The Eastern Alps extend about 500 kilometres in an east-west direction; at the Upper Rhine they pass westwards into the Western Alps, and at Vienna eastwards into the Carpathians, although this latter continuation is buried by the Mio-Pliocene Vienna Basin. Upon an Hercynian basement of metamorphic and sedimentary rocks, late Palaeozoic to earliest Tertiary sediments were deposited in a series of east-west trending facies-belts. Each belt has a complex depositional history, but in the northern belts there is generally a southward transition from thin, shallow-water deposits to thicker, deep-water deposits (i.e. north to south: Helvetic facies; Flysch facies; Schieferhülle, with local ophiolites). In contrast, however, the next adjacent belts to the south have thin shelf-deposits (Lower East Alpine facies, etc.), and pass southwards into very thick carbonates and reef complexes (Calc-Alpine facies). Rates of subsidence and sediment accumulation varied considerably between the different facies belts with time. In the mid-Cretaceous, thrusting and possibly strike-slip faulting (‘pre-Gosau movements’) occurred in the south within the Calc-Alpine rocks; these rocks were reburied within a short time by an unconformable cover of late-Cretaceous clastics (Gosau Beds). In the latest Cretaceous or early Tertiary, however, a series of regional thrust-sheets developed, transporting the more southerly facies-belts relatively northwards on top of each other, and on top of the more northerly belts. Thus, a pile of extensive but relatively thin superjacent sheets was formed within which the Mesozoic section may locally be repeated as many as four times. Present-day relationships are complicated by subsequent normal faulting. In early Tertiary times, after metamorphism of its lower parts, this pile was arched about an east-west axis, and coarse elastic debris was supplied to an Oligo-Miocene Molasse basin to the north. Erosion of this arched pile brought about thepresent-day regional outcrop pattern of east-west trending rock-units, modified locally in the axial zone by exposure of the lowest structural units in tectonic windows. The largest window, the Tauernfenster, exposes regionally metamorphosed (par-)autochthonous Pennine argillites (Schieferhülle) locally bearing kyanite and glaucophane, and resting upon Hercynian gneisses.