Natural history of Trinidad and Tobago hummingbirds to the primitive cave-dwelling oilbird (that uses sonar to fly in the dark) to the spectacularly beautiful scarlet ibis. The islands are within a few miles of Venezuela, and the species are therefore typical of tropical South America. However, the variety (although quite exceptional for such a small geographic area) is somewhat impoverished compared to the mainland, as would be expected with small islands. The resident breeding birds are augmented in the northern winter by migrants from North America. Tobago has only about half the number of bird species of Trinidad, but about 22 birds have been reported only
Geology of Trinidad and Tobago the North Coast Schist, mafic plutonic rocks, the Tobago Volcanic Group and mafic dikes. Geology of Trinidad and Tobago The geology of Trinidad includes two different islands with different rock forms. The oldest rocks in Trinidad are low-grade metamorphosed phyllite, limestone and quartzite from the late Jurassic. Cretaceous quartzite, phyllite, shale and limestone outcrops around the Toco district. The east of the island is the only area with volcanic rocks exposed at the surface, including basalt, ash and breccia. Phyllite shale spans the north coast. Laventille Formation limestone is associated with these rocks and contains a gypsum layer. Flysch, dark