(A) Outcrop view of studied zone (north Picún Leufú Anticline); (B) General aspect of grey laminated shales (Facies 2); (C) Facies association 1 corresponding to massive and laminated grey shales (F2.a and F2.b, respectively) with rare fine-grained sandstones (Facies 5); (D) Detail of dark shales (Facies 1); (E) Well-preserved ammonoid horizon recognized at the base of the measured sections; (F) Detail of laminated grey shales (Facies 2b); (G) General aspect of green massive shales (Facies 3a); (H) Detail of green massive shales (Facies 3a).