Inner shelf-margin buildups composed of thrombolitic limestone. 
Largest is at least 100 m thick and 2-3 km in diameter.
Zonation: Lowest are 1 mud mounds with composed thromboids and Conophyton-like stromatolites, then 2 cerebroform stromatolite facies, then 3 thrombolite facies with clotted core and stromatolitic margin, locally encrusted by lithistid sponges 4 large thrombolite facies with a columnar stromatolitic core.
Outer shelf interior buildups also present (reef. 2347).