GeoMon Home - Porth Amlwch
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This Earthcache is part of a series found in the Geopark of
Anglesey (Geomôn). This internationally recognised Geopark, the
first island ever to receive Geopark status, covers some 720 square
kilometres and has 201 kilometres of coastline. With rocks spanning
4 Eras and 12 Geological periods, 1,800 million years of history
has fashioned more than 100 rock types.
Geological sites (Geosites) have been selected for scientific
quality, rarity, aesthetic appeal and educational value. The
Geopark Earthcaches series is based around these Geosites. Their
interest may also be archaeological, ecological, historical, or
This is a harbour area. Please keep control of children and dogs as there are steep sides and cliffs.
The Watch House - GeoMon Visitors Centre
Vast seams of copper ore were discovered at Mynydd Parys in 1768, and the next half-century saw intensive mining here, resulting in one of the most extraordinary industrial landscapes in Europe.
In their heyday the Parys mines were among the wonders of the world; visited by men like Michael Faraday and James Watt, the best scientists and engineers of the day.
The output from the mines dominated the international copper market and nearby Amlwch grew from a small cove between two steep rocks into the worlds major exporter of copper.
The port became so busy and important that an Act of Parliament had to be passed in 1793, enlarging and regulating it.
Under the inspired management of Anglesey-born lawyer Thomas Williams, novel uses were found for the copper, such as sheathing for the hulls of wooden warships. Nelson's flagship HMS Victory was able to gain speed and manoeuverability, crucial to the success at Trafalgar.
At this time, Amlwch even minted its own copper coins!
After the mines became exhausted, Amlwch port developed its own thriving ship-building industry, launching vessels famous for their speed and beautiful lines.
Porth Amlwch retains many original buildings the Copper Bins, the Watch House, the sail loft and the Workshop Chimneys.
The Sail Loft, belonging to William Thomas's shipyard, is most unusual in that it has a sloping floor and window lintels made from ship's timbers in which the "trunnel" holes can still be seen. The Amlwch Industrial Heritage Trust's exhibition can be found here now. In 2001 Amlwch Industrial Heritage Trust opened a heritage trail around the features in Porth Amlwch. A leaflet explaining the historical features of the trail around the mountain can be obtained from The Sail Loft Heritage Centre in Porth Amlwch.
The Watch House with its small lighthouse was built around 1819 and extended in 1835. The building, used mainly by hobblers who were responsible for amongst other things moving vessels in and out of the port, was also a meeting place where captains met socially in the evenings to yarn. This is soon to open as The GeoMon Visitors Centre, displaying facts and guides about the Geology of Anglesey.
In order to complete this cache, e-mail the answers to the following (NOTE: Please DO NOT respond to the questions in your logs.):
a) Paynter's water driven saw mill was powered by water from where?
b) Locate the Anglesey Rock Clock. On The RHS wall there is an information board. What do the letters mNH stand for and what colour is the area depicted on the map?
c) Take a photo of yourself and/OR your GPS at N53.24.904 W004.20.015 with The Watch House in the background.
Further information on the geology of Anglesey can be found on the fantastic Geomôn website:
Information on the Amlwch Industrial Heritage Trail can be found on their website:
Information was sourced from literature by Dr Margaret Wood and Dr John Conway of GeoMôn Anglesey Geopark and Amlwch Industrial Heritage Trust
(No hints available.)