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Toad Formation
Toad Formation, Grayling Formation, and Toad-Grayling Formation are obsolete names for the strata of the Early to Middle Triassic Doig and Montney Formations. They were applied in the foothills and Rocky Mountains of northeastern British Columbia, on the western edge of the Western Canada Sedimentary Basin. Although the names are considered obsolete, their usage persists. The Toad and Grayling strata have yielded fossils of marine organisms, including ammonites, brachiopods, and bivalves. Stratigraphic history The Toad and Grayling Formations were originally described by E.D. Kindle in 1944,Kindle, E.D. 1944. Geological reconnaissance along Fort Nelson, Liard and Beaver rivers, northeastern British Columbia and southeastern Yukon. Geological Survey of Canada, Paper 44-16, 16 p. who named them for the Toad and Grayling Rivers, which are tributaries of the Liard River in northeasternmost British Columbia. They were combined as the Toad-Grayling Formation by A.D. Hunt and J.D. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludington Formation
The Schooler Creek Group is a stratigraphic unit of Middle to Late Triassic ( Ladinian to Norian) age in the Western Canadian Sedimentary Basin. It is present in northeastern British Columbia. It was named for Schooler Creek, a left tributary of Williston Lake, and was first described in two oil wells (Pacific Fort St. John No. 16 and Southern Production No. B-14-1) northwest of Fort St. John, by F.H. McLearn in 1921.McLearn, F.H., 1921. Mesozoic of upper Peace River, British Columbia Geological Survey of Canada, Summary Report 1920, Part B, p. 1-6. Exposures along Williston Lake serve as a type locality in outcrop. Lithology The Schooler Creek Group is composed of limestone and dolomite, with subordinate siltstone, shale, sandstone, and evaporite minerals such as gypsum and anhydrite. Distribution The Schooler Creek Group outcrops in the foothills of the northern Canadian Rockies in northeastern British Columbia, where it reaches its maximum thickness of . In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
