Triassic hallobia-bearing sandstone, and ophiolitic rocks (serpentinite, dolerite, basaltic volcanic rocks". Near the eastern edge of the basin, the Aksu Formation directly overlies the Triassic basement rocks along an angular unconformity. Less commonly, blocks of reefal limestone are present. These blocks contain fossils of the corals Stylophora, Helliastraea, Plesiastraea, Favia, Tarbellastraea, and Porites. Karpuzçay Formation With a maximum thickness of 1500 m, the Karpuzçay Formation is the single most extensive formation in the Aksu Basin. It is approximately equal in date to the Aksu Formation, also being dated to the Langhian and Tortonian based on fossils. It is either slightly older or slightly younger than the Aksu Formation; in either case, the two are mixed together in many places. The Karpuzçay Formation mostly comprises alternating layers of conglomerate, sandstone, and mudstone. The conglomerate layers have clasts made of chert, serpentinite, and various types of limestone. Sandstones vary in color from grey to green to dirty yellow. They have cross-bedding, cross-lamination, and pronounced graded bedding. Layers of tuffaceous sandstone are commonly mixed in with conglomerate or conglomeratic sandstone layers. Mudstone layers are usually laminated and contain concretions ranging from 15 to 20 mm. Gebiz Limestone The Gebiz Limestone unconformably overlies the Karpuzçay Formation at its type locality near the town of Gebiz in the southeastern part of the Aksu Basin. In some places along the basin's eastern edge, it is instead faulted against the Triassic-Jurassic rocks of the Antalya Complex. More within the basin, it is faulted against younger basement strata in some places. It is dated to the Upper Miocene, although the exact time period is disputed. It is variously dated to the Messinian or Tortonian. Its maximum thickness is about 40 m, in its type locality near the town of Gebiz. The Gebiz Limestone consists mainly of bioclastic limestone, marl, claystone, and mudstone. In some areas, there are reefal limestone deposits. The largest continuous exposed stretch of the Gebiz Limestone lies along the southeastern edge of the Aksu Basin; it runs parallel to the edge of the basin. Eskiköy Formation The main exposed outcroppings of the Eskiköy Formation are found in the middle part of the basin. Here, it generally sits on top of the Aksu and Karpuzçay Formations, separated from them by an unconformity. In some places, it instead lies on top of Triassic-Jurassic recrystallized limestones belonging to the Antalya Complex, either separated from them by an unconformity