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http://capp.water.usgs.gov/gwa/ch_j/J-text7.html

http://capp.water.usgs.gov/gwa/ch_j/J-text7.html. http://files.dnr.state.mn.us/waters/groundwater_section/mapping/cga/c14_wabasha/pdf_files/C-14_Plate08.pdf. CAMBRIAN SYSTEM in Minnesota Upper Cambrian – St. Croixian. Cross-bedded sandstones.

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http://capp.water.usgs.gov/gwa/ch_j/J-text7.html

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  1. http://capp.water.usgs.gov/gwa/ch_j/J-text7.html

  2. http://files.dnr.state.mn.us/waters/groundwater_section/mapping/cga/c14_wabasha/pdf_files/C-14_Plate08.pdfhttp://files.dnr.state.mn.us/waters/groundwater_section/mapping/cga/c14_wabasha/pdf_files/C-14_Plate08.pdf

  3. CAMBRIAN SYSTEM in Minnesota Upper Cambrian – St. Croixian Cross-bedded sandstones In Minnesota and Wisconsin unconformable on PreCambrian strata

  4. Climactichnites

  5. Climactichnites

  6. Climactichnites

  7. Spectacular trace fossils (Ichnofossils) Climactichnites resemble tracks made by a motorcycle both is size and character. Described by Sir William Logan in1860, Climactichnites was believed at that time to come from the oldest sedimentary formation known; the Canadian formation is now known to be Upper Cambrian. The fossil caused considerable controversy among paleontologists, and speculation regarding the track maker's identity abounded. Arthropods with soft bodies were denied by the lack of footprints. The possibility of a snail was denied by the V-shaped ridges, and that no known Cambrian snail or worm (even today) can account for the tracks that can be six or more inches wide.

  8. More recently, Getty and Hagadorn, have suggested that Climactichnites fossils are body impressions of a slug-like creature that crawled across the surface – preservation dependent on a biofilm of alga on the sand flats. Getty, P. R.; Hagadorn, J. W. (2008). "Reinterpretation of Climactichnites Logan 1860 to Include Subsurface Burrows, and Erection of Musculopodus for Resting Traces of the Trailmaker". Journal of Paleontology82 (6): 1161–1172. doi:10.1666/08-004.1

  9. Scyphozoans Jellyfish medusae

  10. The Cambrian was of great evolutionary innovation, with many major groups of organisms appearing within a span of about forty million years. Trace fossils made by animals also show increased diversity in Cambrian rocks, showing that the animals of the Cambrian were developing new ecological niches and strategies -- such as active hunting, burrowing deeply into sediment, and making complex branching burrows. Almost every metazoan phylum with hard parts, and many that lack hard parts, made their first appearance in the Cambrian. Although almost all of the living marine phyla were present, most were represented by classes that have since gone extinct or faded in importance. The Brachiopoda for example, were represented by the relatively primitive inarticulate brachiopods.

  11. Other Cambrian invertebrates with mineralized skeletons included: • Trilobites, archeocyathids, inarticulate brachiopods, monoplacophorans, echinoderms. • Cambrian echinoderms were predominantly unfamiliar and strange-looking types such as early edrioasteroids, eocrinoids, and helicoplacoids. Starfish and sea urchins had not yet evolved. • In addition there were problematic conical fossils known as hyolithids.

  12. Trilobites General morphology skeletal parts (from the Treatise of Invertebrate Paleo) Olenellus Mostly members of the benthos Bottom-dwellers Plate of Upper Cambrian fossils from Mt. Jubillee, Columbia River Valley, British Columbia, described by Teiichi Kobayashi,1938

  13. Upper Cambrian trilobites and lingulids from Wisconsin

  14. Inarticulate Brachiopods ‘living fossils’ Subphylum Linguliformea (L. Camb. - Rec.) chitonophosphatic shells Fossil Spatula-shaped shell with fleshy pedical projecting from between The two valves In burrow, organism retractile on a pedicle Inarticulate brachiopods lack interlocking hinge mechanisms and have the valves held together only by muscles. Modern forms e.g. Lingula, burrow in soft, muddy, dark-colored sediments and move up and down within their burrows on a long leathery or fleshy stalk-like extension (pedical). They are found in marine or brackish water in poorly -oxygenated estuaries and mud flats.

  15. Monoplacophorans – primitive molluscs Possess segmented muscles and organs ancestral to later mollusc classes Prior to 1952, the monoplacophorans were known only from fossil shells from the Cambrian and Devonian. Then in that year the 'Galathea' expedition dredged up 10 living specimens of Neopilina galathea. These two species are the only known living representatives of this class

  16. Phylum uncertainClass HYOLITHA Marek, 1963Family HYOLITHIDAE Nicholson, 1872Genus Hyolithes Eichwald, 1840 Reconstruction of the hyolithid animal Fossils of Hyolithes

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