The Aymestry Limestone is a fossiliferous limestone of Gorstian age (

Upper Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...

) deposited in a warm shallow sea near the eastern margin of the

Iapetus Ocean The Iapetus Ocean (; ) was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale (between 600 and 400 million years ago). The Iapetus Ocean was situated in the southern hemisphere, between the paleoco ...

. It occurs in England in the Ludlow Group, between the

Upper Upper may refer to: * Shoe upper or ''vamp'', the part of a shoe on the top of the foot * Stimulant, drugs which induce temporary improvements in either mental or physical function or both * ''Upper'', the original film title for the 2013 found fo ...

and Lower Ludlow Shales. It derives its name from

Aymestrey Aymestrey ( ) is a village and civil parish in north-western Herefordshire, England. The population of this civil parish, including the hamlet of Yatton, at the 2011 Census was 351. Location It is located on the A4110 road, about 7 miles no ...

(sic), Herefordshire, where it may be seen on both sides of the River Lugg. It is well developed in the neighbourhood of Ludlow (it is sometimes called the Ludlow limestone) and occupies a similar position in the Ludlow shales at Woolhope, the Abberley Hills, May Hill and the Malvern Hills.

Description

In lithological character, this limestone varies greatly; in one place it is a dark grey, somewhat crystalline limestone, elsewhere it passes into a flaggy, earthy or shaly condition, or even into a mere layer of nodules. When well developed it may reach 50 ft. in thickness in beds of from 1 to 5 ft.; in this condition it naturally forms a conspicuous feature in the landscape because it stands out by its superior hardness from the soft

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

s above and below. The most common fossil is '' Pentamerus knightii'', which is extremely abundant in places. Other brachiopods, corals and trilobites are present, and are similar to those found in the Wenlock limestone.

References

External links

* * Geologic formations of England Silurian England Silurian southern paleotemperate deposits Limestone formations Mudstone formations Sandstone formations Fossiliferous stratigraphic units of Europe Paleontology in the United Kingdom {{UK-geologic-formation-stub

Description

See also

References

Further reading

External links