Gastropod fossil in limestone (Mill Knob Member, Slade Formation, Upper Mississippian; Clack Mountain Road Outcrop, south of Morehead, Kentucky, USA) : 無料・フリー素材/写真
Gastropod fossil in limestone (Mill Knob Member, Slade Formation, Upper Mississippian; Clack Mountain Road Outcrop, south of Morehead, Kentucky, USA) / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Gastropod fossil in the Mississippian of Kentucky, USA.This fossiliferous rock is from the Upper Mississippian Slade Formation in Kentucky. The unit was formerly known as the Newman Limestone ("They always change the names to protect the innocent!"). Slade Formation limestones are shallow ocean deposits. The section shown here has numerous paleosol horizons (= ancient soils).Of all the molluscs, the gastropods (snails) have made the most ecological adaptations. They can be found in almost all fundamental environments: marine, freshwater, terrestrial. Most gastropods live in the ocean, and have a single, asymmetrically coiled, external shell of calcium carbonate (CaCO3 - usually aragonite). The hard calcareous shell is the most easily fossilized part of the gastropod. The soft parts of a snail (the “slug” portion) include a well developed head having eyes, tentacles, and a mouth, and a well developed, strong, muscular foot used principally for locomotion. The shell is carried upright on the snail’s back, or is partially dragged behind. When threatened by a predator, many snails can retract their soft parts into the shell’s interior for protection. Most marine snails are herbivores (algae grazers) or predators/carnivores. Many fossil snails in the Paleozoic rock record are often not well preserved, or are preserved as internal molds. The original aragonite of many gastropod shells is not stable on geologic time scales, and often recrystallizes or dissolves completely away. Fossil snail shells in Mesozoic and Cenozoic rocks are usually better preserved.Classification: Animalia, Mollusca, GastropodaStratigraphy: Mill Knob Member, Slade Formation, Upper MississippianLocality: roadcut next to the Clack Mountain Road-Route 519 intersection, south of Morehead, Kentucky, USA (vicinity of 38° 07’ 41.87” North latitude, 83° 24’ 47.04” West longitude) |
| 撮影日 | 2018-03-11 13:05:57 |
| 撮影者 | James St. John |
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