Echinoderm Stem Ossicles from the Permian Fort Apache Limestone East of Payson

Updated  10/30/17

 Sections of stems from stalked echinoderms are rare in the Fort Apache Limestone at all three of our sites east of Payson. This could include Crinoids, blastoids, and cystoids. There is really no way to identify the exact genus and species from scattered stem ossicles, so here I present to you anything that even remotely resembles a stem piece. The most common shapes are the small ovals with a round central axial hole, followed by more conventional round crinoid stem ossicles which are the larger sizes here. The extreme mud present on the bottom and raining down on the benthic community most likely prevented a large population of filter feeding crinoids from taking hold in this formation.

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 This represents a low power view of nearly every recognizable stem fragment we ever found in over 200 pounds of limestone. Some are round, some are star shaped. Many are ovals. A few ring shaped pieces are questionably stems, however they are included here for completeness. 7x

 Oval to round thick walled ossicles with very small central openings.

 Round doughnut shaped pieces with larger central round holes.

 Crinoid stem ossicles. These are single specimens.

 A three stack of crinoid ossicles, we can almost can call this one a stem!

 Side view of above specimen. The crinoids must have been quite diminutive.

 Very strange piece, a crinoid stem ossicle covered with an encrusting bryozoan. Few hard grounds existed in the Fort Apache, and we find quite a few shells, urchin parts and gastropods covered with such an encrustation.

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