- Usage in publication:
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- Speeds limestone member
- Modifications:
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- Named
- Dominant lithology:
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- Limestone
- AAPG geologic province:
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- Cincinnati arch
Summary:
Name Speeds limestone member introduced in this report for shaly limestone about 18 in. thick underlying Silver Creek member of Sellersburg at Speeds quarry.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Speeds formation
- Modifications:
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- Revised
- AAPG geologic province:
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- Cincinnati arch
Summary:
Rank raised to formation. In region of fullest development, unit is a hard blue crystalline limestone, which weathers to irregular thin layers and spalls. Thickness 1 to 3 ft at Sellersburg, 13 ft at Lexington, and 1 to 3 ft in Jennings Co. In some areas, lies between Jeffersonville formation below and Silver Creek formation above; in other areas, underlies Deputy formation (new).
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Speed lithofacies, member
- Modifications:
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- Revised
- AAPG geologic province:
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- Cincinnati arch
Summary:
Names Speed and Silver Creek are applied to lithofacies of Hamilton rocks. These lithofacies may be used as members in southern part of outcrop belt.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Speed Member
- Modifications:
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- Overview
- AAPG geologic province:
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- Cincinnati arch
Summary:
The Speed Member of the North Vernon Limestone of the Muscatatuck Group consists of gray, granular, poorly sorted shaly thin-bedded, fossiliferous limestone. The thin-bedded, platy appearance on exposure is partly due to many brachiopod shells. The Speed is interbedded with gray dense and argillaceous to sublithographic limestone of its overlying intimate facies, the Silver Creek Member. Unconformably overlies the Jeffersonville Limestone. Unit is recognized both along the Devonian outcrop area in southern IN and in the subsurface. It is completely eroded eastward but reaches a thickness of 9 ft along Big Camp Creek, east of Deputy in Jefferson Co. May be either early Givetian or Eifelian is age.
Source: GNU records (USGS DDS-6; Reston GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).