Periodo Ordovícico
Platystrophia sp. L. 14 mm.

Cincinnati Grp. Cincinnati, Ohio. Estados Unidos.

Rhynchotrema sp (Hall 1860) L. 9 mm.

Verulam Fm. Gamebridge, Ontario. Canada

Rhynchotrema sp (Hall 1860) L. 10 mm.

Verulam Fm. Gamebridge, Ontario. Canada

Rafinesquina alternata (Conrad 1838) L. 32 mm.

Cincinnati Grp. Cincinnati, Ohio. Estados Unidos

Shoshonorthis michaelis (Clark 1935) L. 6 mm.

Kanosh Fm. Ibex, Utah. Estados Unidos

Strophomena sp. L. 17 mm.

Cincinnati Grp. Cincinnati, Ohio. USA

Sowerbyella rugosa (Meek 1873) L. 9 mm.

Kope Fm. Newport, Kent. Estados Unidos

Sowerbyella rugosa (Meek 1873) L. 9 mm.

Kope Fm. Newport, Kent. Estados Unidos

Cincinnetina meeki (Miller, 1875) L. 17,5 mm.

Waynesville Formation, Richmond Group. Late Ordovician (Katian). Cincinnati area, Ohio, Indiana, USA

Sowerbyella curdsvillensis (Foerste 1912)

Decorah Formation. Late Ordovician (Sandbian) Route MM. Jefferson County, Missouri. USA

Zygospira recurvirostris (Hall, 1847)

Decorah Formation, Late Ordovician (Sandbian), Route MM, Jefferson County, Missouri. USA

Leptaena sp L. 19,6 mm.

Ordovician to the Mississippian in the US.

Leptaena sp. L. 19 mm.

Ordovician to the Mississippian in the US.

Pionodema subaequata (Conrad 1843) L. 11,5 mm.

Dunleith Formation, Kimmswick Subgroup, Late Ordovician (Katian). Route M. Jefferson County, Missouri, USA

Pionodema subaequata (Conrad 1843) L. 18,3 mm.

Decorah Formation. Late Ordovician (Sandbian) Route MM. Jefferson County, Missouri. USA

Periodos