During the course of an investigation of the bedrock geology of western Story County, Iowa, our attention was directed to the occurrence of some unusual Pleistocene deposits. These deposits consist of calcareous silts, which from the viewpoint of mineralogy, textural analysis, physiographic expression, and paleontology embrace most of the criteria by which loess is generally described or recognized. These deposits in Story County have been described as loess by Beyer (1898, and 1899). The most apparent but unusual feature of these deposits is their vertical and lateral gradation into till or alluvial material. Similar deposits are now known to occur also in Boone County. Only one of these deposits has been extensively studied, and the purpose of this report is to outline the progress of our investigation and to discuss some of the problems presented by these deposits. Location of area. The silts, described in this report, are known to extend along the course of Onion Creek from the NW 1/4 Sec. 32, upstream through section 29, and into the SE 1/4 section 30, T84N., R24W., Story County, (see figures 1 and 2).
Proceedings of the Iowa Academy of Science
© Copyright 1953 by the Iowa Academy of Science, Inc.
Thomas, L. A.; Riggs, K. A. Jr.; and Tench, R. N.
"Some Loessoid Deposits of Central Iowa,"
Proceedings of the Iowa Academy of Science: Vol. 60:
, Article 54.
Available at: https://scholarworks.uni.edu/pias/vol60/iss1/54