[Hyolithes princeps]
This is a double of the rare Hyolith species Nevadotheca princeps from the lower Cambrian of Nevada.
This species was first described in 1872 by Billings from the Cambrian of Mexico as Hyolithes princeps. In the year 1886 Dr. Walcott has recorded this species also from the site Silver Peak in Nevada. The species was in 1990 assigned to the genus Nevadotheca by J. M. Malinky. That genus was already established Resser in 1938.

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