Caballo Island Caballo Island Caballo Island (which means "Horse Island" in Spanish) is a bluff, rocky island located at the entrance to Manila Bay in the Philippines. It is about long with the highest elevation at 381 feet high. Caballo, along with the larger Corregidor (2 km to the north), divides the entrance to the bay into two broad and deep channels, known as the North and South Channel. The whole island was formerly occupied by Fort Hughes, a U.S. defense fortification before World War II. It was heavily bombed during the war. Caballo and Corregidor Islands are believed to be the
Caballo Mountains Nakaye Formation of limestone, the Bar B Formation of interbedded limestone, dolomite, shale, and conglomerate, and the red shale beds of the Abo Formation. All of those strata are Pennsylvanian in age. Above them is thePermian Yeso Formation, which consists of sandstones, siltstone-dolomites, and limestones. The Paleozoic strata are completed by the Meseta Blanca Sandstone. Most of the Mesozoic rocks are missing from the Caballo geological history. A second unconformity lies above the Meseta Blanca Sandstone, and includes all of the Triassic and Jurassic periods. The next oldest rocks are of Cretaceous age and include: The Mesozoic rocks terminate below