The Vihowa and Chitarwata Formations in the Dalana area of the Zinda Pir Dome record a significant interval in the history of mammalian evolution. We interpret the base of the Vihowa Formation in the southern end of the Zinda Pir Dome to occur in Chron 6n (about 19.5 Ma), at least a million years older than the base of the Siwalik sequence to the northeast in the Potwar Plateau. We measured the Chitarwata Formation in its type area, finding it significantly thicker then initially described, and characterized the basal part of the Chitarwata Formation as densely burrowed nearshore sands.
Upper levels of the Chitarwata Formation near Dalana are early Miocene in age; lower levels are Oligocene. Elements typical of the early Miocene Kamlial fauna of the Siwalik Group occur in early Miocene horizons of the Dalana area. Many of the lineages that occur in the upper part of the Chitarwata Formation also occur in the lower part of the overlying Vihowa Formation, suggesting that a minor hiatus separates these two bodies of rock. The upper unit of the Chitarwata Formation appears to encompass hiatuses, and this is reflected in faunal differences. Low in the upper unit, the appearance of proboscideans is dated as earliest Miocene (close to 23 Ma, in Chron 6Bn) or late Oligocene (Chron 8n), depending on correlation to the GPTS. Primitive species of early Miocene rodent lineages (sciurids, rhizomyids, cricetids, and ctenodactylids) appear near the base of the upper unit (localities Z113 and Z139) that is considered late Oligocene, about 27 or 23.5 Ma, depending on correlation to the GPTS.
The middle unit of the Chitarwata Formation has produced no terrestrial vertebrate fossils and represents strandline deposits; its paleomagnetic signal is too weak to interpret with confidence. The lower unit of the Chitarwata Formation is over 100 m thick, and therefore may span considerable time; it is Oligocene in age. This interval preserves baluchimyine rodents and indricothere rhinos. Small mammals from locality Z108 resemble those from Bugti localities Y417 and Paali, although Flynn and Cheema (1994) argued Z108 might be younger. Two alternative correlations to the GPTS place Z108 as early Oligocene, about 28.5 Ma, or late Oligocene, about 25 Ma. The former conclusion is consistent with the hypothesis of Marivaux et al. (1999) that the famous Bugti Bone Beds are early Oligocene.