Barns Batch Spinney is a 0.06-hectare

Hectare

The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...

 geological Site of Special Scientific Interest near the village of Dundry

Dundry

Dundry is a village and civil parish, situated on Dundry Hill in the northern part of the Mendip Hills, between Bristol and the Chew Valley Lake, in the English county of Somerset. The parish includes the hamlets of Maiden Head and East Dundry...

, North Somerset

North Somerset

North Somerset is a unitary authority in England. Its area covers part of the ceremonial county of Somerset but it is administered independently of the non-metropolitan county. Its administrative headquarters is in the town hall in Weston-super-Mare....

, notified in 1987.

The English Nature

English Nature

English Nature was the United Kingdom government agency that promoted the conservation of wildlife, geology and wild places throughout England between 1990 and 2006...

 citation says that Barns Batch Spinney is important because of the exposures which it provides of the lower part of the classic Inferior Oolite

Oolite

Oolite is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Hellenic word òoion for egg. Strictly, oolites consist of ooids of diameter 0.25–2 mm; rocks composed of ooids larger than 2 mm are called pisolites...

 limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 sequence of the Dundry area. It shows rocks lying stratigraphically below the Middle and Upper Inferior Oolite Limestones seen at Dundry Main Road South Quarry

Dundry Main Road South Quarry

Dundry Main Road South Quarry is a 0.7 hectare geological Site of Special Scientific Interest near the village of East Dundry, North Somerset, notified in 1974....

.

The geology at this site provides a section spanning the division of the Middle Jurassic

Middle Jurassic

The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....

 known as the Aalenian

Aalenian

The Aalenian is a subdivision of the Middle Jurassic epoch/series of the geologic timescale that extends from about 175.6 Ma to about 171.6 Ma . It was preceded by the Toarcian and succeeded by the Bajocian.-Stratigraphic definitions:...

 and Bajocian

Bajocian

In the geologic timescale, the Bajocian is an age or stage in the Middle Jurassic. It lasted from approximately 171.6 Ma to around 167.7 Ma . The Bajocian age succeeds the Aalenian age and precedes the Bathonian age....

 Stages and a sequence of rocks placed in the subdivision known as the discites zone, named after the characteristic fossil ammonite

Ammonite

Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...

 Hyperlioceras discites. This is one of the thickest sequences in Britain and may be used as the basis for defining these new subzones.

External links

• Barns Batch Spinney from GCR database