28o The American Geologist. ^^^'' ^^°^- 
evidently been laid down since the valleys reached ap])roxi- 
mately their ])resent depth., * ''' '"' It is yelloAvish in color, 
tough, jointed, and ol)scurely stratified. Unlike loess it con- 
tains occasional pebbles and ])ockets of sand. A small green- 
stone, two inches long and showing glacial planing on two 
sides, was taken from this silt in the bank of North Branch. 
* * * Above the section described at Braddyville, west of 
the railway track, there is a body of the clay twenty feet thick 
and forming a distinct terrace fifty yards or more in wi.ith 
at the top. The hard enamelled scales of the garpike, Lepi- 
dosteus, were found in this bed at Braddyville, the scales re- 
taining their proper relations to each other as if the fish l»ad 
been buried at the time the silt was forming. '■•' * * The 
same yellow silt is found beneath sandy 'alluvium in the val- 
lev of Buchanan creek, east of Braddyville. It is well shown 
in the bank of the Nishnabotna river west of Essex, where it 
is overlain by six feet of a fine, loess-like silt and two or three 
feet of black loam. At the Rankin Brothers" l)rick yard at 
Shenandoah the section of the clay pit show-s 
3. Loess-like clay 8 ft. 
2. Bluish, stratified clay, clearly an aqueous deposit, but 
flexed more or less as if laid down on an uneven 
N , surface 8 ft. 
I. Porous, dark, granular clay 7 ft. 
"Nos. I and 3 resemble loess, but No. 2 records a distinct 
episode between the more recent and the more ancient period 
of loess formation, during which the valley was temporarily 
flooded." 
"The distribution of this deposit is practically universal in 
all the valleys below a certain level." Prof(^ssor Calvin sug- 
gests two hypotheses for the date and origin of this material — 
one, that it was deposited during the Kansan epoch by the 
melting of the Kansan ice, the other that it resulted in the 
same manner round the margin of the lowan drift, the latter 
being the explanation now generally accepted. I'ao-c county 
is one on the southern boundary of Iowa not faf from the Mis- 
souri river, and almost due north from Lansing. 
Professor J. A. Udden, in describing Pottawattamie cbunty 
(Geol. Iowa, vol. XT, p. 260) situated a little northwest from 
Page countv, Ijut borderiu"- on the Missouri river, savs that 
