Abstract: The Carboniferous stratigraphy of İstanbul is describedwith special reference to the western part of Bosporus (Thracianarea). On the basis of particular stratigraphic successions ,andstructural features the Thracian area is subdividied in subareas of Istinye, Kâğıthane, Cebeciköy ,and Zekeriyaköy.The upper part of a predominantly nodular limestone unit(Büyükada fm.) is subdivided in two members, in ancendingorder: Ayineburnu ,and Küçükyalı. The Ayineburnu member iscomposed of thin-to medium - bedded nodular limestone ,andlaminated calcareous shales ,and ranges from Late Devonian toEarly Tournaisian in age. İt conformably overlaps the older Devonian strata on Ordovician rocks. The Küçükyalı member isrepresented by channel-filled turbidite graywacke ,and shale. TheBaltalimanı formation is mainly composed of lydites ,and subordinate siliceous shales. İt is Early / Middle Tournisian, / both,in age. The Trakya formation is characterized by thick shales,graywackes ,and lithic - conglomerates which are highly variableboth lateraly ,and vertically. The flysch facies, anyway interrupted, is predominant. On the basis of fine- ,and coarse-clastics ,anddistribution of carbonates the Trakya formation is subdividedin three members, in ascending order: Acıbadem, Küçükköy ,and Çamurluhan. The formation ranges from Late Tour-naisian to nearly Late Middle Visean in age. The Acıbadem memberconsists of shale ,and claystone with limestones intercalated.The Küçükköy member is composed of shales, thick-beddedgraywackes, lithic-conglomerates ,and subordinate limestones.The Çamurluhan member is mainly made up of shales with graywckes, lithic-and quartz - conglomerates, ,and limestones. Theshales become sandier ,and pebbly toward the north. The thickness, the biofacies, likewise change in the same direction. Atthe north, the shales are the time equivalent of the lower part ofthe overlying Cebeciköy limestone. The Cebeciköy limestone İscomposed of bioclastic limestone, subordinate shales, secondary dolomite ,and chert. The unit is of shelf-edge carbonate type ,and is Late Middle to Middle Late Visean in age. The Gümüşdere formation consists of graywacke, feldispathic garywacke,feldispathic conglomerate, shale ,and Iydite. The basal siliceousshale ,and Iydite designated the Kartaltepe member. İn the souththe siliceous shales predominate which gradationally overlie theCebeciköy limestone. İn the north, the lydites discordantly reston the lower sections of the Çamurluhan member. The flora ofthe member is in favor of a Late Visean- Namurian age. The maingraywacke section of the formation is of flysch facies. Minorcoal seams are present in the uppermost part of the formation.The Çiftalan formation consists of medium-to thick - bedded,subgraywackes. İt strikes parallel with the Gümüşdere formation ,and bears some compositional similarity to it. The Değirmendere formation consists of aphanitic limestone, clayey limestone ,and intraformational limestone - breccia. Secondary dolomitization is widespread. The poor microfauna bears the commonelements for Carboniferous ,and Permian. The Uskumruköy formation is composed of reddish shales, at its base ,and pebblygraywackes, on its higher section. The contact to the underlying limestone is obscured. Some coalified plant remnants occursparodically in the sandstones.İn the Thracian area the late Laramide phases appear to havebeen responsible for a large part of the deformation. Three Alpine stages are differentiated, in relative age : (a) overturnedfolds, steep thrust faults which are arranged along a WNW linemay be virtually connected with the thrusting towards the north- Zekeriyaköy overthrust-, (b) mosaic-fault system, resulted inby the release tectonic, (c) sinistral strike-slip faults with the NEtrend. The N trends, more / less separated from the Alpine features, can be attributed to the Varistic.