MineArchiveSmarts Quarry
| Location | East-north-east of Mynydd-y-Garreg, Carmarthenshire — 51.7525, -4.2839 (approximate) |
|---|---|
| Commodity | Sandstone |
| Type | Quarry |
| Worked | No reliable opening date has yet been located.–Disused by 1987, when the site was notified |
| Maximum depth | No reliable working-depth figure has yet been located. |
Overview
A small quarry east of Mynydd-y-Garreg, notified as a Site of Special Scientific Interest in 1987 and covering 2.6 hectares. Its face cuts Namurian quartzite, and on one bedding surface it preserves abundant star-shaped feeding traces made by burrowing bivalves — apparently unique in the Basal Grits of South Wales, and enough to show that these sands were laid down in an estuary rather than on an open shore.
History
Nothing read for this record establishes when the quarry was opened, by whom, or what the stone was used for; a hard quartzite in this district would most likely have gone for building or road material. It was disused by the time the site was notified as a Site of Special Scientific Interest in 1987. The site sits half a mile east-north-east of Mynydd-y-Garreg, above the Gwendraeth valley — limestone-quarrying country, where the Carboniferous Limestone was worked at scale for the steelworks and for burning to lime. This quarry cut the younger sandstones above it instead, and what it left behind turned out to matter for a reason no quarryman would have had any use for.
Geology
The quarry presents a section in Namurian quartzite — part of the Basal Grits at the foot of the Millstone Grit sequence, laid down as the Carboniferous seas gave way to the deltas that would become the coalfield. Its importance is a single bedding surface, covered with abundant stellate feeding traces produced by bivalves: star-shaped patterns radiating from a central burrow, made by an animal reaching out in every direction from one position to feed. Those traces appear to be unique in the Basal Grits of the Namurian in South Wales, and they are evidence rather than curiosity. Comparison with modern examples of the same behaviour indicates the environment the sand was deposited in — an estuarine setting rather than a simple shoreline — which makes the quarry, in the citation's words, an important site for environmental studies in the Namurian.
Geological setting: Sedimentary Beds and Seams (surviving physical example)
Workings
A quarry of 2.6 hectares. Nothing read for this record describes the face, the depth or any plant, and the designation is for the section it exposes rather than for anything the quarrying left.
Closure
No closure date has been established. The quarry was disused when the site was notified in 1987 and nothing consulted here narrows it further.
What remains
A designated Site of Special Scientific Interest of 2.6 hectares, valued for the Namurian section and the trace fossils on its bedding surface.
The quarry face, and in particular the bedding surface carrying the feeding traces, which is the reason for the designation.
Related mines
- Crûg Farm Quarry — Two Carmarthenshire quarries protected for what their faces expose rather than for anything they produced, and for opposite kinds of evidence: Crûg Farm for the body fossils in its Ordovician limestone, Smarts for the traces an animal left behind in Namurian sand.
Nearby mines
- Cynheidre Colliery — 6.9 km E
- Gwendraeth Colliery — 8.4 km E
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.
- Smarts Quarry was notified as a Site of Special Scientific Interest in 1987, at national grid reference SN 424084, covering 2.6 ha. 1
- Smarts Quarry presents a section in Namurian quartzite and is principally of importance for abundant, bivalve-produced stellate feeding traces on a bedding surface, which appear to be unique in the Basal Grits of the Namurian in South Wales. 1
- By comparison with modern examples the traces indicate an estuarine rather than a simple shoreline origin for these sediments, making the quarry an important site for environmental studies in the Namurian. 1
- The SSSI lies approximately 0.5 miles east-north-east of Mynydd-y-Garreg in Carmarthenshire. 2
Photographs & further reading
The official notification, one paragraph long, which explains why a disused quarry face is protected: a bedding surface of bivalve feeding traces that appear nowhere else in the Namurian Basal Grits of South Wales, and which show these sands were laid down in an estuary.
View sourceSources
- (primary) Smarts Quarry SSSI citation, Carmarthenshire — Countryside Council for Wales / Natural Resources Wales
- (secondary) Smarts Quarry — Wikipedia
Record created: 4 September 2026 · Last researched: 6 September 2026