The link in post #1 is long dead. Here's the complete text, salvaged from the Wayback Machine ...
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HUMMM
Lee Stansfield
In June 2001 my ex-partner and I went for a walk around the headland on the spectacularly picturesque south western tip of the Lleyn Peninsula near Mynydd Mawr, North West Wales. It was a beautiful day with blazing sunshine, few people about, choughs circling the cliffs and playing amongst the remains of the buildings which once housed pilgrims on their way to and from Bardsey - Ynys Enlli - which was clearly visible across the water. The sea was not exactly wild, but choppy enough to splash the rocks with some force occasionally sending spray a metre or so into the air.
A short scramble down a creek and over some rocks to the sea brings you to St Mary's Well, a freshwater spring adjacent to the spot where the pilgrims boarded their boats to set off across Bardsey Sound. We had been here a couple of times before and the spot instils a sense of awe; with the waves crashing against the rocks you wonder how easy it was for the sick and the lame to get aboard the little boats which must have transported them over to the island on their journey of faith.
As we sat on the rocks next to the well watching the sea we suddenly became aware of a low humming noise. Dismissing it as a passing aircraft we at first ignored it but then as it seemed to become a constant throb we became curious. We climbed out of the creek where the spring was and scanned the skies for a plane or helicopter, but there was none to be seen. The higher we climbed, the less audible the sound became, until out of the creek and away from the rocks it disappeared altogether.
Deciding it was perhaps a boat near here we were sat we walked to the cliff top and searched for a craft below of any description which could have been generating such a noise from its engine. The only boat we could see was a small yacht to the east of Ynys Enlli in full sail. The distance and the type of boat this was, ruled that out as an option. Climbing back down the rocks to the well, we remarked once again how the sound increased. Indeed, one could even sense that it was eminating from the rock itself! The strange thing was, when I placed my ear against the rock the sound became neither louder nor quieter, just remained at a constant volume.
After about fifteen minutes of constant humming, the noise stopped, suddenly, leaving me and my partner to wonder what it was. Some kind of gentle seismic activity? Vibration caused by the sea against the rocks? Maybe it was a small boat that we hadn't seen. Or maybe it was the legendary "Hummadruzz"? Whatever it was kept both of us wondering for a long time afterwards...
Anybody else had a similar experience in this part of Wales?
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