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Gauja Formation
The Gauja Formation is a Middle Devonian fossil locality in Estonia and Latvia. It is named after the Gauja River, where it is exposed along the banks. Description The Gauja Formation has a maximum thickness of . It is composed of weakly to moderately cemented layers of fine-grained to very fine-grained sandstone. The layer is predominantly light to yellowish-gray in color, but can be pinkish brown or variegated. It is mostly composed of quartzose arenites. It is overlain by the thick Amata Formation and the Plavinas Formation. The Gauja Formation contains two cyclic members. The lower layers are known as the Sietin Member and are composed mostly of sandstone with a thin layer of siltstone at the top. It has yielded numerous fossils of fishes. Among them are '' Asterolepis'', ''Bothriolepis'', '' Glyptolepis baltica'', '' Laccognathus panderi'', '' Livoniana multidentata'',Ahlberg et al., 2000 and '' Megadonichthys kurikae''. The upper layers are thicker, and the lower par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gauja River
The Gauja River ( et, Koiva jõgi, german: Livländische Aa) is a river in the Vidzeme region of Latvia. It is the only large river of Latvia that begins and ends its flow in Latvia. Its length is 460 km, of which 93.5 km (approximately one-fifth) are in the Gauja National Park. In this part, the Gauja River flows through the Gauja valley, which is 1 to 2.5 km wide, and the maximum depth near Sigulda is 85 m. Thus, Gauja is the longest river of Latvia when we count only the parts of the river in the country's territory. Daugava has only 367 km in Latvia, while the whole river is over 1000 km. The sandstone rocks on the banks of the Gauja and its adjoining rivers started forming 370 to 300 million years ago during the Devonian period. History Before the 13th century, the Gauja River used to serve as a trade route and border river between the Livonian and Latgalian lands. In some territories, they used to live mixed together. When Livonian languages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bothriolepis
''Bothriolepis'' (from el, βόθρος , 'trench' and el, λεπίς 'scale') was a widespread, abundant and diverse genus of antiarch placoderms that lived during the Middle Devonian, Middle to Late Devonian period of the Paleozoic Era. Historically, ''Bothriolepis'' resided in an array of paleo-environments spread across every paleocontinent, including near shore marine and freshwater settings. Most species of ''Bothriolepis'' were characterized as relatively small, benthic, freshwater detritivores (organisms that obtain nutrients by consuming decomposing plant/animal material), averaging around in length. However, the largest species, ''B. rex'', had an estimated bodylength of . Although expansive with over 60 species found worldwide, comparatively ''Bothriolepis'' is not unusually more diverse than most modern bottom dwelling species around today. Classification ''Bothriolepis'' is a genus placed within the placoderm order Antiarchi. The earliest antiarch placoderms fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossil Sites
This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there. Many of the entries in this list are considered Lagerstätten (sedimentary deposits that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues). Lagerstätten are indicated by a note () in the noteworthiness column. Fossils may be found either associated with a geological formation or at a single geographic site. Geological formations consist of rock that was deposited during a specific period of time. They usually extend for large areas, and sometimes there are different important sites in which the same formation is exposed. Such sites may have separate entries if they are considered to be more notable than the formation as a whole. In contrast, extensive formations associated with large areas m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossiliferous Stratigraphic Units In Latvia
See also * Lists of fossiliferous stratigraphic units in Europe These lists of fossiliferous stratigraphic units in Europe enumerate the rock layers which preserve the fossilized remains of ancient life in Europe by the modern countries wherein they are found. Graphical atlas ... References * {{DEFAULTSORT:Fossiliferous stratigraphic units in Latvia Latvia Geology of Latvia Fossiliferous stratigraphic units Fossiliferous stratigraphic units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palynological
Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits including sediments of any age. The condition and identification of those particles, organic and inorganic, give the palynologist clues to the life, environment, and energetic conditions that produced them. The term is commonly used to refer to a subset of the discipline, which is defined as "the study of microscopic objects of macromolecular organic composition (i.e., compounds of carbon, hydrogen, nitrogen and oxygen), not capable of dissolution in hydrochloric or hydrofluoric acids". It is the science that studies contemporary and fossil palynomorphs (paleopalynology), including pollen, spores, orbicules, dinocysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter (POM) and kerogen found in sedimenta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancyrospora
''Ancyrospora'' is a fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ... plant genus. The genus was described in 1960 by J.B. Richardson. References Prehistoric plant genera Silurian plants Devonian plants Carboniferous plants Triassic plants {{triassic-plant-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeopteris
''Archaeopteris'' is an extinct genus of progymnosperm tree with fern-like leaves. A useful index fossil, this tree is found in strata dating from the Upper Devonian to Lower Carboniferous (), the oldest fossils being 385 million years old, and had global distribution. Until the 2007 discovery of '' Wattieza'', many scientists considered ''Archaeopteris'' to be the earliest known tree. Bearing buds, reinforced branch joints, and branched trunks similar to today's wood, it is more reminiscent of modern seed-bearing trees than other spore bearing taxa; It combines characteristics of woody trees and herbaceous ferns, and belongs to the progymnosperms, a group of extinct plants with gymnosperm-like wood but that produce spores rather than seeds. Taxonomy John William Dawson described the genus in 1871. The name derives from the ancient Greek (''archaīos'', "ancient"), and (''ptéris'', "fern"). ''Archaeopteris'' was originally classified as a fern, and it remained classif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hostinella
''Hostinella'' is a form genus, used for bare dichotomously branching stems (axes) which have not been found in association with spore-forming organs or sporangia and so cannot be assigned to a more precise genus or species. Specimens assigned to this genus have been found in Bathurst Island, Canada, in the Bertie Formation of Upper Silurian age (around ), where the stems are approximately 1.2 mm in diameter; and in Lower Devonian Senni beds (from around ) where the axes have a straited external appearance and contain xylem with tracheids (diameter: 40 µm). It is known to co-occur with ''Krithodeophyton ''Krithodeophyton'' is a genus of lower Devonian plant with branching axes. It is considered to be a barinophyte. Phylogeny The phylogenetic position of the barinophytes remains disputed. Kenrick and Crane in 1997 called the group the Barinophy ...''. References Silurian plants Early Devonian plants Prehistoric plant genera Silurian first appearances E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miospore
Cryptospores are fossilised primitive plant spores that first appear in the fossil record during the middle of the Ordovician period. Evidence that cryptospores derive from land plants Occurrence Cryptospores are generally found in non-marine rocks and decrease in abundance with distance offshore. This suggests that any cryptospores found in the marine environment were transported there by the wind from the land, rather than originating from the marine environment. Wall ultrastructure The walls of cryptospores consist of many lamellae (thin sheets). Liverworts, thought to be the most primitive land plants, also have this spore wall morphology. Chemical composition (Some) cryptospores are composed of sporopollenin and have the same chemical makeup as co-occurring trilete spores. Other information Recently, fossils of plant sporangia have been found in Oman with cryptospores showing concentric lamellae in their walls, similar to liverworts. The earliest known cryptospores are fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megadonichthys Kurikae
''Megadonichthys kurikae'' is an extinct species of fish belonging to the family Osteolepididae Osteolepididae is an family of primitive, fish-like tetrapodomorphs (the clade that contains modern tetrapods and their extinct relatives) that lived during the Devonian period. The family is generally thought to be paraphyletic, with the trai .... It is found in Estonia. References Tetrapodomorphs Prehistoric lobe-finned fish genera Middle Devonian sarcopterygians Devonian sarcopterygians of Europe Fossil taxa described in 2004 {{Paleo-tetrapodomorph-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
