Cladichnus fisheri (Heer, 1877)

Description. Endichnial trace fossils composed of meniscate, branched, horizontal to inclined, straight or rarely slightly curved flattened tunnels radiating from a vertical axial zone. The tunnels are 2-5 mm wide and 40-90 mm long.Their termination is semi-circular. C. fischeri occurs in marlstones and is filled with dark argillaceous material of the background sediment derived from the top of the bed. The convex side of the menisci is oriented outward. The menisci are about 2 mm thick and located 1.0-1.5 mm apart. They are of slightly larger size than the inter-menisci intervals, up to about 1 mm at each side, and the margin of the tunnels therefore is slightly lobate. In some specimens, the menisci are only visible in one part of the burrow system, and in the other part the filling became gradually massive (locality no. 20). Almost exclusively only second-order branches have been noted. Very rarely third-order branches occur; they branch at an angle of 30-45. The whole burrow system is 60-130 mm across.