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Sketch by Richter (1926) showing spreite in a Diplocraterion parallelum burrow.. Diplocraterion is an ichnogenus describing vertical U-shaped burrows having a spreite (weblike construction) between the two limbs of the U. [1] [2] The spreite of an individual Diplocraterion trace can be either protrusive (between the paired tubes) or retrusive (below the paired tubes). [3]
Index fossils must have a short vertical range, wide geographic distribution and rapid evolutionary trends. Another term, "zone fossil", is used when the fossil has all the characters stated above except wide geographical distribution; thus, they correlate the surrounding rock to a biozone rather than a specific time period.
However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to help identify biozones, as they make up the basic biostratigraphy units, and define geological time periods based upon the fossil species found within each section.
This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there.
The trackway Protichnites from the Cambrian, Blackberry Hill, central Wisconsin. A trace fossil, also known as an ichnofossil (/ ˈ ɪ k n oʊ f ɒ s ɪ l /; from Greek: ἴχνος ikhnos "trace, track"), is a fossil record of biological activity by lifeforms but not the preserved remains of the organism itself. [1]
Fossil collecting (sometimes, in a non-scientific sense, fossil hunting) is the collection of the fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many still collect fossils and study fossils as amateurs.
Knightia is an extinct genus of clupeid bony fish that lived in the freshwater lakes and rivers of North America and Asia during the Eocene epoch.The genus was erected by David Starr Jordan in 1907, in honor of the late University of Wyoming professor Wilbur Clinton Knight, "an indefatigable student of the paleontology of the Rocky Mountains."