The Trinidad Mountains in south-central Cuba include the San Juan, Trinidad, and Banao-Sancti Spiritus Mountains. The mountain system has steep south and west slopes and gentle north and east slopes. Karst topography characterizes the areas which are underlain by limestone.

The oldest rocks are Middle Jurassic (pre-Oxfordian) metasediments with micaschists at the base of the section and carbonate rocks above. Tentative correlation suggests the presence of a geosyncline during Middle Jurassic time. The metasediments are overlain unconformably by Middle to lower Upper Cretaceous sediments and pyroclastics (Albian to Santonian). Both are intruded by basic and acidic plutonics of middle Upper Cretaceous (pre-Maestrichtian) age. Sediments of younger Cretaceous and Tertiary age cover the margins of the mountain system.

At the close of the Lower Cretaceous, compressive forces oriented north-south, produced isoclinal folds and elevated the original Trinidad Mountains. Renewed orogenic activity during the middle Upper Cretaceous was accompanied by additional folding, cross-faulting, and jointing. Later intrusion of pyroxenites and periodotites was followed by acidic differentiates. At the end of the lower Eocene, tangential forces oriented southward produced a series of major overthrusts on the north coast of Las Villas Province and reverse structures in the Trinidad Mountains. Left-lateral strike-slip normal faults on the southwest margin of the mountains were developed during early Miocene time. They are part of a shear zone crossing Cuba in a northwest-southeast trend from the Bay of Cardenas to Cie fuegos.

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