These cookies are absolutely essential for our website to function properly.
We use Google Analytics to measure how you use the website so we can improve it based on user needs.
These cookies may be set by third party websites and do things like measure how you view YouTube videos.
Amgueddfa Cymru – Museum Wales
'Talcen Mawr', Penrhyn Quarry, Bethesda (pre 1895). ‘Talcen Mawr’ was a large volcanic intrusion which was blasted away on the 27th April 1895.
