Plas Cwmorthin

Plas Cwmorthin, the Rhosydd Quarry manager’s house, was built in 1860. It is not an unattractive building with a half-hipped roof and slate-hung end walls, sheltered, like many a manager’s house in the area, by a small plantation of trees.

At the end of the garden is a two-hole privy.

Inside it had four rooms on the ground floor (one a kitchen with a range) four large bedrooms and one small one, and a basement containing a large oven.

The interior walls were mostly thin partitions. The Plas was supplied with food by pony from Tanygrisiau with large stocks having to be laid in against the snowdrifts of winter.

From 1860 to 1932 the Plas was the residence of the Rhosydd Quarry agent.

The Williams family moved into one room from Rhosydd Terrace in the late 1930’s before moving out of the valley completely in 1948 – the last people to do so.

The photo shows the house in the 1870s with the Rhosydd manager’s family posing at the front.

Although this dwelling has deteriorated over time it is by far the strongest built in the valley and well sheltered by trees. Little capping will be required but some trimming of tree branches that threaten the walls will be needed. The photo below shows the recent state of the building


The photo at the top of the page shows the Plas in its heyday with some of the Thomas Jones family in the garden.  According to Cecil Jones of Porthmadog the lady on the left is Thomas Jones’ daughter Elizabeth. The maid is holding Cecil Jones’ grandmother Elizabeth whilst Mr Jones’ great-grandmother – Thomas Jones’ wife Elizabeth – is by the front door.

Lewis & Denton sumarise the three quarry agents who lived here 

The agent was the most important man in the quarry, being responsible for day-to -day running and indeed often shaping long-term policies by his advice to the board. In most quarries except the largest, the agent was a man of the people who had risen to the top by his own merits, and however English the company he was almost inevitably Welsh, since almost all his workmen were too. In all its life, from 1853 to 1948, Rhosydd had only three agents.


Thomas Jones, the first, was born at Llandwrog in 1815 and gained his practical experience at Cwmmachno Quarry. He served at Rhosydd from 1853 to 1878, when he retired to Portmadoc.

He died in 1885.

He was clearly a knowledgeable and effective manager, a disciplinarian but on excellent terms with his men. In his time, a Rhosydd workman who left would often return before long, sadder but wiser, saying that there was no other quarry like it.

Thomas Jones, a Methodist deacon, had a sharp manner ­and a stick he made himself felt with - but a great sense of humour. He had no truck with "Mr" or "Thomas": he had to be called Tomos Jones and nothing else; but behind his back his nickname was Hen Ewyrth,-  Old Uncle.

William Morris, born at Tanygrisiau old farmhouse, became clerk at Rhosydd in 1862, then the Rhosydd shipper at Portmadoc, and finally agent in 1875. He retired in 1906 to Penmorfa where he died about ten years later. He too was a Methodist deacon.

We know little of him, except that he must have been competent since in his time Rhosydd reached its peak and saw many mechanical advances. But it seems that at least towards the end of his term he tended to be cautious and conservative, and thereby perhaps unfitted to meet the crisis of the Great Fall.

His successor was a most colourful character, a loud, swearing, friendly no-­nonsense man with the facility of getting on with people, who is still remembered with affection.

Evan Jones was an entirely self-made man. Born in 1867, he began his career as a slatemaker at Maenofferen, then became a rockman and moved to Groesyddwyafon Quarry to the east of Ffestiniog; becoming agent at Groes for a few years before moving to Rhosydd.

As agent he was enterprising and energetic, and was defeated not by any shortcomings of Rhosydd or of himself, but by economic facts.      

After Rhosydd closed he returned to Groes.    But he had other interests too.

During the First War, with the rank of captain, he commanded a Welsh Miners Tunnelling Company in France and was twice mentioned in dispatches.

He vacated the Plas due to the poor health of his daughter Ellen Anne.

He was active in local politics: at various times chairman of the Ffestiniog UDC and of the County Council, Sheriff of the county, Deputy Lieutenant, JP; and in 1935 he was knighted for his political work.

He died in 1949.