The old woodsman isn't supposed to get lost. So why is he thrashing through the thick brush with a tearhole on his rugby shirt, sweat dripping from glazed eyes that dart angrily from one tree and one clearing to the next?

Because he's lost, and he's not supposed to be.

"That's a tricky trail," Freddie Jones had said as the woodsman left Jone's fishing hole at the edge of surging Difficult Run. "It's easy down here, but up there (pointing to hillsides of boulders) you can't always see your next mark. You have to hold still, do a little scouting before you move on.

"And it's rough. They named it right. You walk that trail and you'll sleep gooooood tonight."

They named it Billygoat Trail, and for all its buildup here its going to sound a little silly to confess it lies only five miles or so from the District line and runs along the banks of the Potomac.

One of the basic precepts of hiking is that you can't get lost if you follow a river. Especially if you have a map and have acquired over the years the simple understanding that the sun rises in the east and sets in the west.

The Billygoat Trail is a big circle route around Bear Island, a pile of jumbled boulders and dark, damp hollows that separates the C&O Canal from the Potomac River below Great Falls on the Maryland side.

The Canal towpath marks one edge, and that's easy. The other edge runs through the wilderness along the Potomac until it comes out high atop the Palisades overlooking the Mather Gorge.

It's a spectacular walk, which the National Park Service claims is only two miles long (not counting the Canal stretch).Because of all the ups and downs, it's a lot longer.

The problem is that it's so pretty the average hiker can't resist straying from the blue-blazed trail to unearth some racoon's lair, a beaver pond, a battered side trail down to an overlook, to watch carp rolling in a shallow cove.

When he gets through oohing and aahing, often he can't find his way back to the blue blazes.

So he crashes into the underbrush following his general north or south design, and before long finds himself in some dead end box canyon - either face to face with an endless poison ivy field: blocked by an unfordable creek or entering a wall of dark forests.

In short, the further one strays from the trail the harder it is to figure out where it ought to be.

No matter. There are a number of side trails thoughout the park and the next step is to pick up one of them. I tried that, thinking it the better half of scaling a cliff that lay ahead.

It was a delightful path, soft and easy walking through thin saplings and a clear route all the way. I wondered more when I came to a long-fallen tree across the path. The opening beneath was perhaps a foot high, but the path pushed on and under.

"Small people," I thought.

Another 200 or 300 yards and up popped the answer - a beaver pond, with a handsome dam and a home built of mud and sticks.

Already the sun was sinking over the Virginia shore. Could I ask for a room here?

The inn looked a little seedy, and the rooms were probably small, and the office wasn't open anyway. Back to the trail.

The plan had been to start at the southern end of Billygoat Trail and walk north to its exit below Great Falls, then stroll back to the car along the thoroughly unconfusing towpath.

I was better than halfway, but lost as a puppy on a roller coaster. Shadows lengthened and here it was July in Washington, and getting cool.

Time to save face and head back. So I crashed through the scrub brush and barked my knees on the boulders, following muddled common sense in a southern direction and listening for the roar of Difficult Run rapids. I knew the way from there.

I was still scratching my head and sweating, and I still hadn't found one blue blaze. Startlingly there came a rustling in the leaves ahead.

There were loud footsteps and labored breathing of something running. It was moving fast and coming straight for me.

"Done for," I thought, until from around the bend I spotted the sleek blue silk of its jogging shorts. It was a jogger, racing through the treacherous trails on his daily workout.

"Excuse me," I said sheepishly as he drew near, a man 15 years my senior and in the pink of health. "Where in the world are we?"

And he pointed with a finger to a spot on the tree I was leaning against. A blue spot. A blue blaze, in fact, the blaze said "Billygoat Trail."