New Mexico’s vast expanses contain extensive outcrops of rocks where fossils occur. These sedimentary, or layered rocks, are where most fossils are preserved, sometimes in great abundance. New Mexico is well known by paleontologists worldwide in having rocks of variable ages that contain important fossils. New Mexico is fortunate in having rocks preserved from every period and epoch of time. Fossils have been collected from all of these periods and epochs. No fossils have been found in Precambrian rocks in New Mexico.
Early Paleozoic rocks, containing mostly invertebrates, are restricted to southern New Mexico. These invertebrates include trilobites, brachiopods, gastropods (snails), corals, nautiloids and others. Along with the previously mentioned fossils, crinoids, fish, and primitive conifers have been found in Pennsylvanian rocks of the Late Paleozoic of New Mexico. Important vertebrates, trackways and plants have been collected in the state from Permian rocks of the latest Paleozoic. Triassic rocks, marking the beginning of the Mesozoic era, are plentiful in New Mexico, mostly in the northern half of the state. Many world class finds have been made from Triassic rocks in the state. The most famous being the Coelophysis quarry at Ghost Ranch. No Triassic marine rocks are present in New Mexico. In more recent times, important fossil finds have been made from Jurassic rocks in New Mexico. Some of the most notable include the Peterson Quarry, which has produced several Jurassic dinosaurs and Diplodocus hallorum (Seismosaurus) a sauropod reaching about 110 feet long. Cretaceous rocks, some of thickest in the state, are widespread. They include both terrestrial and marine deposits. Several important Cretaceous dinosaur finds have been made in the state including Pentaceratops,Bistahieversor sealeyi, Spaerotholus goodwini, Nodocephalosaurus and others. Ammonites, gastropods, pelecypods (mollusks) and plants are abundant fossils in New Mexico. Mosasaur (marine reptiles) remains, although not abundant, have been recovered from the state. The beginning of the Cenozoic era and Tertiary period is marked by the Paleocene epoch. Many important Paleocene fossils have been collected from the state. In fact, Paleocene faunas in New Mexico are referenced as an international standard. Likewise, Eocene faunas from New Mexico have also been referenced as an international standard. Many important Miocene and Pliocene fossils have been collected from New Mexico. The American Museum of Natural History in New York houses multitudinous Miocene fossils that they collected during a forty year period that ended in the 1960s. Some of the most famous Pleistocene fossils collected from New Mexico include those collected from Blackwater Draw in eastern New Mexico and bison from the Folsom site in northeastern New Mexico.
Many world class finds have been made in New Mexico. Many famous fossil hunters have collected fossils in New Mexico. They include Jules Marcou, Edward Drinker Cope, David Baldwin, Charles Sternberg, William Cobban, Childs Frick, and others. I will elaborate on some of their fossils finds in various sections of the website. Several famous institutions, such as the Smithsonian and American Museum of Natural History, house many fossils that were collected from New Mexico.