Earthwatcher's photos with the keyword: sill

The little inlet of Pwlldawnau and the headland Penbwchdy, viewed from adjacent to the Pembrokeshire Coastal Path at National grid ref. SM 8808 3692 (a nice place for a sandwich). The prominent pale rock horizon consists of sandstone and conglomerate at the base of the Ordovician age Ogof Hen Formation. This rests unconformably on the underlying shales of the Cambrian age Lingula Flags. The far headland of Penbwchdy is comprised of a microtonalite sill, an igneous intrusion. If you zoom in on the photo you can see near-vertical columnar cooling joints in the sill.

Traeth Llyfn is an attractive west-facing sandy beach on the north Pembrokeshire coast, viewed here looking south-east from the north headland in the late afternoon sun when just about everyone else had gone in for tea. The cliffs are mostly in the dark grey Aber Mawr Shale Formation (Ordovician), steeply dipping to vertically bedded, with a few thin tuff bands (volcanic ash bands). There are igneous intrusions at the north end of Traeth Llyfn including a dolerite/gabbro sill which forms the un-named north headland to the bay (here). Access to Traeth Llyfn is by boat or by a bracing walk along the cliff top path from Abereiddi Bay 3/4 of a mile away. There are no facilities here and no vehicular access. A lovely place...

Traeth Llyfn is an attractive west-facing sandy beach on the north Pembrokeshire coast, viewed here looking north from the coastal path. The cliffs are mostly in the dark grey Aber Mawr Shale Formation (Ordovician), steeply dipping to vertically bedded, with a few thin tuff bands (volcanic ash bands). There are igneous intrusions at the north end of Traeth Llyfn: (a) a dolerite/gabbro sill which forms the un-named northern headland to the bay and (b) a thin dolerite sill just a bit to the south which is visible in the photo forming the white-weathering rib just left of centre. Access to Traeth Llyfn is by boat or by a bracing walk along the cliff top path from Abereiddi Bay 3/4 of a mile away. There are no facilities here and no vehicular access. So it is very unspoiled.

Traeth Llyfn is an attractive west-facing sandy beach on the north Pembrokeshire coast. The cliffs are mostly in the dark grey Aber Mawr Shale Formation (Ordovician), steeply dipping to vertically bedded, with a few thin tuff bands (volcanic ash bands). There are igneous intrusions at the north end of Traeth Llyfn: (a) a dolerite/gabbro sill which forms the un-named northern headland to the bay and (b) a thin dolerite sill just a bit to the south which is visible in the photo forming the greeny-buff rib and some of the rounded boulders in the immediate foreground. Access to Traeth Llyfn is by boat or by a bracing walk along the cliff top path from Abereiddi Bay 3/4 of a mile away. There are no facilities here and no vehicular access. So it is very unspoiled.