Birdshill Quarry

Overview

Birdshill Quarry is a very small disused limestone quarry west of Llandeilo, notified as a Site of Special Scientific Interest in 1984 and covering just four tenths of a hectare. What the quarrying exposed is a richly fossiliferous section of the lower Ashgill Birdshill Limestone — the type locality for several species of trilobite, brachiopod and bivalve, and unique as a conodont-bearing horizon in the Welsh lower Ashgill.

History

The industrial history of this quarry is not recorded in anything read for this record: no owner, no dates, no output, no workforce. What is recorded is that geologists have recognised the quarry exposures at Birdshill to be of great importance for nearly 150 years — which, from a citation prepared in the 1980s, puts scientific attention on the site back to the earlier nineteenth century and implies the quarry was open by then. Llandybie and the country around Llandeilo carried both mining and quarrying from the 1840s to the 1950s, served by a local mineral railway that took coal and limestone to markets across south and west Wales; this quarry belongs to that landscape, though nothing read here ties it to that railway or to any particular concern. The site was notified as a Site of Special Scientific Interest in 1984. It covers 0.4 hectares at national grid reference SN 601321.

Geology

The quarry exposes a richly fossiliferous section of the lower Ashgill Birdshill Limestone — Ordovician rock, not the Carboniferous limestone quarried more widely in this part of Wales, and a distinction worth holding on to. It is the type locality for several species of trilobites, brachiopods and bivalves, and is unique as a conodont-bearing horizon in the Welsh lower Ashgill, rocks of that age being poorly represented. It is described as a site with a key biostratigraphic fauna. The fossils record life some 425 million years ago, when much of this area lay under a shallow sea inhabited by trilobites — a group of primitive arthropods, now extinct — together with brachiopods and bivalves. More recent work has found conodonts, microfossils which have let geologists date the strata accurately and compare the Birdshill section with rocks of similar age in America and Sweden.

Geological setting: Sedimentary Beds and Seams (surviving physical example)

Workings

A very small surface quarry — the notified area is 0.4 hectares, about an acre. Nothing read for this record describes its faces, depth, plant or method of working; what is documented is the section it left behind.

Closure

No closure date has been established. The quarry was disused by the time of its notification in 1984 and had been of interest to geologists for close to a century and a half by then. Nothing consulted here narrows it further.

What remains

A designated Site of Special Scientific Interest of 0.4 hectares, valued for the section and the fauna it exposes rather than for anything remaining of the quarrying.

The quarry faces themselves, which are the reason for the designation. Nothing read for this record describes a surviving quarry structure.

Related mines

• Talar Wen Quarry — Two very small disused Carmarthenshire roadside quarries a few miles apart, both notified as Sites of Special Scientific Interest for the Ordovician limestone sections they expose and the trilobite and brachiopod faunas in them — Talar Wen in the Llandeilo Series, Birdshill in the later Ashgill.

Nearby mines

• Dolaucothi Gold Mines — 10.3 km NE
• Talar Wen Quarry — 11.4 km SE

Straight-line distance, within 15 km. Show on the map.

Recorded claims

Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.

• Birdshill Quarry was notified as a Site of Special Scientific Interest in 1984, covers 0.4 ha, and lies at national grid reference SN 601321. ¹
• The site is a richly fossiliferous section of the lower Ashgill Birdshill Limestone, the type locality for several species of trilobites, brachiopods and bivalves, unique as a conodont-bearing horizon in the Welsh lower Ashgill, and a site with a key biostratigraphic fauna. ¹
• Geologists have recognised the quarry exposures at Birdshill to be of great importance for nearly 150 years, and the fossils record life some 425 million years ago when the area was covered by a shallow sea. ¹
• More recent investigations have revealed the presence of conodonts, microfossils which have helped geologists determine the age of the strata accurately and allow the Birdshill section to be compared with rocks of similar age in America and Sweden. ¹
• Birdshill Quarry is a Site of Special Scientific Interest in Carmarthenshire, Wales. ²

Photographs & further reading

Sources

1. (primary) Birdshill Quarry SSSI citation — Countryside Council for Wales / Natural Resources Wales
2. (secondary) Birdshill Quarry — Wikipedia

Record created: 4 September 2026 · Last researched: 5 September 2026