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IOWA ACADEMY OF SCIENCE Vor. XXIX, 1922 
conformable relationship with the underlying beds and later in- 
vestigators, in order to account for this situation, have enlisted 
various agents, even faulting in a region so little subject to dias- 
trophism as is Iowa, having been called upon to explain such 
unique phenomena' as may be found in the gypsum area. 
The Iowa Geological Survey has always interested itself in the 
problems presented by the Fort Dodge beds, as the gypsum and 
its associated strata are called, and at three times has carried on 
studies in the region with the hope of reaching a solution of these 
problems. The writer is one of those who has studied this ex- 
tremely interesting region, in connection with the preparation of 
a monographic report by Dr. F. A. Wilder, who was formerly 
connected with the Survey. The results of our field work are 
embodied in certain chapters of this monograph, and our con- 
clusions may be summarized here. 
The gypsum itself is almost everywhere the lowest bed of the 
Fort Dodge stage. In a few places a conglomerate, which evi- 
dently is related to the gypsum rather than to the beds beneath, 
has been found beneath the gypsum, and in some localities a thin 
layer of clay, perhaps residual from decay of the basal layers 
of gypsum, intervenes between the gypsum and the underlying 
shales. The basal conglomerate was described in volume XXV 
of these Proceedings. Overlying the gypsum there is, in most 
places where the beds are exposed, a stratum of red or pink sandy 
Fig. 2. Airplane view of Des Moines valley at Fort Dodge. Soldier Valley is in 
the upper right hand part and is crossed by the viaduct. Lizard Valley is in the 
upper left hand corner. — Courtesy Fort Dodge Chamber of Commerce. 
