| Mehrten Formation | |
|---|---|
| Stratigraphic range: Neogene | |
| Type | Formation |
| Location | |
| Region | California |
| Country | United States |
The Mehrten Formation is a geologic formation in California that is a type of Inverted Relief that was principally formed of andesitic clastic and pyroclastic material that came from volcanos and filled rivers and valleys. Then that rock resist erosion better than the land around it leaving ridges that look like inverted rivers meanders.
It was originally described in the 1939 Geology and Ground-Water Hydrology of the Mokelumne Area, California, Piper et. al.
Naturalist John Muir described them as "dead rivers" in his writings. Also known as Inverted Relief.
The Eagle Sandstone, originally the Eagle Formation, is a geological formation in Montana whose strata date back to the Late Cretaceous. It is a light to brownish gray to pale yellow-orange, fine-grained sandstone. It contains areas of crossbedding and local shale members. It contains large sandy calcareous concretions. Its thickness varies from 100 to 350 feet due to the lens nature of the individual sandstone layers and local interbedded sandy shale layers.
Ochotona spanglei is an extinct species of pika, known from Late Miocene - Early Pliocene fossil from Oregon (USA). Fossils were also found in Nebraska referred to as Ochotona cf. spanglei.
The Waynesburg Formation is a coal, sandstone, and siltstone geologic formation in West Virginia and Pennsylvania. It preserves fossils dating back to the Permian period.
The Weches Formation is a greensand, slay, and shale geologic formation in Louisiana and Eastern Texas. It preserves fossils dating back to the Paleogene period, specifically the Eocene.
The Belle Fourche Formation or Belle Fourche Shale is a fossiliferous early Late-Cretaceous geologic formation classification in Wyoming. Named for outcrops in Belle Fourche River, Wyoming, this unit name is also used in Montana, North Dakota, and South Dakota.
The Wind River Formation is a geologic formation in Wyoming in the Wind River Basin. It preserves fossils dating back to the Paleogene period. A recent study by Stanford suggests that fracking has contaminated the entire ground water resource in the basin.
The Colton Formation is a geologic formation in Utah. Its age is based on its position between the Upper Cretaceous-Paleocene North Horn Formation and overlying Green River Formation.
The Merced Formation is a geologic formation in California, and also in Oregon and Washington state. It is named for Lake Merced, a natural lake on the western San Francisco coastline. The California portion is composed of a variety of sediments deposited on the coast of the San Francisco Bay Area in a small basin, which was split into two halves by the San Andreas Fault.
The Moraga Formation, also known as the Moraga Volcanics, is a geological formation that dates back to the Pliocene epoch. It is located in Berkeley Hills, East Bay Region, San Francisco Bay Area, California.
The Orinda Formation is a Miocene epoch geologic formation in the Berkeley Hills of the East Bay region of the San Francisco Bay Area, California.
The Kern River Beds Formation is a Neogene Period geologic formation in the southeastern San Joaquin Valley, within Kern County, California.
The Etchegoin Formation is a Pliocene epoch geologic formation in the lower half of the San Joaquin Valley in central California.
The Chanac Formation is a Cenozoic Era sandstone geologic formation in the southeastern San Joaquin Valley, within Kern County, California.
The Tulare Formation is a Pliocene to Holocene epoch geologic formation in the central and southern San Joaquin Valley of central California.
The Friars Formation is a geologic formation in San Diego County, Southern California.
The Poway Group is a geologic group in San Diego County, Southern California. It preserves fossils dating back to the Paleogene period.
The Tejon Formation is a Paleogene period geologic formation in California.
The Montezuma Formation is a geologic formation in California, just north of the confluence of the Sacramento and San Joaquin Rivers. The formation contains early Pleistocene deposits consisting of "poorly sorted, poorly consolidated clayey sand, silt, and pebble gravel." It is ranked "high" in "Potential Sensitivity for Paleontological Resources."
The San Benito Gravels is a Quaternary Epoch geologic formation in California.
The Turlock Lake Formation is an Early Pleistocene geologic formation in the Sierra Nevada foothills in Sacramento County, California. Cities in/over the formation's area include Citrus Heights, Carmichael, and Roseville.
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