Suborder:
|
Goniatitina
|
Superfamily:
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Schistoceratoidea
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Family:
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Christioceratidae
|
Genus:
|
Christioceras |
Qualifier:
|
ge |
Author:
|
Nassichuk & Furnish 1965,p.725
|
Lower Boundary:
|
Langsettian--Duckmantian, Westphal.A--B, 311.3 million years
|
Upper Boundary:
|
UTX Smithwick Fm. top, 308.6 million years
|