The shell beds in the Ziarat Formation (Middle Eocene) have been distinguished into primarySokolowia
biogenic, fair-weather wave and proximal storm tempestite concentration of varied taphonomic and sedimentologic
characteristics. The existence of normal grading, sharp and erosional base in the uppermost part of the Ziarat Formation
indicate proximal tempestites between the storm wave-base and fair-weather wave-base. Disarticulated and intensely
fragmented shells were concentrated above the fair-weather wave-base. These are convex-up, exceedinglySokolowia
fragmented; poorly sorted large shells in calcareous marl were formed under strong hydrodynamic energy above the storm
weather base. Articulated shells in silty mudstone matrix, without fragmentation and abrasion, were accumulated in lagoon
environment attributing to in-situ concentration. These shell concentrations are recognized in distinct positions within the
depositional sequence of the Ziarat Formation.