Ordovician Period
Ordovician period

Notes & References

Paleozoic Era
   Cambrian Period
   Ordovician Period    
      Early Ordovician Epoch
      Middle Ordovician Epoch
      Late Ordovician Epoch
   Silurian Period
   Devonian Period
   Carboniferous Period
   Permian Period



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Bergström SM & GL Albanesi (2001),Validity of the species name Tripodus laevis Bradshaw 1969. We do not know the exact provenance of this short article.

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[1]  The "top five" are, more or less in order, the end-Permian, the Ordovician Ice Age, the KT, the Frasnian-Famennian events, and the end-Jurassic. In our opinion, the last two scarcely count. The Frasnian-Famennian extinctions actually began in the Middle Devonian and were too diffuse to be treated as a single event. The end-Jurassic was a case of accelerated turnover, with scarcely any decrease in overall diversity.

[2] Hence the name of the Floian. To be fair, the name could have been worse. The main competitor of Flo for the stratotype section was "The Ledge" on the Cow Head Peninsula of Newfoundland.

[3] The graptolites did not become extinct at that time -- or perhaps ever. We haven't done our homework on this one, but there is respectable opinion that the graptolites include the living pterobranch worms. See, for example, the citations at graptolite.net. Certainly, the graptolites lasted into the Mississippian.

[4] "... notre pays, réputé ingouvernable, capricieux, schizophrène ..." Yves Thréard, Le Figaro (Paris) 22/02/08. Bien sûr, avec raison, et depuis longtemps...

[5] B. triangularis had also been considered and rejected in favor of T. laevis during the 1995 selection of the Middle Ordovician guide event. Wang et al. (2005).

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