During the summer of 1953, an outcrop of ferruginous pebble conglomerate was found in central Jones county, Iowa. This outcrop is located about three miles north of the town of Olin, along the eastern edge of Iowa Highway 38 between Olin and the junction of Highways 38 and 64. It is near the center of the SE¼ of section 25, T. 84 N., R. 3W. (Jackson Township) Jones County. Topographically, it occurs about midway up the gentle north side of the valley of the Wapsipinicon River. The rock at this locality extends horizontally for about thirty feet and has about five feet of its thickness exposed. Along the tops of the exposed bedding planes, weathering has produced a mottled black-gray color. On fresh surfaces and on some of the vertical fractures, the rock is light-gray, pale yellow-brown, or dull-red in color.
Proceedings of the Iowa Academy of Science
©1955 Iowa Academy of Science, Inc.
Tuttle, Sherwood D. and Northup, Richard C.
"A New Outcrop of the Rockville Conglomerate,"
Proceedings of the Iowa Academy of Science, 62(1), 366-372.
Available at: https://scholarworks.uni.edu/pias/vol62/iss1/39