In the Loomis quarry, located in the NW1/4 sec. 29 T. 91N., R. 13W., Bremer County, Iowa, there is an unusual exposure of an unconformity between the Silurian and the Devonian sediments. Several Niagaran hummocks rise approximately 30 feet above the general Silurian level with Devonian sediments (Cedar Valley and Wapsipinicon) deposited against the Hanks of the Niagaran remnants. A basal Wapsipinicon breccia is exposed in this section. Chert from the Silurian forms an important part of the breccia.
Proceedings of the Iowa Academy of Science
©1962 Iowa Academy of Science, Inc.
Dorheim, Fred H. and Kock, Don L.
"Unusual Exposure of Silurian-Devonian Unconformity in Loomis Quarry Near Denver, lowa,"
Proceedings of the Iowa Academy of Science, 69(1), 341-350.
Available at: https://scholarworks.uni.edu/pias/vol69/iss1/55