• WordNet 3.6
    • n Ordovician from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds
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Webster's Revised Unabridged Dictionary
    • a Ordovician (Geol) Of or pertaining to a division of the Silurian formation, corresponding in general to the Lower Silurian of most authors, exclusive of the Cambrian.
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Century Dictionary and Cyclopedia
    • Ordovician An epithet applied by C. Lapworth to a series of rocks not capable of exact separation from those underlying or overlying them, either stratigraphically or paleontologically, but which have been the subject of much discussion among English geologists. They form a part of the Lower Silurian of Murchison, more or less of the Upper Cambrian of Sedgwick, the Cambro-Silurian of Jukes, the Siluro-Cambrian of some authors, the second fauna of Barrande, etc. As limited in Wales, according to H. B. Woodward, the Ordovician may be said to extend from the base of the Arenig series to the base of the Llandovery. Graptolites and trilobites are the most abundant fossils, and there is a large amount of intercalated volcanic material. The name Ordovician does not appear in the text-book of geology recently issued by the director of the Geological Survey of Great Britain, nor has it any place in American Silurian geology as worked out by the New York and Pennsylvania Surveys, nor can the strata thus named in England be strictly parallelized with any one or more divisions of the Silurian as established in the United States.
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Webster's Revised Unabridged Dictionary
From L. Ordovices, a Celtic people in Wales


In literature:

The levelling continues through the next (Ordovician) period.
"The Story of Evolution" by Joseph McCabe
A small patch of Ordovician strata lies on the northern side of Beaumaris.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1" by Various
The series is now placed at the top of the Ordovician System, above the Llandeilo beds.
"Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 2" by Various
Ordovician beds probably occur also in the Kuen-lun.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 2" by Various
The strata of this system rest upon the Pre-Cambrian, and are succeeded by the Ordovician system.
"Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 1" by Various
The Palaeozoic beds have yielded fossils of Cambrian, Ordovician, Devonian and Carboniferous age.
"Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 2" by Various
They are followed by another series called the Ordovician; and that by another the Silurian.
"The Geological Story of the Isle of Wight" by J. Cecil Hughes
Contemporaneous volcanic rocks are associated with the Ordovician beds and with the Rhaetic sandstones in several places.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5" by Various
Besides the plant beds extensive outflows of basic lava rest directly upon the Cambrian and Ordovician strata.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 7" by Various
The breaking up of the old Archean foundation block began in Cambrian and Ordovician times.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 8" by Various

In news:

The Tihalatine Sud-1 (TIHS-1) well was drilled to a depth of 1,192 meters in the Ordovician shale.
The Gapowo B-1 well on the Bytow concession in Poland encountered overpressured shales in Lower Silurian and Ordovician and greatly elevated gas readings over those in wells on the Saponis concessions.
Whiting Petroleum Corp. Denver, said it has identified more than 50 vertical Red River prospects at its Big Island Ordovician Red River oil and gas play in Golden Valley County, ND, in the Williston basin.
A self-redirected Talisman Energy Inc expressed encouragement earlier this month at results from its first well in Ordovician Utica shale in Quebec's St Lawrence Lowlands.

In science:

Myr bp, in late Ordovician and Silurian period.
Statistical Approach to Gene Evolution
Seekers after extended mnemonics for the sequence of spectral types may wish to make use of longlived tortoises, for instance in the form, Ordovician Barnacles And Fossil Gastropods Killed My Long-lived Tortoise Yesterday.
Astrophysics in 2006