The Chicotte Formation (~90 m thick) is dominated by encrinitic and reefal limestones (Brunton & Copper 1994; Desrochers 2006; Desrochers et al.
Encrinitic FA-3 (Facies 1-3) in the basal Chicotte strata includes graded beds with sharp basal contacts, indicating sediment reworking and rapid deposition from episodic, high-energy storm events.
The exposures of the Huentelauquen Formation in the northern part of the study area (Munoz Cristi, 1942; Rebolledo and Charrier, 1994) consist mainly of gray and black shales, including encrinitic
The matrix consists of an encrinitic
packstone, containing many different planctonic foraminifera and red algae.
The lenticular limestone is succeeded by encrinitic
white limestone with trilobites, which marks the transition from the lower to middle Cambrian.