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a trayful of ornaments seen on a second-hand book stall and photographed rather quickly, I didn't get the frame straight, never mind. I don't know why my heart beats faster when I see things like this.
Cliché réalisé durant l'ascension de la Petite Aiguille Verte (3512m) dans le Massif du Mont Blanc (Haute-Savoie).
Cycadella sp. - fossil cycad from the Jurassic of Wyoming, USA. (UW 24032, University of Wyoming Geological Museum, Laramie, Wyoming, USA)
Plants are multicellular, photosynthetic eucaryotes. The oldest known land plant body fossils are Silurian in age. Fossil root traces of land plants are known back in the Ordovician. The Devonian was the key time interval during which land plants flourished and Earth experienced its first “greening” of the land. The earliest land plants were small and simple and probably remained close to bodies of water. By the Late Devonian, land plants had evolved large, tree-sized bodies and the first-ever forests appeared.
Seen here is a fossil cycad, a group of seed plants. Cycads were relatively common during the Mesozoic Era, when dinosaurs existed. The first cycad fossils are Pennsylvanian to Permian in age. Modern cycads include 11 genera and between 150 and 200 species. They are fairly geographically restricted today, but were more cosmopolitan in the geologic past.
The fossil's preservation style is quartz permineralization, which refers to the porosity of wood or bone being filled by minerals as groundwater percolates through after burial. The most common permineralization mineral is quartz (SiO2), but many other minerals have been reported as well.
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From exhibit signage:
CYCAD
Petrified tropical "tree" trunks
Geographic Range: Most notable finds have been in Wyoming and South Dakota.
Size: Some cycads (such as these) were no bigger than modern palmettos; others grew up to 9 feet (2.5 meters) high.
Habitat: Hot, humid tropics, along riverbanks, or in swamps.
Species: These specimens belong to the genus Cycadella. Over 23 different cycad species have been identified in Wyoming.
How these trees became fossils: After dying and being buried under sediment, these stems (trunks) became fossilized through a process of mineral substitution known as silicification. Water flowing under ground slowly replaced the tree's original mineral organic matter with silica to create a rock-hard fossil, maintaining the plant's original shape. These fossils are often compressed, sheared, and twisted by the pressure of the weight on top of them and also by tectonic forces.
Cycads are characterized by a large central pith covered with a thin woody zone and a hard, pineapple-like "bark".
These fossils were collected from the Freezeout Hills in Carbon County, Wyoming. The specimens have been in the museum's possession since 1899 and are noted in G.R. Wieland's landmark text entitled "American Fossil Cycads".
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Classification: Plantae, Cycadophyta, Cycadopsida, Cycadales
Stratigraphy: Cycad Bed, Morrison Formation, Upper Jurassic
Locality: unrecorded / undisclosed site in the Freezeout Hills, Carbon County, southern Wyoming, USA
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Info. at:
Weird traces of people that get left behind that you never even think about. Canon EOS R6 with Laowa 45mm f0.95