Bolonia Meunier, 1886

Diagnosis:Horizontal to subhorizontal, non-branching, straight structures of variable diameter within a single specimen, occasionally tapering at the ends; bilobed, with median furrow; outline of cross-section trapezoidal to heart-shaped with elongate tip, somewhat similar to a gingko leaf. Trace fossil composed of biserial, subtriangular pads of sediment of inconstant thickness; pads inclined towards the bedding plane at an angle of about 30-45°. Top of trace fossil rarely shows an elliptical depression, which is slightly wider than the rest of the burrow, in respect to the long axis, and lacks distinct pads.

Description.-Angular meandering furrow preserved as an epirelief with narrow, rounded, lateral compression ridges on both sides. Two to 5 mm wide and 1 mm high. Slightly irregular marks across furrow, widest on crest of lateral ridges, caused by compression during peristaltic motion of animal.