118 
IOWA ACADEMY OF SCIENCE Vor. XXIX, 1922 
wide range in altitudes at which the gypsum is found in Soldier 
valley. At no other place is there known such a variation, but 
actual examination in the field will convince anyone that there 
is no possibility of the existence of faults here. There can not 
be one along the ridge between Soldier and Des Moines valleys, 
for gypsum is present at similar elevations on both flanks of the 
ridge, namely at 1053 feet in the pit of the Fort Dodge Brick and 
Tile Company on the Des Moines valley wall, and at 1046 feet 
in the pit of the Hawkeye Clay Works on the Soldier creek side. 
There can not be a fault across the ridge, for then there would 
be bodies of gypsum at both high and low levels on both sides 
of the fault,- no matter where it was located. And underneath, 
everywhere, unaffected by any faults, except those of the observ- 
ers, are the St. Louis limestones. 
On the west side of the river the Fort Dodge beds have been 
exposed at three places — on the Hawkeye Highway leading west 
from the city, at the pit of the Fort Dodge Clay Works on the 
north bank of Lizard creek and at the south pit across the creek. 
At the two former places the gypsum is high in the walls but 
at the southern locality the contact with the Des Moines beds is 
somewhat lower — it is nearer the deep valley which was cut into 
die old Permian basin. Here again the evidence is in favor of 
normal erosive activity and against any theory of faulting to 
account for the existent conditions. There is no place for faults 
north of the Lizard and neither is there occasion for them on the 
south side when general conditions are taken into account. 
South of Fort Dodge there is a general though irregular rise 
of the gypsum plate toward its margin. The irregularity of the 
floor in this region is shown by the following elevations of the 
gypsum : Vincent clay pit, 1022 feet ; about half a mile up Gypsum 
Hollow, 1040 feet; about a quarter of a mile farther up the Hol- 
low, 1050 feet; at the American gypsum mill 1045 feet. On the 
opposite side of the river the gypsum is 1058 feet above sea level 
where it overlies the conglomerate in the ravine opposite Shady 
Oak and 1055 feet at Johnson Brothers’ clay pit. The Mississip- 
pian strata also show themselves in this locality, namely in the 
river bed and banks opposite Johnson Brothers’ plant, about a mile 
below Shady Oak. 
It would seem then that a simple examination of the phenome- 
na of the gypsum region should convince the fairminded observer 
that there has been no remarkable upheaval or convulsion of na- 
