Peritidal zone deposits consist of dark carbonaceous mudstones-wackestones and dolomitised laminated algal boundstone beds. Secondary Fe-calcite camouflaged the original depositional texture in some parts. Fossils include Schubertella, Girvanella and Gyroporella algae, Hemigordius, Globivalvulina sp. along with other microscopic non-fusuline foraminifera. Peritidal settings were interpreted within Logs 1 and 4 with ages constrained between the late Murgabian to Midian.
Platform interior contains three sub-environments: lagoon, the outer platform and the higher energy backreef. The low-energy lagoon is comprised of bioturbated skeletal and peloidal wackestones and packstones with localised interbedded shales. The fossil assemblage contained abundant algae including Girvanella, bivalves (including alatoconchids), fusulinids (N. simplex) and microscopic non-fusuline foraminifera (Globivalvulina, Schubertella, Cribogenerina and Textulariida). The lagoonal environment is interpreted for lower Log 4 and upper Log 6 and deposited in the Murgabian with possible extension into the Midian.
The outer platform sub-environment is a non-parallel bedded bioclastic limestone grading from wackestone through to grainstone with boundstone interbeds. Isolated coral clumps were also observed within the grainstone sections. Inner platform settings were interpreted within Logs 1, 2, 5, 7 and 8. The age of the environment was constrained using the fusuline foraminifera (Neoschwagerina simplex, other Neoschwagerina sp., Neofusulinella, Nankinella, Kahlerina, Armenina). The fossil assemblages gave an age within the Murgabian Stage.
The higher-energy backreef sub-environment is defined by parallel bedded wackestones and packstones. Backreef settings are interpreted within Logs 5, 6 and 8. Each major fossil group is present in the Highway 21 backreefs: crinoids, fusulinids (Nankinella, Schwagerina, Colania, Neoschwagerina and Gifuella), bivalves (Alatyoconda), non-fusuline foraminif