Some Ordovician Rocks


Thetford Mines Ophiolite Complex - Ordovician serpentinite from Thetford Mines, Quebec, Canada.



Glover Bluff Impact Breccia, Oneota Formation - Lower Ordovician impact breccia from the Glover Bluff Impact Crater, Wisconsin, USA.



Bendigonian Formation - fossiliferous clayshale with carbonized Tetragraptus fossil graptolites from the Lower Ordovician at Spring Gully, Bendigo, Victoria, Australia.



Sandamap Pegmatite - ~470 Ma purpurite (~Early-Middle Ordovician boundary times) from the Southern Tin Belt, Namibia.



Fazenda Memória Stock (“Alaskan White Granite”) - porphyritic garnetiferous leucogranite from the Middle Ordovician (~466 Ma) at Fazenda Memória, Ceará State, Brazil.



Mynydd Preselii Dolerite Suite - spotted metadolerite (early Middle Ordovician) from the Preseli Hills of Wales in Britain.



St. Peter Sandstone - white, clean, quartz arenite (quartzose sandstone) (Middle Ordovician) from Kentland Dome Impact Structure, Indiana, USA.



Blakely Sandstone - quartzose sandstone from the Middle Ordovician at Coleman Quartz Mine, Arkansas, USA.



Cloridorme Formation - silty mudrock with flute casts in a turbidite succession from the Middle Ordovician (Caradocian) at St. Yvon, Quebec, Canada.



Lower Hartfell Shales - fossiliferous black shale with Climacograptus wilsoni graptolites (~mid-Caradocian, upper Middle Ordovician) from Dob's Linn, Southern Uplands, Scotland, northern Britain.



Galena Formation - fossiliferous limestone with Hormotoma fossil snail (upper Middle Ordovician to lower Upper Ordovician) from eastern Iowa, USA.



Lockne Breccia - impact resurge breccia from the Upper Ordovician (~455-458 Ma) at Lockne Impact Crater, Sweden.



Kope Formation - fossiliferous packstone (lower Upper Ordovician) with abundant crinoid stem columnals plus tentaculites, bryozoans, and trilobite fragments (= chocolate brown-colored pieces) from near Cincinnati, northern Kentucky, USA.



Collingwood Member of the Lindsay Formation (Cobourg Formation/Whitby Formation) - black shale (Upper Ordovician) with Pseudogygites latimarginatus and Triarthrus eatoni trilobite sclerites from St. Mary's Cement Company Quarry at Bowmanville, Ontario, Canada.



Bellevue Limestone - fossiliferous limestones with Streptaster vorticellatus edrioasteroid (left) and Carneyella ulrichi edrioasteroid (right)  (middle Upper Ordovician) from near Maysville, Kentucky, USA.



Arnheim Formation - fossiliferous shale with Isotelus maximus trilobite (upper Upper Ordovician) from Flat Run, Mt. Orab, Ohio, USA.



Liberty Formation - fossiliferous wackestone with hexaradial mutant of Promopalaeaster fossil starfish (upper Upper Ordovician) from Caesar Creek Lake's emergency spillway, Warren County, Ohio, USA.



Whitewater Formation - fossiliferous packstone with Xenocrinus crinoids (upper Upper Ordovician) from Flat Fork, Warren County, Ohio, USA.




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