The central part of the buildup is formed by coral bafflestone, partly overlain
by brachiopod-rich facies III. The buildup is formed by several pillow-shaped units. The transition
to surrounding bedded facies V is gradual. The buildup framework is formed by complete, in situ colonies of rugose and tabulate corals, stromatoporoids and branching bryozoans. The sediment baffled between the framework builders consists of very poorly sorted echinoderm ossicles, brachiopods and rare ?Dimorphosiphon fragments, but the buildup fabric is distinguished by a high (ca 50%) micritic matrix. Allonema and Rothpletzellaare present as crusts and Rothpletzella also as loose
accumulations within the matrix. These are associated with mottled, peloidal-like structures containing
structures tentatively identified as sponge spicules. The mottled fabrics contain multiple small
(up to 0.4 cm wide) stromatactis-like cavities filled with spar, characterized by sharp basal parts and irregular undulating upper parts. In SEM images, oncoids and Rothpletzella
accumulations floating in the matrix are built by tubes filled with sparitic cement. The tube walls
are 5-6 µm thick, formed by regularly arranged needleshaped calcite crystals oriented perpendicular to the porostromate tube in longitudinal sections and radially in cross sections. In contrast, the mottled, peloidal matrix of facies IV is composed of chaotically arranged microcrystalline calcareous mud containing a high proportion of clay particles and scattered fragments of skeletal grains. The buildup is overlain by nodular wacke- to packstones composed of well-sorted echinoderm,
brachiopod, gastropod, trilobite and coral fragments (facies V) and onlapping the units represented by
facies II, III and IV.