Recent diastatic analyses of our Des Moines coal measures, particularly of the great Arkansan centrum, or delta, of which the Iowa coal measures are a part, after the paradigm of the Cordilleran Cretacic geosyncline, indicate that only a relatively small proportion of the original deposition of coal-bearing beds now remain to us. Present thickness of the Iowa coal measures is perhaps 300 to 400 feet. In the beginning, the volume appears to have been more than four miles thick. The vast missing bulk was removed through erosion, mainly regional planation before the great Missourian series of limestones was laid down.
Proceedings of the Iowa Academy of Science
©1937 Iowa Academy of Science, Inc.
Keyes, Charles R.
"Original Great Magnitude of Our Coal Measures,"
Proceedings of the Iowa Academy of Science, 44(1), 132-133.
Available at: https://scholarworks.uni.edu/pias/vol44/iss1/34