Figure 32. Perchel – Huacalera area (Northern Tilcara Range). An impressive and continuous Tremadocian succession. References for stratigraphic column, see Mojotoro, Figure 2.

Figure 33. The Iruya unconformity with the basal conglomerate of the Santa Victoria Group, located to the north of Tilcara.

Figure 37. Angosto de La Quesera area. Location map and stratigraphic column of Tremadocian units. References for stratigraphic column, see Mojotoro, Figure 2.

Figure 38. Angosto de la Quesera section of the Ordovician succession (SVG).

Figure 39. Basal conglomerate of Saladillo Formation at Angosto de la Quesera locality.

Figure 40. Chrono–biostratigraphic chart of the Ordovician System (after Albanesi and Ortega, 2002).