Fossils & Geologic Time, LE -PAL
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
Le Moustier, paleoanthropological and archaeological site in the Dordogne region of southwestern France that has......
lead-210 dating, method of age determination that makes use of the ratio of the radioactive lead isotope lead-210......
Louis Leakey was a Kenyan archaeologist and anthropologist, a member of the distinguished Leakey family of scholars......
Lebachia, a genus of extinct cone-bearing plants known from fossils of the Late Carboniferous and Early Permian......
Joseph Leidy was a zoologist, one of the most distinguished and versatile scientists in the United States, who......
Lepidodendron, extinct genus of tree-sized lycopsid plants that lived during the Carboniferous Period (about 359......
Leptaena, genus of extinct brachiopods (lamp shells) commonly found as fossils in Ordovician to Lower Carboniferous......
Leptodesma, extinct genus of pelecypods (clams) found as fossils in Silurian to Lower Carboniferous rocks (between......
Leptodus, extinct genus of articulate brachiopods, or lamp shells, of the Permian Period (299 million to 251 million......
Leptolepis, genus of marine fishes very closely related to the first teleosts, the dominant group of fishes in......
Limnoscelis, extinct genus of tetrapod that appeared very close to the origin of amniotes (mammals, birds, or reptiles).......
Linoproductus, genus of extinct articulate brachiopods (lamp shells) found throughout the midcontinent region of......
Lipalian interval, in geology, time span suggested in an attempt to explain the sudden appearance of abundant life......
litoptern, (order Litopterna), any of various extinct hoofed mammals that first appeared in the Paleocene Epoch......
Lituites, genus of extinct cephalopods (primitive animals related to the modern pearly nautilus) found as fossils......
Llanocetus denticrenatus, one of the earliest known baleen whales, sole member of the family Llanocetidae, suborder......
Lluc, (Anoiapithecus brevirostris), nickname for the nearly complete upper and lower jaws and much of the associated......
William Lonsdale was an English geologist and paleontologist whose studies of fossil corals suggested the existence......
lophophore hypothesis, viewpoint that conodonts, small toothlike structures found as fossils in marine rocks over......
Lophophyllum, extinct genus of solitary marine corals found as fossils especially characteristic of the Late Carboniferous......
Lophospira, genus of extinct gastropods (snails) found as fossils in marine rocks of Ordovician to Devonian age......
Loxonema, genus of extinct gastropods (snails) found as fossils in rocks of Ordovician to Early Carboniferous age......
Lucy, nickname for a remarkably complete (40 percent intact) hominin skeleton found by American paleoanthropologist......
Ludfordian Stage, second of two stages of the Ludlow Series, made up of all rocks deposited during the Ludfordian......
Ludlow Series, the third of four main divisions (in ascending order) making up the Silurian System; it represents......
Lystrosaurus, extinct genus of about seven species of medium-sized heavily built animals that lived from the middle......
Maclurites, extinct genus of Ordovician gastropods (snails) found as fossils and useful for stratigraphic correlations......
Maiasaura, (genus Maiasaura), duck-billed dinosaurs (hadrosaurs) found as fossils from the Late Cretaceous Period......
mammoth, (genus Mammuthus), any member of an extinct group of elephants found as fossils in Pleistocene deposits......
Gideon Algernon Mantell was a British physician, geologist, and paleontologist, who discovered four of the five......
Marasuchus, genus of archosaurian reptiles that inhabited part of present-day South America during the Ladinian......
Othniel Charles Marsh was an American paleontologist who made extensive scientific explorations of the western......
mastodon, (genus Mammut), any of several extinct elephantine mammals (family Mammutidae, genus Mammut ) that first......
William Diller Matthew was a Canadian-American paleontologist who was an important contributor to modern knowledge......
Mauer, Pleistocene locality on the Neckar River of Germany and the name of a Pleistocene deposit, the Mauer Sands......
medieval warm period (MWP), brief climatic interval that is hypothesized to have occurred from approximately 900......
megalodon, (Carcharocles megalodon), member of an extinct species of megatooth shark (Otodontidae) that is considered......
Megalosaurus, (genus Megalosaurus), carnivorous dinosaur and the subject of the first scientific description of......
Megatherium, largest of the ground sloths, an extinct group of mammals belonging to a group containing sloths,......
Merychippus, extinct genus of early horses, found as fossils in deposits from the Middle and Late Miocene Epoch......
Mesohippus, genus of extinct early and middle Oligocene horses (the Oligocene Epoch occurred from 33.9 to 23 million......
Mesosaurus, (genus Mesosaurus), early aquatic relative of reptiles, found as fossils from the Early Permian Period......
Mesozoic Era, second of Earth’s three major geologic eras of Phanerozoic time. Its name is derived from the Greek......
Miacis, genus of extinct carnivores found as fossils in deposits of the late Paleocene Epoch (65.5–55.8 million......
Miocene Epoch, earliest major worldwide division of the Neogene Period (23 million years to 2.6 million years ago)......
Miohippus, genus of extinct horses that originated in North America during the Late Eocene Epoch (37.2–33.9 million......
Mississippian Subperiod, first major subdivision of the Carboniferous Period, lasting from 358.9 to 323.2 million......
Modiolopsis, extinct genus of pelecypods (clams) found as fossils in Ordovician rocks (about 488 million to 444......
Moeritherium, extinct genus of primitive mammals that represent a very early stage in the evolution of elephants.......
Monograptus, extinct genus of graptolites (small aquatic colonial animals related to primitive chordates) found......
Raymond Cecil Moore was an American paleontologist known for his work on Paleozoic crinoids, bryozoans, and corals......
Morganucodon, extinct genus of tiny mammals known from fossils dated to the Triassic-Jurassic boundary (approximately......
Moropus, extinct genus of the chalicotheres, a group of very unusual perissodactyls (“odd-toed” ungulates) related......
Morrison Formation, series of sedimentary rocks deposited during the Jurassic Period in western North America,......
mosasaur, (family Mosasauridae), extinct group of aquatic lizards that attained a high degree of adaptation to......
Moschops, extinct genus of mammal-like reptiles (Therapsida) found as fossils in rocks of Permian age (299 million......
Moscovian Stage, second of four internationally defined stages of the Pennsylvanian Subsystem of the Carboniferous......
Mucrospirifer, genus of extinct brachiopods (lamp shells) found as fossils in Middle and Upper Devonian marine......
multituberculate, any member of an extinct group of small, superficially rodentlike mammals that existed from about......
Mylodon, extinct genus of ground sloth found as fossils in South American deposits of the Pleistocene Epoch (2.6......
Myophoria, genus of extinct clams found as fossils in Triassic rocks. It is readily identified by its distinctive......
Sophus Otto Müller was a Danish archaeologist who, during the late 19th century, discovered the first of the Neolithic......
Neanderthal, (Homo neanderthalensis, Homo sapiens neanderthalensis), member of a group of archaic humans who emerged......
Neogene Period, the second of three divisions of the Cenozoic Era. The Neogene Period encompasses the interval......
neoprioniodiform, conodont, or small toothlike phosphatic fossil of uncertain affinity, that is characterized by......
Neospirifer, genus of extinct brachiopods (lamp shells) found as fossils in Late Carboniferous to Permian marine......
Nodosaurus, (genus Nodosaurus), armoured dinosaurs found as fossils in North America dating from 95 million to......
Notharctus, extinct genus of small primates (family Adapidae) that shares many similarities with modern lemurs,......
Nothosaurus, (genus Nothosaurus), marine reptiles found as fossils from the Triassic Period (251 million to 200......
Notoungulata, extinct group of hoofed mammals found as fossils, mostly in South America, although the oldest forms......
nummulite, any of the thousands of extinct species of relatively large, lens-shaped foraminifers (single-celled......
Obolus, genus of extinct brachiopod, or lamp shell, of the Cambrian Period (from 542 million to 488 million years......
obsidian–hydration–rind dating, method of age determination of obsidian (black volcanic glass) that makes use of......
odontolite, fossil bone or tooth that consists of the phosphate mineral apatite (q.v.) coloured blue by vivianite.......
Old Red Sandstone, thick sequence of Devonian rocks (formed from 416 million to 359.2 million years ago) that are......
Olenellus, genus of trilobites (extinct arthropods) common in but restricted to Early Cambrian rocks (542 million......
Oligocene Epoch, third and last major worldwide division of the Paleogene Period (65.5 million to 23 million years......
Onverwacht series, division of Archean rocks (the Archean Eon lasted from 3.96 to 2.5 billion years ago) in the......
Albert Oppel was a German geologist and paleontologist, who was one of the most important early stratigraphers.......
Alcide Dessalines d’ Orbigny was the founder of the science of micropaleontology. During eight years of travel......
Ordovician Period, in geologic time, the second period of the Paleozoic Era. It began 485.4 million years ago,......
oreodont, any member of a diverse group of extinct herbivorous North American artiodactyls (even-toed ungulates)......
Oreopithecus, extinct genus of primates found as fossils in Late Miocene deposits in East Africa and Early Pliocene......
ornithischian, any member of the large taxonomic group of herbivorous dinosaurs comprising Triceratops and all......
Ornitholestes, (genus Ornitholestes), small, lightly built carnivorous dinosaur found as fossils from the Late......
Ornithomimus, (genus Ornithomimus), ostrichlike feathered dinosaurs found as fossils in Mongolian, European, and......
ornithopod, any member of the group of ornithischian dinosaurs characterized by a two-legged (bipedal) stance,......
Henry Fairfield Osborn was an American paleontologist, eugenicist, and museum administrator who greatly influenced......
Osteolepis, extinct genus of lobe-finned fishes from the Late Devonian; Osteolepiformes is a variation of this......
John Ostrom was an American paleontologist who popularized the theory that many species of dinosaurs were warm-blooded......
Oviraptor, (genus Oviraptor), small, lightly built predatory or omnivorous dinosaur that brooded its eggs in a......
Richard Owen was a British anatomist and paleontologist who is remembered for his contributions to the study of......
ozarkodiniform, conodont, or small fossil that is toothlike in form and structure, that has a prominent, centrally......
Pachycephalosaurus, genus of large and unusual dinosaurs found as fossils in deposits of North America dating to......
Pachyrhinosaurus, genus of horned ceratopsid dinosaurs that roamed northwestern North America from 71 million to......
Pakicetus, extinct genus of early cetacean mammals known from fossils discovered in 48.5-million-year-old river......
Palaeospondylus, genus of enigmatic fossil vertebrates that were very fishlike in appearance but of uncertain relationships.......
paleoanthropology, interdisciplinary branch of anthropology concerned with the origins and development of early......
Paleocene Epoch, first major worldwide division of rocks and time of the Paleogene Period, spanning the interval......
Paleocene-Eocene Thermal Maximum (PETM), a short interval of maximum temperature lasting approximately 100,000......