Eastern Chingiz-Tarbagatay volcanic belt.

Reefal facies in a 20 to 100 m-thick sequence of oolitic, sandy, clayey, clotted, massive and brecciated limestones, that crop out in craggy ranges for at least 100 km along strike, with an abundant biota that includes red and green algae, trilobites, brachiopods and gastropods. 

