Nummulites, starsands and conodonts

Fossils of life forms that are not visible to the naked eye, and therefore require microscopes to see are called microfossils. Microfossils include foraminifera with calcareous external shells called tests, calcareous nannoplankton, ostracoda, and radiolarian with siliceous shells, diatom and silicoflagellate, as well as fossil pollen and conodonts shaped like the teeth of fish. All of these require a microscope in order to identify their species. However, there are some foraminifera fossils like nummulites at 10 cm in diameter. The nummulites formed in Japan are limited to index fossils from the Eocene Epoch, Paleogene Period, Cenozoic Era. The star-shaped sand, called "star sand," found on the Nansei Islands and Okinawa are form of foraminifera. The known conodonts were formed between the beginning of the Paleozoic Era and the Triassic Period of the Mesozoic Era. Though their identity was unknown for a long time, they are now believed to be related to the lamprey. Microfossils are vital for all their small size, as some are index fossils that are ideal for determining geological age.