Cader Idris – 5 Cannon Holes
Penrhyngwyn slate quarry lies above Ty Nant, on the north side of Cader Idris. A free Snowdonia National Park car park (with toilets) at Ty Nant provides the best starting point for an ascent of the mountain via either the Fox’s or Pony Paths. An excellent day out on the hill can be had by going up the Fox’s path, across the peaks of Pen y Gader and Cyfrwy and descending the Pony Path, collecting this and possibly 8 other caches on the way. For climbers, this cache is on the way to the classic mountaineering route, Cyfrwy Arête (500ft Diff.). The cache site is above the ffridd wall, on CROW access land but please don’t climb over dry stone walls to get there. The best access is up either of the public rights of way and then to follow the ffridd wall along. I discovered the site of the rock cannon whilst out teaching micro-navigation on a Mountain Leader Training course in October 2007. Unusually, these rock cannon aren’t included in Griff R. Jones’ book. I think that they have been drilled into a roche moutonee (see GC12RVR for more geomorphological details).
Rock cannon can be found all over north-west Wales, especially near mines and quarries. The cannon were created for firing on celebrations & holidays and were used from the end of the 1700’s until black powder stopped being used in the slate industry. The introduction of sticks of gelignite led to a different style of cannon being devised that didn’t need any holes in the rock.
Making a rock cannon was hard work. All of the holes and grooves for fuses had to be cut with hand tools (please remember this if what you find doesn’t look that impressive!). The cannon were cut into the tops of cliffs, slabs of rock or large boulders, the biggest having nearly 200 holes and the smallest having just 2. Each hole was about 5” deep and 1” in diameter. The later cannon had grooves connecting the holes which were filled with black powder to make the fuse. The channels had to make a long enough fuse for each separate bang to be heard and each flash to be seen.
Penrhyngwyn was a small slate quarry and mine, in very poor quality rock. The spoil tips can be seen from the road, as can the rusty staining from large amount of iron in the slate. The quarry probably mainly produced slabs of slate, with what roof tiles that were made being for local use. Products were taken away on horse carts and the peak of production & employment at the quarry was 250 tons by 40 men in 1883. Penrhyngwyn quarry closed in 1901. Apart from the spoil tips, there is now little to see on the site as most of the buildings have collapsed or been demolished by the landowner. The only entrance to the underground workings is now gated & locked.
Other Rock Cannon Caches
Garreg yr Ogof – Rock Cannon 1 (GCY6FC), Bluemaris – Rock Cannon 2 (GC102HQ), Garn – Rock Cannon 3 (GCYFCX)
More Information
&“The Rock Cannon of Gwynedd” by Griff R. Jones ISBN 0-9533692-1-8
8Wikipedia – Rock Cannon
&“A Gazeteer of the Welsh Slate Industry” by Alun John Richards ISBN 0-86381-196-5
8www.penmorfa.com
&“Meirionnydd” Climbers’ Club Guides ISBN 0-901601-63-2