STROMATOLITES
DESCRIPTION: Stromatolites are layered mound-like structures formed by the trapping of sediment by sheets of cyanobacteria.
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Figure 1 - Differential weathering exposes stromatolitic mounds that existed near the shoreline of the Lower Ordovician sea in Central Texas. Honeycut Bend, TX.
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Figure 2 - Stromatolites of the Siyeh Formation near Logan Pass, Glacier NP.
INVERTEBRATE FOSSILS
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Figure 1 - Colonial Coral (Syringopora?) from Monroe Canyon Limestone of Little Flay Canyon, IDAHO. (Photo 1982)
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Figure 2 - Solitary Rugose Corals. Monroe Canyon Limestone in Little Flat Canyon, Utah. (Photo 1982)
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Figure 3 - Crinoid Columnals and segments. The larger five-sided particles (columnals) make up the stem of crinoids. Other smaller particles are likely parts of the crinoid calyx. Wyoming Rockies. Probably Mississippian in age. (Photo 1983)
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Figure 4 - Molluscan Packstone. Cross-sections are of bivalves that have been replaced by silica and have differentially eroded from a limestone matrix. Triassic Thaynes Formation. Montpelier Canyon, ID. (Photo 1983)
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Figure 5 - Ordovician Brachiopods. Southern Appalachians.
TRACE FOSSILS
DESCRIPTION - Trace Fossils, also called Ichnofossils, are evidence of biological activity in the fossil record that don't include the actual parts of the animal or plant. These can include footprints, burrows, and trails.
SELECTED REFERENCES:
-Marintsch, Edward and Robert Finks. 1982. Lower Devonian Ichnofacies at Highland Mills, NY and their gradual displacement across environmental gradients. J. Paleontol., 56: pp. 1050-1078.
-Marintsch, Edward nad Robert Finks, .1978. Zoophycos size may indicate environmental gradients. Lethaia, 11: p. 273-279.
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Figure 1 - In the Swan River Quartzite (Ordovician) outside of Logan, Utah. These markings appear to be tubes made by burrowing that have been subsequently filled by coarser sediment from stratigraphically above.
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Figure 2 - Scalarituba. Black clay forms lining of tubes. Pine Hill Fm., Devonian, NY.
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Figure 3 - Zoophycos. Part of the Zoophycos web on bedding plane indicative of intensive reworking of sediment for food. Esopus Fm., Devonian, NY.
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Figure 4 - Zoophycos. Part of the Zoophycos web on the bedding surface.Esopus Fm., Devonian, NY.
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Figure 5 - Zoophycos. Esopus Fm., Devonian, NY. Side view of bed showing meniscus structures as entire bed is reworked for food.
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Figure 6 - Chondrites. Black clay forms lining of branching tubes. Esopus Fm., Devonian, NY.
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Figure 7 - Phycodes. Multiple tubular burrows emerge from a single tube. Esopus Fm., Devonian, NY.
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Figure 8 - Planolites.Burrows parallel to bedding surface. Esopus Fm., Devonian, NY.
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Figure 9 - Skolithos and Monocraterion. Near surface vertical tubes. Esopus Fm., Devonian, NY.
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Figure 10 - Skolithos and Monocraterion. Near surface vertical tubes. Esopus Fm., Devonian, NY.