Note 78 — Chapter VI · THE PLAIN OF THE PAMPAS

While the Pampean deposits lie immediately on the crystalline and Paleozoic formations in the sierras of the lower Colorado and of the central Pampa, in the south of the province of Buenos Aires and in Uruguay, they are, on the eastern edge of the Sierra de Córdoba, separated from it by red sandstones and conglomerates of uncertain age, perhaps synchronous with the continental red sandstones of Corrientes which outcrop east of the Paraná and have been known since D'Orbigny's time as "granitic sandstones."