Abstract
The subsurface marine succession in the western Sirt Basin is normally underlain, in many places, by a sandstone unit known as the Bahi Formation. Lithologically, it commonly consists of sandstone and pebbly sandstone with a clay matrix and interbeds of siltstones, conglomerates, and shale, and its thickness varies from zero to a maximum of over 400 feet (Barr and Weegar, 1972). The Bahi Formation unconformably overlies various lower Palaeozoic rocks, mostly Cambro-Ordovician Hofra Formation (Orthoquartzites) and is overlain by marine sediments with a sharp and conformable to gradational contact.