This study provides the first record and description of the hydroid <i>Protulophila gestroi </i>Rovereto, 1901 from the Bohemian Cretaceous Basin (Czech Republic). The hydroid colony was bioclaustrated by a serpulid tube on the underside of a platy sponge, which is also encrusted by three species of bryozoans and an oyster. The Bohemian specimen differs from previously described specimens of <i>P. gestroi </i>in having zooidal orifices with broad sinuses

Five sedimentation episodes ranging from Upper Cenomanian to Lower Turonian (Korycany Member of the Peruc-Korycany Formation and Bílá Hora Formation) are documented from new outcrops at the Chrtníky quarry, Bohemian Cretaceous Basin (BCB). The first episode belongs to the lower <i>Metoicoceras geslinianum </i>Zone and is recorded only as phosphatic intraclasts in younger beds. The second and third episodes (upper <i>M. geslinianum </i>Zone) are represented by coarse conglomerates separated by an interval of condensed sedimentation, phosphogenesis, and erosion of incompletely lithified deposits. The third sedimentation episode is cut by erosion. Probably after a stratigraphic gap, a fourth episode followed and included further shaping of the underlying erosion surface (formation of a hardground s. lat.), stromatolite growth and phosphogenesis (second interval of condensed sedimentation), corrosion and redeposition of diabase clasts, calcareous mud deposition and firmground formation, and, finally, deposition of dark claystone and burrowing. This succession seems to be of Early Turonian age, <i>Whiteinella archaeocretacea </i>(?) Zone. Basal portions of the fifth sedimentation episode (Lower Turonian, <i>Helvetoglobotruncana helvetica </i>Zone) started after the erosion event and included marly deposits rich in macrofauna, whereas the overlying strata yield an impoverished fauna predominated by sponges. In the topmost part of the succession, fully oxic conditions with abundant macrofauna are documented. The biostratigraphic conclusions are based on macrofauna and micropalaeontology (palynomorphs and foraminifera), and on correlations with other shallow-water successions (Předboj, Velim, Pecínov). Finds of enormously abundant remains of the crinoid <i>Cyathidium </i>aff. <i>depressum </i>(Sieverts) are unique. Common bryozoan and microfossil associations document a deepening of the basin during the fifth sedimentation episode. An identical development is documented by gradual changes in ecologic types of sponges (<i>Pachytilodia bohemica</i> rarr;<i>Chonella</i>-<i>Verruculina</i>-<i>Siphonia</i> rarr;<i>Laocoetis</i>-<i>Guettardiscyphia-Diplodictyon </i>assemblages). The taphonomy of macrofauna supports previous views of the geological and sedimentological developments in the area. Nontronite, which causes the greenish colour of clay laminae mainly in stromatolites, was identified for the first time in the BCB

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