Lansing Pleistocene (jeology. — IVinehell. 271 
deeper still at least twenty-four feet below the surface of the 
creek's flood-plain — in all, a known excavation in the Carbon- 
iferous limestones and shales a perpendicular gorge one hun- 
dred and eleven feet deep, with a probability of fifty feet still 
deeper at the creek's mouth, and at least fifty feet of strata 
lying above the quarries on the north side. In other words, 
this little "periodic run-off" develops, on being examined, into 
a constant stream occupying an ancient gorge that dates prob- 
ably from pre-glacial time. 
Whether the present channel is "aggrading" at the present 
time, while the bottom land of the ^Missouri adjacent is in a 
degradational stage (No. 5) is beyond the scope of the writer's 
immediate apprehension. He can only state that it would be 
a condition of contrariety at the point of junction of two 
streams which appears singular, if not inconceivable, and es- 
pecially in the light of the perfect adjustment which is affirmed 
(in No. 2) as a concomitant condition. 
5. AVhether the bottom land of the Missouri at the Con- 
cannon farm is at present being lowered as the resultant effect 
of scour-and-fill, or is being raised, the writer has no positive 
data by which to form any opinion. That the Missouri river 
once flowed past the site of the Concannon farm with its sur- 
face from fifty to seventy-five feet lower than at present, as 
all along its course in its pre-glacial gorge, there is abundant 
evidence to show. That this deep rock-cut gorge was afret' 
by the recurring- glacial epochs cannot be questioned, and that 
it was filled to its brim, and sometimes beyond, by the lowan 
epoch is demonstrable. That this filling was by water at cer- 
tain latitudes, by silty w-ater at others and by silt, called valley 
loess, at ethers is perhaps equally demonstrable That this start- 
ified valley loess, at still higher latitudes, grades insensibly into 
the upland loess, losing gradually its preference for the immed- 
iate valley, and pari passu its water-laid structure and assort- 
ment and that this loess has been re-excavated by the stream, is 
in the opinion of the writer as evident as any geologic principle 
of Pleistocene time. That this re-excavation- was interrupted 
by the waters resulting from the Wisconsin epoch of glacia- 
tion, and the action was reversed, so that a refilling began, is 
proved by the Wisconsin terraces that now rise higher than 
the river level. That the Wisconsin terraces toward the north 
