In 1937 a portion of U. S. Highway 30 near Belle Plaine, Iowa was re-routed, resulting in extensive cuts through the Nebraskan and Kansan glacial drifts. Several exposures of Aftonian peat were found between the two drifts. The locality at which collections were made is 4.9 miles west of Tama county line on U. S. Highway 30. The peat was prepared for microscopic study and one hundred and fifty plant microfossils were counted. Percentages were computed for each of the levels and the percentages show the abundance of the microfossils at each level. The distribution of the tree-pollens in the study suggests a change from a cold climate at the upper contact to a warmer one at the two and four inch levels, and finally a return to the cold climate. This would seem to correlate with the retreat of the Nebraskan and the invasion of the Kansan ice sheets.
Proceedings of the Iowa Academy of Science
©1940 Iowa Academy of Science, Inc.
Wilson, L. R. and Kosanke, R. M.
"The Microfossils in a Pre-Kansan Peat Deposit near Belle Plaine, Iowa,"
Proceedings of the Iowa Academy of Science, 47(1), 269-269.
Available at: https://scholarworks.uni.edu/pias/vol47/iss1/61