Organic mound or biostrome rather than a wave-resistant bioherm or reef.
Binding predominates over framebuilding:
Encrusting forams, bryozoans and corals as binders.
Age based on Alpinophragmium perforatum Flügel
Non-segmented sponges more common than Sphinctozoa.
Tubiphytes, Bacinella, Cayeuxia, Panormidella, corals, Trepostomata as other important reef builders.