Paleontology and geology
The mid-Pacific chain of volcanic islands, reefs, and shoals that constitute the State of Hawaii began forming at a hot spot about 28 million years ago. Those older than five million years have largely sunk below the surface as they moved toward the northwest on the Pacific Plate. Marine fossils are known only from the Quaternary rocks of the main islands of Kauai, Oahu, Molokai, Lanai, and Maui. These fossils represent animals that lived on the seafloor during times when sea level was higher than it is now. Additionally, exposed Early Quaternary (Pleistocene) reefs built of calcareous algae, modern species of corals, molluscs, and foraminifera, occur along the shores of Oahu, especially along the Waianae coast. In addition to these marine fossils, bones of land birds are reported in Quaternary dunes and sinkholes. Many of these birds were flightless and extinct species of "geese," ibises, and rails that lived only in the Hawaiian Islands.