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Paleontology in Maryland refers to paleontological research occurring within or conducted by people from the U.S. state of Maryland. The invertebrate fossils of Maryland are similar to those of neighboring Delaware.〔 For most of the early Paleozoic era, Maryland was covered by a shallow sea, although it was above sea level for portions of the Ordovician and Devonian. The ancient marine life of Maryland included brachiopods and bryozoans while horsetails and scale trees grew on land. By the end of the era, the sea had left the state completely. In the early Mesozoic, Pangaea was splitting up. The same geologic forces that divided the supercontinent formed massive lakes. Dinosaur footprints were preserved along their shores. During the Cretaceous, the state was home to dinosaurs. During the early part of the Cenozoic era, the state was alternatingly submerged by sea water or exposed. During the Ice Age, mastodons lived in the state. Local Delaware people told myths about a creature called the "Grandfather of the Monsters" and Little People that may have been inspired by local dinosaur footprints. By the 1850s, formal scientific investigation of the local fossils had commenced. Early discoveries included ''Astrodon'', the first scientifically described sauropod from North America. Maryland was home to one of the most significant Pleistocene mammal discoveries in American history: the early 20th century discovery of Pleistocene fossils in an Allegany County cave. The Miocene murex snail ''Ecphora gardnerae gardnerae'' is the Maryland state fossil. ''Astrodon johnstoni'' is the state dinosaur of Maryland. ==Prehistory== No Precambrian fossils are known from Maryland. As such, the state's fossil record does not begin until the Paleozoic. Maryland was covered by a warm shallow sea during the Cambrian and Ordovician periods. Geologic forces elevated the state above sea level late in the latter period, although the seas later returned. During the Devonian another period of uplift raised the state out of the sea, before erosion and subsidence brought it back under. One final episode of uplift during the Paleozoic occurred at the boundary between the Carboniferous and Permian. Maryland was home to creatures like brachiopods and bryozoans during periods where the state was under seawater. While the sea was absent, horsetails and scale trees grew across the state. Maryland was hot and humid during the late Paleozoic. By the end of the era the state was almost entirely a terrestrial environment.〔 During the Mesozoic powerful geologic forces were splitting the supercontinent of Pangaea. These same forces formed rifts in Maryland. Lakes and river formed in these rifts. Elements of the local flora would end up fossilized in sediments deposited by these same bodies of water.〔 The only known dinosaur footprints in Maryland were laid down during the Late Triassic on sediments that later became the Gettysburg Formation north of Emmitsburg in Frederick County.〔 For a 30 million year interval spanning the Late Triassic-Early Jurassic boundary, the Culpeper Basin was an extensive lake.〔 Sea levels fluctuated during the ensuing Cretaceous period. Sometimes Maryland was subemerged under the sea and sometimes it was exposed as dry land. Contemporary marine life included brachiopods and molluscs.〔 Maryland and Washington, D.C. are the only places where Early Cretaceous dinosaur remains are known to have been preserved east of the Mississippi River.〔 The only known Late Cretaceous dinosaur fossils discovered in Maryland were found in the Severn Formation of Prince George's County east of Washington, D.C.〔 During the ensuing Tertiary period of the Cenozoic era, sea levels also varied substantially.〔 During the Paleocene Maryland was home to at least 10 different kinds of ostracods.〔 During the Miocene, Maryland was home to the sea turtle ''Bothremys'', which may have fed by crushing snails.〔 Glaciers never reached Maryland during the later Ice Age. However, they still had an impact on the local environment as when water was trapped frozen in glaciers it caused the local sea levels to drop. The local climate was cold and the local flora correspondingly different. The local wildlife was also different and included such animals as mastodons. During warmer periods the glaciers would melt and sea levels rise. Clams, oysters, and snails lived in these higher waters and were preserved in the eastern part of the state.〔 On land, Pleistocene Maryland was home to a great diversity of mammals.〔 During the middle of that epoch, Maryland was covered in a moist woodland habitat.〔 Around this time a cavity in the limestone composing an Allegany County hill served as a death trap for many unwary animals over an extended period. Among the preserved remains were animals from very warm, intermediate and very cold climates, documenting the changes in the make up of the local wildlife in response to the planet's changing climate.〔 The mammals typifying the warm "southern" fauna included some of the bats, peccaries, and a tapir. A crocodile added a reptilian element to this "southern" fauna. The intermediate latitude-type fauna was characterized by a badger, a variety of bears, deer, a mastodon, otter, and a puma-like animal. The mammals more typical of northern habitats included elk, a fisher, hare, lemming, mink, jumping mouse, muskrat, pika, porcupine, long tailed shrew, red squirrel, and wolverine.〔 Large animals are conspicuously absent from the deposit and few of the fossils suggest anything larger than a modern black bear. Also conspicuous is the absence of many kinds of animal that are common in the Pleistocene deposits in the United States like bison, camels, giant ground sloths, musk oxen relatives of modern elephants, and saber teeth.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Paleontology in Maryland」の詳細全文を読む スポンサード リンク
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