Obere Onkoidbank, polished section; the lower half of dark grey limestone bed consists of redeposited, marginally eroded, micritic oncoids up to 7 × 8 cm in size. This part is overlain by silty, fine sandy, fossil-bearing (crinoids, bivalve shells, rare belemnites) marly limestone, in which up to 4 cm large oncoids with borings and thin pyritized microbial crusts are embedded. This sediment also fills the interspaces between the oncoids. Opalinuston Formation, Heiligenbach. Width of the photo: 20 cm.