| Series | Stage | N.A. substage | Russian (Primorye) substage | Canadian Zone (Western U.S.) |
Russian (Primorye) Zone |
| Lower Triassic | Olenekian |
Spathian | Russian | Subrobustus (Neopopanoceras haugi) |
Subcolumbites multiformis |
| Pilaticus (Prohungarites -Subcolumbites beds) | Neocolumbite insignis | ||||
| Ayaxian | (Columbites-Tirolites beds) | Tirolites - Amphistephanites | |||
| Smithian | Tardus (Anasibirites Beds) |
Anasibirites nevolini | |||
| Romunderi (Meekoceras gracilitatis Zone) |
Hedenstroemia bosphorensis | ||||
| Induan |
|||||
Stratigraphy
The
Olenekian is the approved Global Stage name for the Upper Lower
Triassic. Substages and biozones are recognized in the Far East
and North America. The Hedenstroemia bosphorensis Zone of
Southern Primorye (Russia) = the Romunderi Zone of Canada and the
Western U.S. (Meekoceras Beds), and the Anasibirites nevolini Zone of
Southern Primorye (Russia) = the Tardus Zone of Canada and the
Western U.S. (Anasibirites Beds). The IUGS and it's
subcommissions are working on setting global boundarys and names for
these divisions.
Taxonomy (Lumper or Splitter?)
As for
Smithian Taxonomy on this web page, all ammonoids are nominal.
Because
of the variable morphology in some populations all specimens are a
seperate species, or all are one specie with variable morphology.
Mathews (1929) described (a) 32 species of Anasibirites, 5
species of Gurlyeites, 9 of Hemiprionites "Goniodiscus"
and 1 of Kashmirites, and (b) 4 species
of Wasatchites, 3 of Kashmirites and 1 of Keyserlingites,
from Cephalopod Gulch near Salt Lake City, Utah. Later workers
placed alot of them (a) in synonomy with Anasibirites kingianus
(Waagen) and (b) in Wasatchites. In the Anasibirites Beds
(about 300mm thick) of the Confusion Range of western Utah. there are
representatives of all these genera, they grade from
Hemiprionites to Anasibirites to Gurleyites to Wasatchites
with intermediates between each. To use a typological taxonomy
would
mean many new species, to use a population taxonomy would mean one or
two
species. Given the short duration of the Smithian and the
difference
between the faunas of the Romunderi and Tardus zones it seems best to
refer
all to nominal species (with generic modifiers in quotes on some just
to
tell what the specimen looks like). So for the time being
Prionitid
ammonoids from the Anasibirites beds on this site are lumped into two
species,
Anasibirites kingianus (Waagen) 1895, and Wasatchites perrini
(Mathews) 1929. (See the two papers by E.T. Tozer 1971 and 1994
for
more). Ammonoids from the Meekoceras beds and Inyoites beds on
this
site are likewise refered to nominal genera or species.