In contributions to Venezuelan geology the tendency has been to regard the Tertiary as disconformable on the Cretaceous and as rather closely succeeding it in depositional sequence.

The Eocene-Cretaceous contact is exposed at several localities in western Venezuela. At some of these the relation is one of marked angularity, particularly in the state of Tachira and on the southern flanks of the Andean chain. On the north side of the mountains the relation is more obscure with the exception of the locality near Los Algodones in the northern part of the state of Lara. Here the exposure is very definite, with basal conglomerate of the Eocene resting upon the vertical eroded edges of the Cretaceous.

The Tertiary section from here north is complete, well exposed, and definitely determinate, and the underlying Cretaceous rocks are, in turn, definitely continuous with the Cretacous formations which flank the mountains on their north side.

The unconformity is of such marked discordance that a distinctly unconformable relation between the basal Eocene and the Cretaceous throughout Venezuela is indicated. A very considerable uplift at the close of Cretaceous time with a consequent long period of erosion preceded the deposition of the earliest Eocene sediments.