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  • Separation and removal of rock material and formation of deposits, especially by wind action or the washing away of loose and soluble materials.
  • Age
    An interval of geologic time; a division of an epoch.
  • One that is actively depositing sediment in its channel or floodplain because it is being supplied with more load than it can transport.
  • One that has been at least partially filled with sand, silt, and mud by flowing water.
  • A general term for clay, silt, sand, gravel, or similar unconsolidated sorted or semi-sorted sediment deposited during comparatively recent time by a stream or other body of running water.
  • A convex upward rock fold in which strata have been bent into an arch; the strata on each side of the core of the arch are inclined in opposite directions away from the axis or crest; the core contains older rocks than does the perimeter of the structure.
  • A geologic formation that is water-bearing and which transmits water from one point to another.
  • Said of rock or sediment that contains, or is composed of, clay-sized particles or clay minerals.
  • A relatively clean quartz sandstone that is well sorted and contains less than 10% argillaceous material.
  • Formed or generated in place; specif. said of rock constituents and minerals that have not been transported or that crystallized locally at the spot where they are now found, and of minerals that came into existence at the same time as, or subsequently to, the formation of the rock of which they constitute a part. The term, as used, often refers to a mineral (such as quartz or feldspar) formed after deposition of the original sediment.
  • The Aux Vases Sandstone is named for the Aux Vases River in Ste. Genevieve County, Missouri, and the type section consists of outcrops in the Mississippi River bluffs at the mouth of the Aux Vases River. The Aux Vases consists of sandstone, siltstone, and minor amounts of shale and, locally, dolomite and limestone. It occurs in much of the area of the Chesterian Series. It crops out along the Mississippi River Valley in St. Clair, Monroe, and Randolph Counties, being particularly well exposed in the bluffs 2-3 miles southeast of Prairie du Rocher, Randolph County. In southern Illinois it crops out principally in Union, Johnson, and Hardin Counties.