INTRODUCTION The latest comprehensive report on the general and economic geology of Trinidad is that of H. H. Suter (1951). It is a concisely written, well-illustrated account with an almost complete bibliography and should be referred to for greater details. H. G. Kugler (1953) elaborates in a subsequent paper on the interrelation of litho-, bio-, and tecto-facies with special attention to gravitational flow of sediments and the exogenous origin of large slip masses. The restricted scope of this sketch cannot give credit to the great deal of information available, but an attempt is made to draw attention to some of the features for which the island has become well known among geologists and paleontologists. Plate 1 is a geologic map and section of the island. STRATIGRAPHY The inadvisability of applying European stage names for any epoch younger than Eocene has been realized and has rendered it necessary to introduce a stratigraphy built up on biozones based mainly on pelagic Foraminifera (Table 1). PRE-CRETACEOUS The metamorphosed rocks of the “Caribbean group” of the Northern Range were considered to be of Paleozoic age until Mesozoic fossil remains were found in the Laventille limestone. The subsequent discovery of several specimens of Perisphinctes transitorius in the lenticular limestones of the Cuare Dam indicated a Tithonian age for that part of the group. On account of the general eastward plunge of the Northern Range the oldest formations should be expected to the west, and in fact were found as early as 1860 by Wall at