Trilobite-bearing limestone, exotic sills, dykes and fossilised trees.

Anglesey's rocks provide a detailed record of the events leading to the formation of southern Britain. Formed between 650 & 300 Ma, they include high grade gneisses, a granite pluton, metasediments, sandstones, mudstones and the famous Anglesey Blueschists. There are also Paleogene dykes, abundant glacial features, a number of NE–SW faults and large sandstones blocks possibly marking the location of an ancient subduction zone.

This excursion has been cancelled because of the coronavirus outbreak. We hope to reschedule it for 2021.

This excursion has been cancelled because of the coronavirus outbreak. We hope to reschedule it for 2021.

1800 Ma gneiss, Precambrian metasediments and fossil stromatolites, the famous Port Askaig Tillite (possible "Snowball Earth"?), low grade metamorphic Dalradian rocks retaining original sedimentary structures, reactivated and reversed extensional faults, substantial mineralisation, 60 Ma igneous intrusions (opening of the Atlantic Ocean) and a large selection of Quaternary Ice Age features.

A journey through the magma chamber of an early Palaeogene volcano, with visits to significant localities of igneous, sedimentary and metamorphic rocks

Outcrops of the Blackhall Limestone and disused quarries and, if time permits, a visit to the lime kilns on the foreshore.

Terrestrial fossils from Romer's Gap and a rich fauna of marine fossils.

Lower Carboniferous sedimentary rocks, Upper Carboniferous sills and late glacial and postglacial deposits

A classic east-west cross-section through folded Dalradian metasediments, part of the Appin Syncline