The depositional environment of Upper Silurian-Lower Devonian strata along the eastern margen of the
Paraná Basin, Brazil, is reconstructed. Sedimentological analyses are based on a detailed study of two basal
sections of the Furnas Formation in Paraná State. Sedimentation was initiated as an alluvial braided system,
as evindenced mainly by ridge and bar facies. This evolved into a deltaic complex including mounth bar
facies. The alluvial facies grades also laterally into a coastal marine deposits along a sinous shorelin
