ammonites
Brachiopods of Rock Grove Mbr., Shell Rock Fm., North-Central Iowa (Devonian of the United States)

Where: Iowa (43.3° N, 92.8° W: paleocoordinates 30.2° S, 37.4° W)

• coordinate based on political unit

• basin-level geographic resolution

When: Rock Grove Member (Shell Rock Formation), Frasnian (383.7 - 376.1 Ma)

• Within Strophodonta cicatricosa zone. Shell Rock as a whole is early-middle Frasnian.

• member-level stratigraphic resolution

Environment/lithology: marine; peloidal, shelly/skeletal, argillaceous limestone and peloidal, shelly/skeletal dolomite

• Witzke et al. (ref. 9582): mainly shallow subtidal.
• From Witzke et al. (PBDB ref. 9582): "..dominated by pelleted to skeletal limestone and dolomite, in part vuggy, and is poorly fossiliferous through much of its lower interval. Crossbedded calcarenites occur locally in the upper beds. The member includes shales and burrowed shaly limestones in the type area. Rock Grove strata incorporate laminated, intraclastic, brecciated, mudcracked, and "birdseye" bearing lithologies, especially in the lower half, to the W and SW..."

Collection methods: Fauna of the Shell Rock not reported here include mollusks, corals, stromatoporoids, and echinoderms. These elements usually dominate the assemblages.

Primary reference: J. Day. 1988. The brachiopod succession of the Late Givetian-Frasnian of Iowa. In N. J. McMillan, A. F. Embry, and D. J. Glass (eds.), Devonian of the World, Volume III. Canadian Society of Petroleum Geologists. Calgary, Alberta, Canada 303-325 [M. Foote/M. Foote/M. Foote] more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 35494: authorized by Michael Foote, entered by Michael Foote on 17.12.2003