Bushwhacking to a Holey Boulder

Evelyn Greene stands before an Adirondack boulder that displays a

remarkable weathering pattern that has puzzled many geologists.

I'd follow Evelyn Greene anywhere. Sure, I've ended up with scratches and bug bites, muddy knees, soaking socks, and so forth almost every time I did, but wherever she takes me -- river islands, cedar swamps, quaking bogs, or almost impenetrable forests -- I always find something amazing in the end. Yesterday was no exception. Yesterday she took a group of us to see the holey boulder.

Twenty years ago, Evelyn's Garnet Lake neighbor, the environmentalist and author Bill McKibben, took her up to an Adirondack ridge to show her some fantastical rock formations: granitic gneiss pocked with very odd holes of different sizes, formations that even the state's chief geologist couldn't explain. More recently, Evelyn has been exploring some similar rock formations at the foot of Snowy Mountain near Indian Lake and, thanks to her diligent efforts to learn more about them, she has finally found a name to put to them: "tafoni" rock formations.

But just because she now knows what to call them, that doesn't mean that the cause of them is thoroughly understood. I looked up the definition of tafoni rock formations on Wikipedia, where I learned that the cause is not simply wind or water erosion but probably some kind of weathering process involving the mineral makeup of the rock. The exact cause remains mysterious. And what Evelyn finds really mysterious is how these formations occurred way up on an Adirondack mountainside, instead of the desert or seacoast where similar formations are usually found. She's asked a number of very smart geologists, and none of them knows the answer.

And here's another mystery: How did a solitary boulder containing tafoni weathering end up many miles away from Snowy Mountain in a woods near Thirteenth Lake? That's the one that Evelyn took us to yesterday. And it wasn't that easy to get to. No doubt it was the Ice Age glacier that carried this boulder from the mountaintop into the woods, but lacking a glacier and 10,000 years, we had to struggle through blow-down and muck and waist-high underbrush to reach the site.

We started out easily enough along a well-marked trail that led from a parking lot near Garnet Hill Lodge overlooking Thirteenth Lake.

Soon the trail started to climb as a pretty stream tumbled along beside us.

After about a mile we reached a pretty pond called William Blake Pond. Was this pond really named after the 18th-century English poet? Either yes or no, it called forth from me the urge to recite "Tiger! Tiger! Burning Bright." (Although to my chagrin I couldn't remember all the words.)

At William Blake Pond the easy trail led off in a direction we didn't want to take. Here's where the fun really started, as Evelyn led us through these thickets toward the site where the big boulder rested.

After a half an hour or so of bushwhacking, Evelyn spied our boulder silhouetted against the light at the top of a rise. But as this photo reveals, it would still take some time and effort to reach the site.

Huffing and puffing and wiping off sweat, we finally reached our goal, where Evelyn's grandson Calvin, light as a pixie, scrambled to the top.

Here's a close-up shot of the tafoni pattern, the holes surrounded by distinctive flanges.

With the sun now heading down behind the surrounding mountains, we couldn't linger too long to take in this mysterious phenomenon. No one wanted to bushwhack through all that blow-down in the dark! But we made it with light to spare or we'd possibly still be out there in the woods.

Driving home through the dark, I remembered more of the lines of Blake's "The Tyger," a poem that matched my mood of awe, and also relates to the mysterious forces that formed our amazing planet. So I repeat it here:

Tyger! Tyger! burning bright

In the forests of the night,

What immortal hand or eye

Could frame thy fearful symmetry?

In what distant deeps or skies

Burnt the fire of thine eyes?

On what wings dare he aspire?

What the hand dare seize the fire?

And what shoulder, and what art,

Could twist the sinews of thy heart?

And when thy heart began to beat,

What dread hand? and what dread feet?

What the hammer? what the chain?

In what furnace was thy brain?

What the anvil? what dread grasp

dare its deadly terrors clasp?

When the stars threw down their spears,

And water'd heaven with their tears,

Did he smile his work to see?

Did he who made the Lamb make thee?

Tyger! Tyger! burning bright

In the forests of the night,

What immortal hand or eye

Dare frame they fearful symmetry?