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Some of the most unusual concretion nuclei are World War II military shells, bombs, and shrapnel, which are found inside siderite concretions found in an English coastal salt marsh. [ 10 ] Depending on the environmental conditions present at the time of their formation, concretions can be created by either concentric or pervasive growth.
One common example is when manganese oxides crystallize with a characteristic tree-like or dendritic pattern along a rock fracture. The formation of frost dendrites on a window is another common example of this crystal growth. Concretions are sometimes thought to be fossils, and occasionally one contains a fossil, but are generally not fossils ...
A coal ball is a type of concretion, varying in shape from an imperfect sphere to a flat-lying, irregular slab.Coal balls were formed in Carboniferous Period swamps and mires, when peat was prevented from being turned into coal by the high amount of calcite surrounding the peat; the calcite caused it to be turned into stone instead.
Cyathus striatus, commonly known as the fluted bird's nest, [5] [6] is a common saprobic bird's nest fungus with a widespread distribution throughout temperate regions of the world. This fungus resembles a miniature bird's nest with numerous tiny "eggs"; the eggs, or peridioles , are actually lens-shaped bodies that contain spores .
A well-preserved marine fossil site in the Zagros Mountains with thousands of known fish fossils, as well as plants, crustaceans, insects, and birds. [178] Iraniplectus, an unusual tetraodontiform: Canyon Ferry Reservoir 32.0 ± 0.1 Ma Montana, US A diverse Early Oligocene plant and insect fossil site. [179] Luberon (Campagne-Calavon Formation ...
The dark horizontal lines on silver birch bark are the lenticels. [1]A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of gymnosperms and dicotyledonous flowering plants. [2]
The discovery of the Casparian strip dates back to the mid-19th century, and advances in the understanding of the endodermis of plant roots. [15] In 1865, the German botanist Robert Caspary first described the endodermis of the root of plants, found that its cell wall was thickened, and named it Schuchtzscheide.
The fossil history of flowering plants records the development of flowers and other distinctive structures of the angiosperms, now the dominant group of plants on land.The history is controversial as flowering plants appear in great diversity in the Cretaceous, with scanty and debatable records before that, creating a puzzle for evolutionary biologists that Charles Darwin named an "abominable ...