295 The Geological Society of America Field Guide 10 2008 Plants, fish, turtles, and insects from the Morrison Formation: A Late Jurassic ecosystem near Cañon City, Colorado Mark A. Gorman II* Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309-0399, USA Ian M. Miller Denver Museum of Nature & Science, 2001 Colorado Blvd., Denver, Colorado 80205, USA Jason D. Pardo Department of Biological Sciences, University of Colorado, Boulder, Colorado 80309-0334, USA Bryan J. Small Denver Museum of Nature & Science, 2001 Colorado Blvd., Denver, Colorado 80205, USA ABSTRACT The Morrison Formation is a laterally extensive terrestrial deposit representing an ecologically diverse assemblage of paleoenvironments from the Late Jurassic of western North America. Although the Morrison Formation has recently been inter- preted as a semiarid lowland savannah on the basis of geological and paleobiological indicators, many microenvironments within this system are more consistent with new interpretations of the Morrison as a ground-water dominated “wetland” deposit. Here we report new fossils from a little-studied exposure of the Morrison Formation in and around Temple Canyon Park near Cañon City, Colorado. The Temple Canyon section shows a relatively thin sequence of conglomerate, sandstone, siltstone, mudstone, and limestone beds representing alluvial to fluvial and possibly lacustrine deposition. The section rests on Precambrian basement and is unconformably overlain by the Lower Cretaceous Lytle Formation. The mudstone and limestone beds preserve an abundant fossil flora and fauna distinct from those previously described from the Morrison Formation. The floral assemblage includes species of algae, bryophytes, ferns, gink- gophytes, horsetails, cycads, bennettites, and conifers; together these plants indicate a warm climate with abundant local water supply. The faunal assemblage contains ostracodes, conchostracans, traces of aquatic insect larvae, a terrestrial insect body fossil, prosobranch and pulmonate gastropods, many species of fish, a possible frog, and rare turtle remains. The presence of prosobranch gastropods, fish, and aquatic insect larvae suggests a perennial water body with high oxygen content, while the presence of conchostracans and pulmonate gastropods may indicate some fluctuation in water quality. Keywords: Morrison Formation, Jurassic, Cañon City, Colorado, paleoecology. *Mark.Gorman@colorado.edu Gorman, M.A., II, Miller, I.M., Pardo, J.D., and Small, B.J., 2008, Plants, fish, turtles, and insects from the Morrison Formation: A Late Jurassic ecosystem near Cañon City, Colorado, in Raynolds, R.G., ed., Roaming the Rocky Mountains and Environs: Geological Field Trips: Geological Society of America Field Guide 10, p. 295–310, doi: 10.1130/2008.fld010(15). For permission to copy, contact editing@geosociety.org. ©2008 The Geological Society of America. All rights reserved.