Complex agglomeration of Lower Carboniferous mud mounds.
Mounds covering an area of 440 km2.
Maximum height 30 m, Basal diameter up to 300 m.
4 types:
1-2: crinoidal wacke-packstones with or without Stromatactis
3. Allochthonous
4. Biodetrital grainstone mounds
Mound growth from texanus-zone to bilineatus-zone (Asbian-Brigantian)