Framing geoheritage thematically is important to reveal its diversity. Field investigations in the western part of the Greater Caucasus orogen have allowed for the characterization of three localities representing palaeoislands of the Caucasian Sea, which evolved as a semi-enclosed, marginal palaeosea during the Mesozoic. The Gosh locality represents coarse siliciclastics formed on the cliffed shore of the early Induan (Early Triassic) island. The Lipovy locality exhibits conglomerates accumulated on the shore of the early Toarcian (Early Jurassic) island due to erosion of the uplifted crystalline rocks. The Shakhan locality boasts a representative section of cross-bedded sandstones deposited on the alluvial plain of the Hauterivian (Early Cretaceous) island. All these localities are interpreted as geoheritage points, which are parts of larger geosites. Taken together, these points constitute thematic geoheritage sites reflecting the existence of palaeoislands in all Mesozoic periods, which is essential for the understanding of the evolution of the Caucasian Sea during this era. These localities are perfectly accessible, but visiting them requires professional interpretation. The importance of the thematic geoheritage makes its adequate management urgent (particularly, maintenance of geoheritage points, the installation of interpretive panels, and promotion). A geoexcursion route is proposed to facilitate geotouristic exploitation of the characterized geoheritage sites.