Opening a quarry on the southern edge of a Middle River bluff, the quarryman exposed 20 feet of the top layer of limestone. The top face of the limestone was covered with glacial scratches, hundreds of them running parallel north and south. The scratches marked the direction of floor of the ice. The valley of Middle River here is deep, and its course is east and west. A number of large boulders, house size, on the uplands on the south side of the river show that the valley must have been filled with ice when the boulders crossed the river and valley.
Proceedings of the Iowa Academy of Science
©1940 Iowa Academy of Science, Inc.
Proceedings of the Iowa Academy of Science, 47(1), 271-272.
Available at: https://scholarworks.uni.edu/pias/vol47/iss1/65