Wikipedia

Beecher's Trilobite Bed

Beecher's Trilobite Bed is a Konservat-Lagerstätte of Late Ordovician (Caradoc) age located within the Frankfort Shale in Cleveland's Glen, Oneida County, New York, USA.[1][2] Only 3–4 centimeters thick, Beecher's Trilobite Bed has yielded numerous exceptionally preserved trilobites with the ventral anatomy and soft tissue intact, the soft tissue preserved by pyrite replacement.[2][3] Pyritisation allows the use of X-rays to study fine detail of preserved soft body parts still within the host rock.[4][5] Pyrite replacement of soft tissue is unusual in the fossil record;[6] the only Lagerstätten thought to show such preservation were Beecher's Trilobite Bed, the Devonian Hunsrück Slates of Germany, and the Jurassic beds of La Voulte-sur-Rhône in France,[7] although new locations are coming to light in New York state.[8]

Beecher's Trilobite Bed
Stratigraphic range: Late Ordovician (Caradoc)
445 Ma
↓
Two specimens of the trilobite species Triarthrus eatoni. These trilobites are preserved with pyrite, allowing for the presence of soft body parts.
TypeBed
Unit ofFrankfort Formation
AreaSmall quarry only
Thickness3–4 cm (1.2–1.6 in)
Lithology
PrimaryShale
Location
Coordinates43°15.2′N 75°24.5′W / 43.2533°N 75.4083°W / 43.2533; -75.4083
RegionOneida Co., New York
Country United States
ExtentVery limited
Type section
Named forCharles Emerson Beecher

History of research edit

Originally discovered in 1892 by William S. Valiant, the site was thoroughly excavated from 1893 to 1895 by Charles Emerson Beecher (after whom the location is named) of Yale University, after which time the location was thought to be exhausted of fossils and excavations ceased.[9] Beecher published three papers describing a trilobite larval form,[10] trilobite limbs[11] and trilobite ventral anatomy[12] from material collected from the site he established. Beecher died unexpectedly in 1904; much material, as well as details of the location, was lost.[13] Research was subsequently limited to study of material collected during the original excavations that had been distributed to various institutions.[13][14][15]

Amateur fossil collectors Tom E. Whiteley (also responsible for rediscovering the Walcott-Rust quarry) and Dan Cooper rediscovered the location in 1984[16] and from 1985 academic excavations and studies (re)-commenced.[17] At least 4 other fossil bearing horizons exhibiting similar preservation have subsequently been found at the original site.[17] The small quarry at the site is currently closed to public access,[18] being on private land[17] and administered by Yale Peabody Museum as part of ongoing research projects.[19]

Sedimentology, environment of deposition and preservation edit

Further information: Beecher's Trilobite type preservation

The original Beecher's Trilobite Bed is found within a thick succession of fine grained turbidite beds, the fossiliferous bed is about 40 mm thick lying on a scoured mudstone surface with remnants of burrows.[14] Well preserved fossil remains are found 7–10 mm above the base parallel to the bedding plane, strongly aligned by the current, with as many facing up as down.[6][12][14] Chemically, the bed contains high iron coupled with low organic carbon and low organic sulfur.[6]

Fauna edit

The trilobite Triarthrus eatoni comprises 85% of the organisms sampled at the locality, other taxa include graptolites, branching algae, brachiopods and problematica (incertae sedis).[20] The trilobites Cryptolithus bellulus (Ulrich), Cornuproetus beecheri (Ruedeman), Primaspis crosotus (Locke) are also recorded.[2]

See also edit

References edit

  1. ^ Martha Buck's senior thesis on the Beecher's Trilobite Bed Archived 2008-07-06 at the Wayback Machine
  2. ^ a b c Photos (and more) of trilobites from Beecher's Trilobite Bed from Yale Peabody Museum Archived 2008-10-07 at the Wayback Machine
  3. ^ Butterfield, Nicholas J. (2003). "Exceptional Fossil Preservation and the Cambrian Explosion". Integrative and Comparative Biology. 43 (1): 166–177. doi:10.1093/icb/43.1.166. PMID 21680421.
  4. ^ Simon Conway Morris (1991). "In search of the lost fossil record" (PDF). Endeavour. New Series. 15 (4): 158–164. doi:10.1016/0160-9327(91)90121-Q.[permanent dead link]
  5. ^ X-ray images and 3D GIFs of preserved trilobite appendages by Amherst College Archived 2008-07-06 at the Wayback Machine
  6. ^ a b c Derek E.G. Briggs; Simon H. Bottrell; Robert Raiswell (1991). "Pyritization of soft-bodied fossils: Beecher's Trilobite Bed, Upper Ordovician, New York State". Geology. 19 (12): 1221–1224. Bibcode:1991Geo....19.1221B. doi:10.1130/0091-7613(1991)019<1221:POSBFB>2.3.CO;2.
  7. ^ Paul A. Selden; John R. Nudds (2005). Evolution of Fossil Ecosystems (PDF). University of Chicago Press, IL. p. 192. ISBN 978-0-226-74641-8. Archived from the original (PDF) on 2011-07-14. see page 41
  8. ^ Farrell, Úna C.; Briggs, Derek E. G. (2008). "Pyritized olenid trilobite faunas of upstate NY: palaeoecology and taphonomy (abstract)" (PDF). Palaeontological Association Programme with Abstracts. 52: 23. Archived from the original (PDF) on 2010-02-15.
  9. ^ Etter, Walter (2002). "Beecher's Trilobite Bed: Ordovician Pyritization for the Other Half of the Trilobite". In David J. Bottjer; Walter Etter; James W. Hagadorn; Carol M. Tang (eds.). Exceptional Fossil Preservation: A Unique View on the Evolution of Marine Life. Columbia University Press, NY. pp. 131–142.
  10. ^ Beecher, C.E. (1893a). "A larval form of Triarthrus". American Journal of Science. 46 (275): 361–362. Bibcode:1893AmJS...46..378B. doi:10.2475/ajs.s3-46.275.378. S2CID 131502904.
  11. ^ Beecher, C.E. (1893b). "On the thoracic legs of Triarthrus". American Journal of Science. 46 (276): 467–470. doi:10.2475/ajs.s3-46.276.467. S2CID 130872645.
  12. ^ a b Beecher, C.E. (1902). "The ventral integument of trilobites". American Journal of Science. Series 4. 13 (75): 165–173. Bibcode:1902AmJS...13..165B. doi:10.2475/ajs.s4-13.75.165.
  13. ^ a b Raymond, Percy E. (1920). "The Appendages, Anatomy and Relationships of Trilobites". The Memoirs of the Connecticut Academy of Arts and Sciences. 7.
  14. ^ a b c Cisne, John L. (1973). "Beecher's Trilobite Bed revisited; ecology of an Ordovician deepwater fauna". Postilla. 160: 1–25.
  15. ^ Cisne, John L. (1981). "Triarthrus Eatoni (Trilobita): Anatomy of its exoskeletal, skeletomuscular, and digestive systems". Palaeontographica Americana. 9: 1–142.
  16. ^ Brett, Carlton E.; Whiteley, Thomas E. (2005). "Presentation of the Harrell L. Strimple Award of the Paleontological Society to Thomas E. Whitely/response by Thomeas E. Whitely". Journal of Paleontology. 79 (4): 831–4. doi:10.1666/0022-3360(2005)079[0831:POTHLS]2.0.CO;2. S2CID 130851276.
  17. ^ a b c Farrell, Una (2008). "Revisiting Beecher's Trilobite Beds" (PDF). Yale Environmental News. 13 (1): 9.
  18. ^ Forum talk regarding quarry access. Archived 2011-06-07 at the Wayback Machine
  19. ^ Yale Peabody (Briggs Laboratory) research projects. Archived 2008-04-25 at the Wayback Machine
  20. ^ James W. Hagadorn; Martha M. Buck (2004). "Digital Paleobiology and Taphonomy of an Ordovician lagerstätte: Beecher's Trilobite Bed". Geological Society of America Abstracts with Programs. 36 (5): 383.

External links edit


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