Conodonts are rare in the Martin Formation of central and southern Arizona and in the Portal Formation, southeastern Arizona. Although most are long ranging, species of Palmatolepis Ulrich and Bassler, Polygnathus Hinde, Ancyrognathus Branson and Mehl, and Ancyrodella Ulrich and Bassler indicate early Late Devonian age and permit comparison with other conodont faunas of North America and Europe. A few individuals from the uppermost Martin Formation at its type locality and the Percha Formation of New Mexico suggest age equivalence of these strata. Basal beds of the Escabrosa Formation (Kinderhookian) near Globe, Ariz., yielded Siphonodella isosticha Cooper which is additional evidence of the Mississippian age of this unit.

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