Permo-Carboniferous fresh water burrows

Burrow-casts from fresh-water deposits of the Late Paleozoic have given concrete evidence of the aestivation of the lungfish, Gnathorhiza, and the amphibian, Lysorophus. The structure of these burrows and inference concerning the life habits of their occupants are analyzed, with special attention to Lysorophus. A previously unknown type of burrow, found in association with those of lung fish is described. It is a large, complex structure, ovoid in cross-section and oriented vertically in the surrounding sediments. By elimination it seems most probable that it was formed by some type of large crustacean, but the precise origin remains uncertain.