Of all of Iowa's geological formations the Dodge gypsum has held out longest and most resolutely against divulging its age. As is well known, it has been often regarded as Permian, ever since argued by Hall,1 in the middle of the last century; but there were no really direct evidences supporting his notion, and there were no fossils verifying such assumption. Nothing but analogy to other gypsum deposits could ever be adduced. Even Wilder's arguments2 were nothing more than happy analogies; and his conclusions on age and origin could just as well apply to the gypsums of eastern Europe, as to those of Kansas.
Proceedings of the Iowa Academy of Science
©1938 Iowa Academy of Science, Inc.
"Possible Representation of Guadalupan Series of Iowa,"
Proceedings of the Iowa Academy of Science, 45(1), 165-166.
Available at: https://scholarworks.uni.edu/pias/vol45/iss1/34