Large burrow structures attributable to the bivalve Archanodon are common in sandstones of the Towamensing Member of the Upper Devonian Catskill Formation in Pennsylvania and in its correlatives in New York and New Jersey. These structures show preferential curvature, cross-sectional ellipse parallelism, and internal asymmetric crescentic features. Vectorial analysis of these features has been based upon studies of the behavior of living specimens of Margaritifera margaritifera (L.).

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