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Johnson Formation
The Johnson Formation (or Johnson Limestone) is a thick Formation (geology), geologic formation of soft shale with thin, resistant beds of chalkier mudstone and limestone in Nebraska, Kansas, and Oklahoma rarely exposed outside of road cuts. It preserves fossils dating back to the late-Carboniferous Period (geology), period. See also * List of fossiliferous stratigraphic units in Kansas * List of fossiliferous stratigraphic units in Nebraska * List of fossiliferous stratigraphic units in Oklahoma * Paleontology in Kansas * Paleontology in Nebraska * Paleontology in Oklahoma References Carboniferous Oklahoma Carboniferous Kansas Carboniferous geology of Nebraska Carboniferous southern paleotropical deposits Shale formations of the United States Mudstone formations of the United Kingdom Limestone formations of the United States Geologic formations of Oklahoma Geologic formations of Kansas Geologic formations of Nebraska {{Carboniferous-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head Cut (stream Geomorphology)
In geomorphology, a stream head cut or simply head cut (alternately headcut) is an erosional feature of some intermittent and perennial streams. Headcuts and headward erosion are hallmarks of unstable expanding drainage features such as actively eroding gullies. Headcuts are a type of knickpoint that, as the name indicates, occur at the head (upstream extent) of a channel. The knickpoint, where a head cut begins, can be as small as an overly-steep riffle zone or as a large as a waterfall. When it is not flowing, the head cut will resemble a very short cliff or bluff. A small plunge pool A plunge pool (or plunge basin or waterfall lake) is a deep depression in a stream bed at the base of a waterfall or Shut-in (river), shut-in. It is created by the erosion, erosional forces of cascading water on the rocks at the formation's bas ... may be present at the base of the head cut due to the high energy of falling water. As erosion of the knickpoint and the streambed continu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |