Stoux City Academy of Science and Letters. 157 
sils found in these beds were pronounced by Professor E. 
D. Cope to be “three left superior molars of the horse, 
Equus major Dek., of Pleistocene age,—entirely restrict- 
ed to that horizon.” The megalonyx remains found in 
Mills County while not restricted to the Pleistocene (they 
may also be Pliocene) are somewhat characteristic of 
that formation so that although it is not known that the 
beds in Mills County and Woodbury County are con- 
nected, paleontologic evidence does not strongly indicate 
the Tertiary age of these particular deposits. 
In the work of the writer in Dakota County no evi- 
dence could be found for the presence of Tertiary depos- 
its. However, artificial sections are not so numerous as 
in Woodbury County, lowa, and it is possible that sand 
pits may be opened in the future in beds bearing the same 
relation to the drift as those at Riverside. Professor 
Todd has based some of his evidence as to the distribu- 
tion of the sands in question on drill records. The writer 
hesitates to rely upon such records, especially in discrim- 
inating between classes of deposits so closely related 
both in character and position. In personally supervis- 
ing the drilling of a tubular well in Dakota County a pre- 
Glacial valley was discovered, which proved to have sev- 
eral alterations of sands, gravels, and clays below the 
loess. All of the gravel was water worn and some of it 
showed distinct evidence of ice action. The sand was 
fine, white, and compact, characteristic of a stream de- 
posit. 
In the absence of evidence of Tertiary deposits there 
is added evidence of an elevated land area over what is 
now the middle Missouri Valley and to the eastward, fol- 
lowing the orographic movements at the close of the Cre- 
taceous. Subsequent to this and prior to Glacial condi- 
tions there may have been a slight subsidence during 
which this region was covered by a shallow lake in which 
the doubtful sands and gravels were deposited as shore 
and estuary materials, followed by an elevated condition 
of stream cutting in which the greater part of these de- 
posits were removed by erosion. The height to which 
the land was raised was doubtless considerably greater 
than its present elevation. In the interval between this 
upward movement and the advent of the ice Missouri 
River began to cut its present trough. The depth eventu- 
ally reached was at least 100 feet below the present 
