In a bid to lure even more tourists to these celebrated stretches of sand, the Shoalhaven City Council, whose patch covers much of this area, has developed the 100 Beach Challenge, an online geo-locative game which challenges sun-worshippers to visit as many of these beaches as possible.

Never one to forgo an opportunity to explore more of our region's great outdoors, last week your akubra-clad columnist enthusiastically embraced the contest which requires participants to log in to a geographical point on each beach as proof of their visit.

However, I was forced to do a double-take after noticing 'Singing Stones Beach' listed on the challenge's map just north of Pretty Beach in the Murramarang National Park. 

While regular readers may recall this column's delight several years ago in uncovering the singing rocks of Kiandra, an outcrop of boulders in the Snowy Mountains which if tapped with a stone produce a melodic resonance, I'd never heard of a singing beach. 

I don't think I'm alone in my ignorance, for there is absolutely no mention of such a place on our country's official website of beaches (www.beachsafe.org.au), nor in Geoscience Australia's Gazetteer of Australia Place Names (www.ga.gov.au/placename). In fact, after an internet search revealed only handful of obscure references implying the existence of such a beach, I began to wonder if it was merely a marketing ploy by organisers of the 100 Beach Challenge to entice more curious contestants.

One way or other, I had to find out. So earlier this week after tossing my towel, togs and audio recorder (to hopefully document the phenomenon) into the Yowie mobile, I headed down the Clyde.

It's mid-week and the yowie mobile is the only car in the gravel carpark at the end of Pretty Beach Road. I intended to ask the ranger at the beach's National Parks office about the authenticity (and origins) of the singing stones, but it's deserted too, so armed only with my recorder, camera and map I traipse down the grassy knoll and onto Pretty Beach.

This 350 metre-long strip of sand, popular with campers on the weekends, is definitely living up to its name today — the swell is gentle (not sure what that means for the pitch of the singing stones) and the only tracks on the creamy sand are those of endangered Pied oystercatchers.

Thankfully it's near low tide too which makes navigating around the southern rock platform of the beach much easier than if picking gaps between waves to dash to the next boulder.

About 50 metres offshore are a pod of about 10 bottlenose dolphins frolicking in the turquoise-coloured water. Their animated trills are an attempt to willingly lead me to the stinging stones, either that or mocking laughter prompted by observing yet another landlubber searching in vain for them.

Further south and just past the imaginatively named O'Hara Island #1, a pair of fishermen, each lugging a full bucket of catch, walk off the rock platform and towards me. 

"Are the stones singing today?" I ask earnestly.

Their response is unexpected. Possibly thinking I'm some misguided Mick Jagger fan, they leer incredulously at my cumbersome 1970s style audio recorder, shake their heads, and keep walking.

Oh well, according to my crumpled copy of the challenge map, my destination should only be a few hundred metres away, so I press on. 

Minutes later, I finally reach Singing Stones Beach. Shaped like a wine glass and surrounded by a naturally-occurring amphitheatre of rock, it's a charming cove. However, there's one critical feature missing — stones. There are only a handful of golf ball sized pebbles scattered on the sand and any ostensible 'singing' they make as they roll up and down the beach with the incoming tide is inaudible.

A beach of stones just can't vanish into thin air, can it?

Trying to think of a logical explanation, I speculate that perhaps a storm has washed them away, or possibly buried them under tonnes of sand. 

Hoping for the latter, I start digging and with the gusto of the notorious gopher from the 1980 comedy, Caddyshack, I feverishly excavate a large area of holes at close intervals. 

With almost half the beach pock-marked and starting to resemble a moonscape, I finally hit jackpot — at almost 1 metre deep my fingernails scrape along a bed of stones. 

Although content that they haven't completed vanished, buried so far under the sand, it's obvious that these stones won't be singing today. So listening back to my newly recorded sound track featuring huffing and puffing from digging interspersed with prolonged sighs of disappointment, I trudge back to the carpark.

With the closed sign still swinging in the breeze at the campground office, I stop at the first sign of life, the nearby Kioloa Beach Store. Behind the counter making milkshakes is long-time local Jenny Bellett who is genuinely surprised when I ask her about the stones. 

"We've never had a tourist ask about them," she explains, adding "it's actually a closely guarded secret by some locals".

She's even more shocked when I reveal that their singing has been silenced by several tonnes of sand.

"They were in full voice last time I was there", she asserts, adding "they make a spectacular rumble as the waves wash them in and out of the cove."

According to Bellett, the stones have been enthralling locals for well over a century. "As a child we lived next door to a lady in her 90s and she told stories how she'd often go down and listen to the lovely singing," she says.

Up the road at the Bawley Point Newsagency it's a similar story. Newsagent Larissa Behns is stunned to hear of the buried stones. "It must have just happened, as only last week I gave someone directions to them," she says, adding, "and they never returned to say the stones weren't there!"

A browse around the shopping centre reveals that the fabled stones don't feature on any postcard, nor even as a passing snippet in any local history books on display. In fact, there doesn't appear to be one single skerrick of written information in town.

In fact, I begin to wonder if their untimely disappearance is part of an elaborate conspiracy by a group of shovel-wielding locals who got wind of my intention to highlight their stones in this very column. That said, it would have taken some hernia-popping grunt to move that much sand.

A later chat with local ranger Roger Dunn sets the record straight.

"Occasionally, due to sea conditions they get covered in sand," adding "come back in a few weeks and they'll probably be singing again."

I might just do that. Only next time I'll be sure to hike in from Pebbly Beach, for if the stones vanish again, at least I'll be able to tick a few more beaches off my list. 

Singing Stones Beach: Located in Murramarang National Park, on the Pebbly Beach – Pretty Beach walking track. Easiest access is from the carpark at the end of Pretty Beach Road. Allow for a 20-minute walk each way. Pretty Beach is about 2.5 hour's drive from Canberra via Batemans Bay.

Where do the pebbles come from? Their origins are remarkable. According to Phil Smart, retired south coast geologist, "two hard fine-grained siliceous Palaeozoic rocks – Rhyolite and Chert, account for almost all of the rounded pebbles at Singing Stones Beach." Smart further explains, "about 280 million years ago these rocks were transported from an ancient inland mountain range by ice in glaciers and then on icebergs, falling as 'drop stones' on the continental shelf of Gondwana when the icebergs melted," adding, "in geologically recent time, they have been plucked from their host Permian sedimentary rock strata in sea cliffs and rock platforms and deposited by big waves on the beach".

Why do they sing? "As the waves wash over the beach the water tumbles the stones into each other at speed making the singing sound," explains Smart, who believes the reason these rocks sing, and many on other beaches don't "is because these rocks are crystalline, are very fine grained and are composed of very hard minerals".

More: www.100beachchallenge.com