Another face carved on an ancient standing stone in the UK may have been discovered.

Last month, BBC News Online reported the claims of one archaeologist who said there is a carving of a face on one of the major stones at Stonehenge.

Now, a second archaeologist believes he has seen another face, this time on the side of one of the Callanish stones in the Western Isles of Scotland.

The face is looking to the left

To many, the Callanish circles and stone avenues are even more impressive than Stonehenge. They are set against the backdrop of magnificent mountains and the sea on the Isle of Lewis.

Visitors say the stones have a presence that surpasses Stonehenge on the cultivated Salisbury plain.

Ancient stones enthusiast Martin McCarthy is a self-proclaimed sceptic when it comes to the suggestion that heads and faces have been carved into Neolithic standing stones, but he did get a surprise when studying some photographs he had taken at the Callanish complex a few years ago.

The lines mark out the features Martin McCarthy sees

"One stone had a pattern on it that could have been a head, so I poked around through my other pictures and found a reasonably clear picture of the stone in question," he told BBC News Online.

"It has a very clear - to my eyes, anyway - left-facing head with nicely proportioned eye, nose, cheek, lips and chin."

Trick or treat?

Is it really another face or is it the eye playing tricks?

Humans are programmed to see patterns, especially faces, in natural objects. As babies, we learn this skill when we try to focus on our mother's face.

As others look and make up their own minds, Martin McCarthy remains a sceptic. "Whilst I do believe that this is probably just a random alignment of naturally-weathered shapes, I'd be delighted to be proven wrong.

"But to my eyes it is a more convincing head than the face that was recently reported on one of the megaliths at Stonehenge. "

Missed markings

In October, Dr Terrence Meaden started a major debate about the nature of Stonehenge and the origin of the face that, if real, has gone unnoticed for perhaps 4,000 years.

Other archaeologists are in the process of studying it. Many are remarking that, face or not, it is amazing that nobody has pointed out the markings before.