark brown in color and is largely composed of more 
or less perfectly decayed vegetable matter mixed with a 
soil which contains a considerable amount of sand. Near 
the upper portion of this layer may be found a few frag- 
ments of wood and bits of roots and darker colored patches 
of carbonaceous material. The bed contains no trace of 
calcareous matter. It forms a conspicuous band eighteen 
to twenty-four inches in thickness, which is exposed at 
this horizon for a distance of forty rods. 
Number 1 is a bed of drift which resembles in many 
respects Number 3 above. Many of the pebbles and 
bowlders which it carries are beautifully polished and stri- 
ated. In the lower portion it is bluish gray in color, but 
to a depth of three or four feet from the top the clay 
has a slightly reddish tinge. This red color, however, is 
not so marked as in the oxidized surface materials of the 
