MacLachlan mapped the La Victoria area in the period 1949 to 1951, accepting R. J. Smith's (1953) stratigraphic subdivisions. Shagam later demonstrated that the Paracotos formation of Smith contained within it a major unconformity and consigned the lower part of it to a new formation, the Tucutunemo, reserving the designation Paracotos formation for the upper portion characteristic of the type locality near the town of Paracotos.

The Tucutunemo formation lies conformably above the Las Mercedes formation of the Caracas group and hence is assigned as the uppermost formation in that group. Within this formation the Los Naranjos member, consisting in large part of flow breccias and tuffs, represents the beginning of volcanic activity accompanying the earliest stages of mountain building. The Villa de Cura group consisting largely of volcanic rocks is thought to lie above the Caracas group, but no contact between the two has been found. They are separated by a fault trough containing younger (Maestrichtian) Paracotos formation rocks.

The Tiara formation lavas postdate the main episode of metamorphism which has affected the Caracas and Villa de Cura groups but predate the Paracotos formation which contains Tiara pebbles.

Paleocene rocks lie unconformably upon the folded and slightly metamorphosed Paracotos formation.

Hornblende-quartz diorite and sodic granite intrude Caracas group rocks and are metamorphosed with them. Serpentinized peridotites occur along the Paracotos fault trough and are at least in part emplaced as solid intrusions. Gabbro intrusions also are found along this trough.

The structure is complicated in detail but comparatively simple in broad aspect.

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