Things of stone and wood?

The latest mystery to bewilder us on our Great Wall journey – apart from old standbys like “Can anything else happen to delay us?” “When are we getting there?” and “Whose idea was this in the first place?” – comes from the field of natural history.

The question came up as we were walking in a valley near the village of Shentangyu. The day before we’d been forced off the wall by a cliff we couldn’t get around, and were taking a farmers’ trail through some orchards on what we hoped would be (and mercifully, unusually was) a short detour back to our planned route.

As we were walking, we started to notice that whenever our walking sticks hit the “rocks” below, they made a soft thud rather than the usual annoying clacking sound.

“Does this feel like stone to you?” Brendan asked as he tapped the ground with my walking pole.

I did the same. The ground looked like stone but actually felt soft. When we tapped on it with our sticks, it crumbled easily, like a wet log.

We walked up a bit further, tapping at the ground.

“I don’t think this is stone,” Brendan said. “It’s soft all the way up here (tap tap), and here (tap), and here (tap).”

We began to think that what we were standing on was not rock, or not entirely rock, but what seemed to be the remains of an enormous – and I mean enormous – tree. And not just one, but all over this orchard we noticed these “trees.”

Conducting an examination

You can get a sense of the scale by comparing the log to the full-sized tree in the background

There was no sign of branches or roots on the trees, but then they were clearly very, very old and the smaller limbs had probably just rotted away. In other respects they looked just like fallen, hollowed out logs. They were rounded, had probably been four or five metres in diametre when whole, and were long and straight. The logs had a clearly distinguishable grain, and in most places their texture was soft and crumbly, like rotting wood.

This log was quite soft

The fluting and rounded edges of this piece reminded me of old redwood logs in Northern California

But as we looked further, we saw that in other places the logs were more like stones, hard and resistant to crumbling. With the assistance of our trusty Unsolved Mysteries magnifying glass, we could see that at least parts of our logs had mineralised, i.e. they were most definitely rocks.

This piece has broken apart in a very rockish way

The white portion is definitely mineral

As we found more and more of these odd rockish logs and treeish stones, we came to the conclusion that what we were looking at were neither rotting logs nor petrified trees, but an ancient forest that was actually in the process of petrifying.

Here the wood grain is distinct, but you can also see what look like flecks of rock

This piece defies categorisation, by us at least

Unfortunately, neither of us has any geological, botanical or paleontological training, and we both have a penchant for making things up, or at least coming up with glamourous theories for our little humdrum discoveries. So we don’t really know if we found a petrifying forest, or just have overactive imaginations. We did a little internet research, and though we did find that there are several geological parks in the area featuring petrified wood, we weren’t able to find anything that would let us know what we’d seen.

If you have any geological expertise, or know someone who does, have a look at these photos or put us in touch with your rockhound friends. If we can’t find someone who can tell us whether we were looking at wood or stone, or both, whether we’ve found an ancient petrifying forest will have to remain another Unsolved Mystery of the Great Wall.

We’d like to thank everyone who has helped us with the other mysteries we’ve published, and particularly those who left enjoyable and insightful comments on our post on The Valley of a Hundred Fengsui. Simon, it was great to hear a perspective from someone with a military background, and your suggestions strike us as quite likely – we’ve read of wall in the eastern brick portion being designed to create interlocking fields of fire, so that would seem logical in the west as well; and yes , the valley is an important thruway to Datong. Jim, to hear from you is a welcome blast from the past for me (Brendan), and thanks for an interesting parallel from North America. Marg, welcome aboard, and we have read that particular numbers of signals sent from individual towers could indicate approaching troop strength, so it seems quite possible that signals from multiple towers could perform a similar function.

Looks like we’ll have to get those fridge magnets made up!

We can count about 40 beacon towers in this photo alone

When we first laid eyes on (and christened) the Valley of a Hundred Fengsui, we didn’t have any trouble identifying the structures we saw. There was no need to speculate about a prehistoric race of supermen or alien invaders. No, we knew that we had stumbled upon a valley that was unusually rich in fengsui, or as we generally call them on the blog, beacon towers.

Emma filming the Valley

If you’ve seen The Lord of the Rings: Return of the King and remember the scene where Pippin sets a large tower alight, sending a message calling for help across an entire mountain range, you know how the system of fengsui worked. All along the wall, from Jiayuguan to Shanhaiguan, beacon towers were built so that a fire signal (feng) or smoke signal (sui) sent from one would be visible from the next in line, making it possible to transmit military information back and forth rapidly across the entire border region. According to one military manual from the Tang Dynasty (618-907 AD), when the system worked according to plan a message could travel 1000 kilometres in a day and a night.

So what’s the big mystery? Well, we might know what fengsui are, but we don’t know why there are so many – more than anywhere else we’ve been – in this broad, open valley northeast of the city of Datong in Shanxi province.

Normally beacon towers are most common where the terrain is rough and lines of sight are interrupted; in these areas, you might see a beacon tower on just about every peak or prominence. But for some reason, in the Valley of a Hundred Fengsui, where you could easily see a signal sent from five kilometres away, the Chinese decided to build more than 100 beacon towers over a distance of less than 20 kilometres. Between some of the towers in the valley, there would be no point in sending a smoke signal – in the time it would take to light a fire you could just stroll over to the next tower for a chat.

Sunset falls on the Valley of a Hundred Fengsui

If you can tell us why the wall-builders constructed more than 100 nine-metre high signaling towers in a valley as flat as a pancake (and be verifiably correct), you could be the proud owner of the world’s only Walking the Wall fridge magnet. If none of you can, then the raison d’etre of the beacon towers in this remote, windswept valley in Shanxi province will have to remain another Unsolved Mystery of the Great Wall.

The subject of this episode

In which our two wandering detectives discover in the remote canyons of China’s Helan Shan mountain range a most peculiar set of small earthen formations – perfectly formed, uniformly distributed and dusted with a topping of white powder.

Was this an unfortunate outbreak of acne on the face of the Earth? The secret target range of a squadron of scatological birds? A display case of frosted mud pies created by an alien race of Nigella Lawsons?

We settled on the last option as our leading hypothesis. Emma ran her finger through the frosting of a pie and sampled it.

“I think we can rule out icing sugar,” she said.

I knew a Christmas pudding was too good to be true

Thus thwarted, we turned to more prosaic possibilities. The mud pies were always located in dry desert washes, at the mouths of canyons some distance from the nearest town. It appeared they were put there deliberately and carefully, most likely by humans, at some cost in time and money. And it was obvious they would wash away with the first decent rainstorm.

The mud pies in an especially large wash

The best we could come up with is that the pies might serve as a method of measuring the flow of these desert washes after significant storms. The local terrain clearly shows that some very large flash floods come out of the mountains during the summer “rainy” season. There’s probably no way of getting out to the area by car when the canyons are flooding, and all of the water would sink through the gravel before reaching any practical observation point. However, after the event it would be possible to drive out, see which pies washed away and which didn’t, and thereby derive an estimate of the volume of the flood.

We couldn’t think of any rational purpose the white powder might serve.

If you have a better solution, remember, there’s a Walking the Wall fridge magnet waiting for you if you submit a verifiably correct answer. Until someone does, the mud pies will have to remain an Unsolved Mystery of the Great Wall.

The only man-made construction visible from space!
Contains the bodies of one million men!
Has enough material to wrap around the Earth 15 times!

Sorry folks. This post is not about perpetuating the extraordinary, fantastical myths that have shaped and distorted contemporary images of the Great Wall of China.

No. This is the first in a regular series of posts dedicated to unanswered questions surrounding the Great Wall. The deep questions that Brendan and I ask each other almost every day. Questions like “What in tarnation is that?”

Having no experts in Chinese military history or archaeology close at hand to answer our questions, we thought we’d turn to that renowned source of collective wisdom and bulldust – you, the netizens of the blogosphere. When we have a question for you, please feel free to write in with your guesses, educated or otherwise (keep it clean!). If you have actual expertise or know someone who does, better yet.

Verifiably correct answers win a Walking the Wall fridge magnet!! (See applicable conditions below.*)

The subject of this episode

So, here goes. Unsolved Mysteries of the Great Wall Part One has now begun. See that ball above? What is it?

Whatever it is, it’s damn heavy

Brendan and I walked past this hefty monument a few days ago. It was lying in a ditch opposite the wall, surrounded by leaves. I made to roll it over with my foot but couldn’t even get the thing to budge an inch. So Brendan, probably against medical advice, bent down to pick it up. What won’t he do for a photo?

Rock solid and weighing in at approximately 35-40 kilograms (or a lot heavier than our packs at least, which are about 20), the ball is grey in colour and has a protective outer coating.

A close-up showing the protective outer coating, which has been damaged

Jumping to the most obvious of conclusions, lying as it was next to the wall, we thought it looked awfully like a cannonball, yet from which decade or century we have no idea. Maybe we’ll find out, maybe we won’t. But unless you act, this will remain an Unsolved Mystery of the Great Wall.

*****

*Prizes awarded upon our return to Australia, provided we can find someone to make fridge magnets cheaply.