Moel yr Ogof
mountain (655m) in Gwynedd
Moel yr Ogof is a summit in Snowdonia, Wales. It is a subsidiary summit of Moel Hebog and a sister peak to the lower Moel Lefn.
There is an asbestos trial mine located on the summit. A small seam of white asbestos was discovered however insufficient amounts to commercially mine.
Geology
The summit of Moel yr Ogof is composed of a brecciated rhyolite, diagnostic of gravitational collapse in a rhyolite dome.
Surrounding the crown of the mount is a geological unit consisting of alternating bands, of varying thickness, of pillow basalts and a green/grey sandstone that is of mafic origin, potentially derived from the pillow basalt itself.
The pillow basalt is relatively well preserved in places, where devitrification rims clearly outline the individual pillows. It is composed of dark green/black, very fine crystalline, basaltic rock, which has weathered to a dark red/brown colouration due to the presence of iron minerals.
The sandstone member of the unit is a pale green/grey, fine to medium grained, well sorted sandstone. It shows good cross-bedding and rare ripple structures indicating a tidal depositional environment.
This brief starts where responsible research should: with the source description of “Moel yr Ogof” as mountain (655m) in Gwynedd. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the places & architecture register because the source frames it as mountain (655m) in Gwynedd. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Maps, plans, fabric surveys and administrative records can establish how the site’s name, extent and function changed over time. The source revision retrieved here is dated May 23, 2026. The linked authority identifier is Q6890142. Authority coordinates are 53.009, -4.153. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank.
A single description cannot reconcile every naming convention, rebuilding phase or administrative transfer associated with a place. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
- Jurisdictional context
- Routes into maps and plans
Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “Moel yr Ogof”, its source revision and the description used here.
- Expand the search: follow Moel yr Ogof primary sources, Moel yr Ogof archive and Moel research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Moel yr Ogof”?
- What physical evidence or contemporary plan supports the description?
- Which authority defined the place, boundary or structure at the relevant date?
Search terms from this dossier
This entry incorporates text from “Moel yr Ogof” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.