A slab containing a bony plate from a large armored fish called an arthrodire an early jawed fish that reached 30 feet in
This polished slab of Devonian limestone shows an abundance of fossil stromatoporoid sponges with scattered small corals and other fossils. Stromatoporoids are an extinct group of sponges that possessed hard lime skeletons. Beds rich in stromatoporoid fossils e seen at many places around Coralville Lake, and the slabs seen in these interpretive displays come from layers of the Cedar Valley Group known as the "Idiostroma beds," named after the abundance of small broken branches of a particular type of stromatoporoid. Lumpy and more massive forms of other stromatoporoid sponges are also seen the slabs. In addition, twigs and lumps of the colonial "honeycomb" coral (Favosites) are evident, some encrusted by stromatoporoids.
Caption: The Devonian Diorama at the University of low Museum of Natural History's low Hall on the University
campus, shows the colorful profusion
Topics. This historical marker is listed in these topic lists: Anthropology & Archaeology • Disasters • Environment. A significant historical year for this entry is 1993.
Location. 41° 43.309′ N, 91° 31.933′ W. Marker is near Iowa City, Iowa, in Johnson County. Marker can be reached from Prairie Du Chien Road Northeast. Touch for map. Marker is at or near this postal address: 2850 Prairie Du Chien Rd NE, Iowa City IA 52240, United States of America. Touch for directions.
Other nearby markers. At least 8 other markers are within 4 miles of this marker, measured as the crow flies. Site Geology (here, next to this marker); The Coralville Dam (a few steps from this marker); View from the Overlook Plaza (a few steps from this marker); An Ancient Sea (a few steps from this marker); Samuel Jordan Kirkwood (approx. 3.9 miles away); Old Brick (approx. 4 miles away); Mormon Handcart Brigade Camp (approx. 4.1 miles away); St. Mary's Church (approx. 4.1 miles away). Touch for a list and map of all markers in Iowa City.
Credits. This page was last revised on June 7, 2021. It was originally submitted on June 6, 2021, by Connor Olson of Lemmon, South Dakota. This page has been viewed 102 times since then and 51 times this year. Photos: 1, 2, 3. submitted on June 6, 2021, by Connor Olson of Lemmon, South Dakota. • Mark Hilton was the editor who published this page.