Fossils & Geologic Time, CAV-ELE
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
cave bear, either of two extinct bear species, Ursus spelaeus and U. deningeri, notable for their habit of inhabiting......
Cedaria, genus of trilobites (extinct arthropods) that is a useful index fossil for Cambrian rocks and time (about......
Cenozoic Era, third of the major eras of Earth’s history, beginning about 66 million years ago and extending to......
Cephalaspis, extinct genus of very primitive, jawless, fishlike vertebrates found in Lower Devonian rocks (the......
Ceratites, extinct genus of cephalopods (whose modern members include the octopus, the squid, and the nautilus)......
ceratopsian, any of a group of plant-eating dinosaurs from the Cretaceous Period (146 million to 66 million years......
Ceratosaurus, (genus Ceratosaurus), large carnivorous dinosaurs whose fossils date from the Late Jurassic Period......
Ceraurus, genus of trilobites (extinct arthropods) found as fossils in rocks of Ordovician period (505 to 438 million......
Chalicotherium, genus of extinct perissodactyls, the order including the horse and rhinoceros. Fossil remains of......
Cheirolepis, extinct genus of primitive fishes whose fossils are found in European and North American rocks of......
Chengjiang fossil site, formation in China containing fossils dating to the Terreneuvian Epoch of the Cambrian......
Chondrosteiformes, an extinct order of ray-finned saltwater fishes (class Actinopterygii) comprising a single family......
Chonetes, genus of extinct brachiopods, or lamp shells, found as fossils in marine rocks of Silurian to Permian......
Cladoselache, genus of extinct sharks, known from fossilized remains in Upper Devonian rocks (formed 385–359 million......
Clidastes, (genus Clidastes), extinct ancient marine lizards belonging to a family of reptiles called mosasaurs.......
Climacograptus, genus of graptolites, extinct colonial animals related to the primitive chordates, found as fossils......
Climatius, genus of extinct, primitive jawed vertebrates common as fossils in Devonian rocks in Europe and North......
Clonograptus, genus of graptolites (extinct, small floating colonial animals related to the primitive chordates),......
coal ball, a lump of petrified plant matter, frequently spheroid, found in coal seams of the Upper Carboniferous......
Coal Measures, major division of Upper Carboniferous rocks and time in Great Britain (the Upper Carboniferous Period......
coccolith, minute calcium carbonate platelet or ring secreted by certain organisms (coccolithophores, classed either......
Coelophysis, (genus Coelophysis), small carnivorous dinosaurs found as fossils from the Late Triassic Period (228......
Composita, genus of extinct brachiopods, or lamp shells, found as fossils in marine rocks of the Carboniferous......
Compsognathus, (genus Compsognathus), very small predaceous dinosaurs that lived in Europe during the Late Jurassic......
Conchidium, genus of extinct brachiopods, or lamp shells, that is a valuable index fossil in marine rocks of the......
Condylarthra, extinct group of mammals that includes the ancestral forms of later, more-advanced ungulates (hoofed......
Confuciusornis, genus of extinct crow-sized birds that lived during the Late Jurassic and Early Cretaceous (roughly......
conodont, minute toothlike fossil composed of the mineral apatite (calcium phosphate); conodonts are among the......
Constellaria, genus of extinct bryozoans (small colonial animals that produce a skeletal framework of calcium carbonate)......
William Daniel Conybeare was an English geologist and paleontologist, known for his classic work on the stratigraphy......
Edward Drinker Cope was a paleontologist who discovered approximately a thousand species of extinct vertebrates......
coprolite, the fossilized excrement of animals. The English geologist William Buckland coined the term in 1835......
Cordaitales, an order of coniferophytes (phylum, sometimes division, Coniferophyta), fossil plants dominant during......
Cordaites, extinct genus of seed plants with leathery, strap-shaped leaves from the Pennsylvanian Subperiod (318......
Coryphodon, genus of extinct primitive hoofed mammals known from Late Paleocene and Early Eocene deposits (those......
Coutchiching Series, division of rocks in the region of northern Minnesota and Ontario radiometrically dated to......
Creodonta, order of extinct carnivorous mammals first found as fossils in North American deposits of the Paleocene......
Crepicephalus, genus of trilobites (extinct arthropods) useful as an index fossil for Upper Cambrian rocks in North......
Cretaceous Period, in geologic time, the last of the three periods of the Mesozoic Era. The Cretaceous began 145.0......
Cro-Magnon, population of early Homo sapiens dating from the Upper Paleolithic Period (c. 40,000 to c. 10,000 years......
Cryogenian Period, second of three periods of the Neoproterozoic Era of geologic time, extending from approximately......
Cryptoblastus, extinct genus of blastoids, a primitive group of echinoderms related to the modern sea lilies, found......
Cryptolithus, genus of trilobites (extinct arthropods) found as fossils in Europe and North America in the Ordovician......
Cryptostomata, order of bryozoans (small colonial animals) found as fossils in rocks of Ordovician to Permian age......
Joseph Augustine Cushman was a U.S. paleontologist known for his work on paleoecology as shown by Foraminifera......
Georges Cuvier was a French zoologist and statesman, who established the sciences of comparative anatomy and paleontology.......
Cyathocrinites, extinct genus of crinoids, or sea lilies, found as fossils in Silurian to Permian marine rocks......
Cycadeoidea, a genus of extinct seed plants that was common worldwide during the Early Cretaceous Epoch (145 million......
Cycadeoidophyta, an extinct division of plants with certain features in common with cycads (division Pinophyta)......
Cynognathus, genus of extinct advanced therapsids (mammals and their relatives) found as fossils in Lower Triassic......
Cystiphyllum, extinct genus of solitary corals found as fossils in Silurian and Devonian marine rocks (the Silurian......
cystoid, any member of an extinct class (Cystoidea) of primitive echinoderms (animals with a hard, calcareous external......
Dalradian Series, sequence of highly folded and metamorphosed sedimentary and volcanic rocks of late Precambrian......
Daonella, genus of extinct pelecypods (clams) useful as a guide, or index, fossil in Triassic rocks. The shell......
Charles Darwin was an English naturalist whose scientific theory of evolution by natural selection became the foundation......
dating, in geology, determining a chronology or calendar of events in the history of Earth, using to a large degree......
- Introduction
- Geochronology, Tectonic Rock, Cycle
- Sequence, Stratigraphy, Radiometric
- Correlation, Stratigraphy, Radiometric
- Geochronology, Geologic Column, Time Scale
- Isotopic, Geochronology, Principles
- Evaluation, Presentation, Schemes
- Isochron, Geochronology, Radiometric
- Model Ages, Geochronology, Radiometric
- Instruments, Procedures, Geochronology
- Isotopic, Geochronology, Methods
- Zircon, Uranium-Lead, Geochronology
- Rubidium-Strontium, Geochronology, Method
- Metamorphic Rocks, Geochronology, Age Estimation
- Rhenium-Osmium, Geochronology, Method
- Fission Track, Geochronology, Radioactive Decay
- Carbon-14, Cosmogenic, Geochronology
- Uranium Series, Disequilibrium, Geochronology
Louis-Jean-Marie Daubenton was a French naturalist who was a pioneer in the fields of comparative anatomy and paleontology.......
Thomas Davidson was a Scottish naturalist and paleontologist who became known as an authority on lamp shells, a......
Margaret Bryan Davis is an American paleoecologist best known for her pioneering work in the science of palynology......
Sir John William Dawson was a Canadian geologist who made numerous contributions to paleobotany and extended the......
Gerhard, Baron De Geer was a Swedish geologist, originator of the varve-counting method used in geochronology.......
Deinonychus, (genus Deinonychus), long-clawed carnivorous dinosaurs that flourished in western North America during......
Deiphon, genus of trilobites (extinct arthropods) easily recognized in fossil form in Silurian rocks in North America......
Deltatheridium, a genus of extinct mammals found as fossils in rocks from Upper Cretaceous times (about 100–65.5......
Denisova Cave, site of paleoanthropological excavations in the Anui River valley roughly 60 miles (100 km) south......
Denisovan, member of a group of archaic humans who emerged about 370,000 years ago during the Pleistocene Epoch......
denticle, part of a conodont, a small toothlike fossil found in marine rocks representative of a long span of geologic......
Devonian Period, in geologic time, an interval of the Paleozoic Era that follows the Silurian Period and precedes......
Diadectes, extinct genus of tetrapods closely related to the first amniotes (mammals, birds, reptiles, and their......
Diarthrognathus, genus of extinct, advanced mammal-like reptiles found as fossils in Early Jurassic terrestrial......
Dictyoclostus, genus of extinct brachiopods, or lamp shells, that were common invertebrate forms in the shallow......
Didymograptus, genus of graptolites (an extinct group of colonial animals related to primitive chordates) found......
Dielasma, genus of extinct brachiopods, or lamp shells, that occur as fossils in rocks deposited in marine environments......
Dikelocephalus, genus of trilobites (extinct arthropods) that is a useful guide fossil for the Late Cambrian rocks......
Dilong, (Dilong paradoxus), genus of small feathered theropod dinosaurs known from rock deposits of the Yixian......
Dimetrodon, (genus Dimetrodon), extinct relative of primitive mammals that is characterized by a large, upright,......
Dimorphodon, (genus Dimorphodon), primitive flying reptiles found as fossils in European deposits from the Early......
Dinichthys, extinct genus of arthrodires, i.e., primitive, armoured, fishlike animals known as placoderms that......
dinosaur, (clade Dinosauria), the common name given to a group of reptiles, often very large, that first appeared......
- Introduction
- Evolution, Classification, Extinction
- Archosaurs, Reptiles, Triassic
- Extinction Causes, Evidence, & Theory
- Asteroid Theory, Extinction, Fossils
- Extinction, Fossils, Evolution
- Herding, Socialization, Adaptation
- Endothermic, Thermoregulation, Homeothermy
- Reptiles, Extinction, Fossils
- Sauropods, Herbivores, Quadrupeds
- Theropods, Extinction, Fossils
- Tetanurae, Reptiles, Extinction
- Ornithischia, Herbivore, Reptile
- Pachycephalosaurs, Head-Butting, Herbivores
- Armored, Herbivorous, Ornithischians
- Armored, Herbivorous, Extinct
Dinosaur National Monument, desert area in northwestern Colorado and northeastern Utah, U.S., set aside in 1915......
Dinosaur Provincial Park, public park located in the badlands of southeastern Alberta, Canada. The nearly 29-square-mile......
dinosauromorph, any of a group of archosaurian reptiles that includes dinosaurs and all other reptiles bearing......
Diplodocus, (genus Diplodocus), gigantic dinosaurs found in North America as fossils from the Late Jurassic Period......
Diplograptus, genus of graptolites, small, extinct colonial marine animals thought to be related to the primitive......
Diplovertebron, genus of extinct amphibians of North America and Europe known from fossils in Late Carboniferous......
Diprotodon, extinct genus of marsupial classified in the suborder Vombatiformes and considered to be the largest......
Dipterus, genus of very primitive lungfish, among the earliest known, found as fossils in European and North American......
dire wolf, (Aenocyon dirus), canine that existed during the Pleistocene Epoch (2.6 million to 11,700 years ago).......
Docodon, extinct genus of mammals originally known only from fossilized teeth. The dentition patterns of the cusps......
Dreadnoughtus, a genus of large sauropod dinosaurs, the largest land animal that ever lived. It had a total length......
dromaeosaur, (family Dromaeosauridae), any of a group of small to medium-sized carnivorous dinosaurs that flourished......
Dryopithecus, genus of extinct ape that is representative of early members of the lineage that includes humans......
Echinosphaerites, genus of cystoids, an extinct group related to the sea lily and starfish, found as fossils in......
Edaphosaurus, (genus Edaphosaurus), primitive herbivorous relative of mammals that is found in fossil deposits......
Ediacara fauna, unique assemblage of soft-bodied organisms preserved worldwide as fossil impressions in sandstone......
Ediacaran Period, uppermost division of the Proterozoic Eon of Precambrian time and latest of the three periods......
Christian Gottfried Ehrenberg was a German biologist, microscopist, scientific explorer, and a founder of micropaleontology—the......
Ehringsdorf remains, human fossils found between 1908 and 1925 near Weimar, Germany. The most complete fossils......
Loren Eiseley was an American anthropologist, educator, and author who wrote about anthropology for the lay person......
elephant bird, (family Aepyornithidae), any of several species of extinct giant flightless birds classified in......