Fig. 2

Orthoconic conch or siphuncle of a cephalopod (?Proterovaginoceras sp.) filled with diploporitans from the Ordovician (Darriwillian, Kunda stage, Holen limestone, upper Red Orthoceras Limestone) of Råbäcks in Västergötland province (Sweden); NRM Ec34704. A Detail of the specimen showing three thecae of Sphaeronites (Sphaeronites) sp.; note the pores and plate boundaries on the surface; the former sediment surface corresponds to the midline of the sedimentary filling of the cephalopod conch or siphuncle. Also note the darker colour of surface towards the bottom, probably caused by the darker sediment of the geopetal filling. B Detail showing four diploporitans, seen from above; the two diploporitans on the right are broken in the middle, revealing the syntaxial sparite fillings of the former void inside the theca. The entire specimen seen from the side (C) and from the top (D), i.e. looking down on the sediment surface