Abstract

A collection of crinoids and other fossils from Crawfordsville, Indiana, in the University of California at Berkeley paleontology collection is discussed from a paleoecologic point of view. A brief history of the fossil site and stratigraphy is given. The crinoids are judged to have been part of a large colony that was dominated by echinoderms and was typically epifaunal in nature. The epifauna was stratified, with 2 levels of crinoids above the sea floor, and a sea bottom group of corals, brachiopods, bryozoans, and sponges. The 2 levels of crinoids are differentiated not only on length of stem, but also on relative height of crown, width of stem, and prominence of the dorsal cup. Relative densities of invertebrates in the collection in terms of total prepared surface area are given and a hypothetical reconstruction of 1 sq m of sea floor and cross-section of the epifauna is given. A previous hypothesis that the crinoids were rafted to their site of deposition is rejected.

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