Ion Formation
171 distinct taxa, from 397 fossil occurrences the Paleobiology Database records under this name, spanning 457–450 Mya.
Illinois, Iowa, Iowa, Illinois, Iowa, Wisconsin, Minnesota, Iowa, Wisconsin, Illinois · US
171 taxa · 397 fossils · 457–450 MyaFiled under the Galena Group. Members recorded: Buckhorn, St. James.
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4 distinct localities, where the rock is now rather than where it was laid down. Tectonics draws the world it belonged to.
When
What has been found
- Aparchites
- Dicranella
- Saccelatia
- Byrsolopsina
- Euprimitia
- Eurychilina
- Leperditella
- Parabolbina
- Winchellatia
- Carabocrinus
- Ceratopsis
- Clathrospira conica
- Cryptophyllus
- Hallatia
- Krausella
- Maratia
- Parenthatia
- Pedomphalella
- Porocrinus
- Primitiella
- Schmidtella
- Hemicystites
- Manitoulinoceras
- Michelinoceras
- Petrocrania
- Rhynchotrema
- Tetradella
- Acanthocrania setigera
- Aechmina
- Amecystis woodi
- Anazyga recurvirostra
- Archinacella deleta
- Aristerella
- Bassleratia
- Batostoma
- Bellornatia
- Bollia
- Bromidella
- Bullatella
- Bythocypris
The 40 most often recorded, of 171.
What else lived thenRank the rock of a period
Counts are of occurrence records, which measure the rock and the fieldwork together.