Fossils & Geologic Time, SIV-ZIT
Geologic time is the extensive interval of time occupied by the geologic history of Earth. Formal geologic time begins at the start of the Archean Eon (4.0 billion to 2.5 billion years ago) and continues to the present day.
Fossils & Geologic Time Encyclopedia Articles By Title
Sivapithecus, fossil primate genus dating from the Miocene Epoch (23.7 to 5.3 million years ago) and thought to......
Smilodon, extinct genus of large mammalian carnivores known collectively by the common name sabre-toothed cat.......
Solo man, prehistoric human known from 11 fossil skulls (without facial skeletons) and 2 leg-bone fragments that......
Spalacotherium, extinct genus of primitive, probably predaceous, mammals known from fossils found in European deposits......
Spinosaurus, genus of theropod dinosaurs belonging to the family Spinosauridae, known from incomplete North African......
spiny shark, any of a group of more than 150 species of small extinct fishes traditionally classified in the class......
stegosaur, any of the plated dinosaur species, including Stegosaurus and Tuojiangosaurus of the Late Jurassic period......
Stegosaurus, (genus Stegosaurus), one of the various plated dinosaurs (Stegosauria) of the Late Jurassic Period......
Steneosaurus, (genus Steneosaurus), extinct crocodiles that inhabited shallow seas and whose fossils are found......
Nicolaus Steno was a geologist and anatomist whose early observations greatly advanced the development of geology.......
Streptelasma, extinct genus of corals, existing as single animals rather than colonial forms and found as fossils......
Stringocephalus, extinct genus of large brachiopods, or lamp shells, found as fossils in Devonian marine rocks......
Stromatoporida, extinct order of corals found as fossils in marine rocks of Cambrian to Cretaceous age (542 million......
Stropheodonta, genus of small, extinct brachiopods (lamp shells) found as fossils in Devonian marine rocks (those......
Strophomena, genus of extinct brachiopods (lamp shells) found as fossils in Middle and Upper Ordovician marine......
Struthiomimus, (genus Struthiomimus), ostrichlike dinosaurs found as fossils from the Late Cretaceous Period (99......
Sturtian Series, division of Proterozoic rocks in south central Australia (the Proterozoic Eon lasted from 2.5......
Sue, nickname for one of the most complete and best-preserved skeletons of Tyrannosaurus rex. The fossil was dated......
law of superposition, a major principle of stratigraphy stating that within a sequence of layers of sedimentary......
Although his formal education occurred between the ages of 8 and 10, plus four or five years at medical school,......
Tabulata, major division of extinct coral animals found as fossils in Ordovician to Jurassic marine rocks (488......
Tabūn, site of paleoanthropological excavations in a deep rock shelter located on the edge of Mount Carmel and......
taeniodont, any member of an extinct suborder (Taeniodonta) of mammals that lived in North America throughout the......
Tapinocephalus, extinct genus of therapsids, relatives of mammals, found as fossils in Permian rocks of South Africa......
Taung child, the first discovered fossil of Australopithecus africanus. Exhumed by miners in South Africa in 1924,......
Pierre Teilhard de Chardin was a French philosopher and paleontologist known for his theory that man is evolving,......
tephrochronology, method of age determination that makes use of layers of ash (tephra). Tephra layers are excellent......
Henri-François-Émile Termier was a French geologist known for his studies of the stratigraphy (study of stratified......
Tertiary Period, former official interval of geologic time lasting from approximately 66 million to 2.6 million......
Tetractinella, genus of extinct brachiopods (lamp shells) found as fossils in Triassic marine rocks (the Triassic......
Tetragraptus, genus of extinct graptolites (colonial animals related to the chordates) that occur as fossils in......
Abraham Lincoln and Charles Darwin, two of the 19th century’s most enduring thinkers and figures, share more than......
thecodontian, archaic term formerly applied to any member of a group of primitive archosaurs (“ruling reptiles”)......
Theodossia, genus of extinct brachiopods (lamp shells) the fossils of which are restricted to Early Devonian marine......
therapsid, any member of the Therapsida, a major clade of tetrapods that lived during Permian and Triassic time......
therizinosaur, group of theropod dinosaurs that lived during the Late Cretaceous (roughly 100 million to 66 million......
theropod, any member of the dinosaur subgroup Theropoda, which includes all the flesh-eating dinosaurs. Theropods......
Thrinaxodon, extinct genus of cynodont, a close mammal relative, found as fossils in continental deposits formed......
Tiktaalik roseae, an extinct fishlike aquatic animal that lived about 380–385 million years ago (during the earliest......
Titanoboa, (Titanoboa cerrejonensis), extinct snake that lived during the Paleocene Epoch (66 million to 56 million......
titanosaur, (clade Titanosauria), diverse group of sauropod dinosaurs classified in the clade Titanosauria, which......
titanothere, any member of an extinct group of large-hoofed mammals that originated in Asia or North America during......
Tonian Period, earliest of the three periods of the Neoproterozoic Era, extending from 1 billion to approximately......
Tornoceras, extinct genus of cephalopods, forms related to the modern pearly nautilus. Tornoceras is a form that......
Tournaisian Stage, lowest and first of three intercontinental stages of the Mississippian Subsystem, Carboniferous......
Toxodon, extinct genus of mammals of the late Pliocene and the Pleistocene Epoch (about 3.6 million to 11,700 years......
Trepostomata, extinct order of bryozoans (moss animals) found as fossils in marine rocks of Ordovician to Triassic......
Triassic Period, in geologic time, the first period of the Mesozoic Era. It began 252 million years ago, at the......
Triceratops, (genus Triceratops), large quadrupedal plant-eating ceratopsian dinosaur that had a frill of bone......
Triconodon, genus of extinct mammals found in European deposits of the late Jurassic Period (about 161 million–146......
trilobite, any member of a group of extinct fossil arthropods easily recognized by their distinctive three-lobed,......
tritylodont, any member of a genus (Tritylodon) of extinct cynodont therapsids (mammal relatives) found as fossils......
Trochonema, genus of extinct gastropods (snails) found as fossils in rocks dating from the Ordovician Period to......
Tropidoleptus, genus of extinct brachiopods (lamp shells) found as fossils only in marine rocks of the Devonian......
Tropites, genus of extinct cephalopods (animals similar to the modern squid and octopus but with an external shell)......
tyrannosaur, any of a group of predatory dinosaurs that lived from the late Jurassic Period (about 150 million......
Tyrannosaurus rex, (Tyrannosaurus rex), species of predatory dinosaurs that lived during the end of the Cretaceous......
Uintatherium, extinct genus of large, hoofed mammals found as fossils in North America and Asia in terrestrial......
uranium-234–uranium-238 dating, method of age determination that makes use of the radioactive decay of uranium-238......
uranium-thorium-lead dating, method of establishing the time of origin of a rock by means of the amount of common......
Velociraptor, (genus Velociraptor), sickle-clawed dinosaur that flourished in central and eastern Asia during the......
Venyukovia, genus of extinct mammallike reptiles (therapsids) that are found as fossils in Permian deposits in......
Vindija, site of paleoanthropological excavations in the Hrvatsko Zagorje region of Croatia, known for Neanderthal......
Viséan Stage, second of three internationally defined stages of the Mississippian Subsystem of the Carboniferous......
Voltzia, a genus of fossil cone-bearing plants dating to the Early Triassic epoch (beginning 251 million years......
Wedekindellina, genus of fusulinid foraminiferans, an extinct group of protozoans that possessed a hard shell of......
William Crawford Williamson was an English naturalist and a founder of modern paleobotany. Apprenticed to an apothecary......
Witteberg series, uppermost member of the Cape System of sedimentary rocks in South Africa. It consists of about......
Witwatersrand System, major division of Precambrian rocks in South Africa (the Precambrian began about 3.8 billion......
woolly rhinoceros, (genus Coelodonta), either of two extinct species of rhinoceros found in fossil deposits of......
Wordian Stage, second of three stages of the Middle Permian (Guadalupian) Series, made up of all rocks deposited......
Worthenia, genus of extinct gastropods (snails) preserved as common fossils in rocks of Devonian to Triassic age......
Xenacanthus, long-surviving but now extinct genus of freshwater sharks. Xenacanthus survived from the end of the......
Yinlong, ceratopsian dinosaur genus known from a single nearly complete skeleton taken from the Junggar Basin of......
Karl Alfred, knight von Zittel was a paleontologist who proved that the Sahara had not been under water during......