Month: March 2017

One piece to the poop bag puzzle

I think I found a missing piece to the puzzle of dog poop bags.

All us who know the C&O Canal towpath know about dog poop bags. Leash in one hand, bag in the other, at the strategic moment he or she swoops down to capture their prize and tie a good secure knot. What happens next is the puzzle.

I’d like to think that most dog owners do what’s responsible and the little bags end up in the household trash. But evidence to the contrary lays alongside the towpath path like little blue, yellow, and black sentries.

A dog poop bag patiently awaits
its owners.

It’s not just that I don’t like dog poop bags. It’s that there’s something going on here that transcends the subject of an unsightly and particularly disgusting kind of trash. I’ve noticed that the bags are not randomly tossed aside, like beer cans or plastic water bottles. Instead, most are carefully placed at the base of a tree trunk or post, by a rock, even in the end of a hollow tree. Why do people do this? I have some ideas, which I will write about later. But for the moment, I just want to pass along this one incident, since it’s breaking news. It also happens to be good news.

The bag I found today was leaning against a tree on the side of a little path that connects the canal towpath to the parking lot at Carderock. It was white and a little bigger and floppier than most.

I knelt down to take a picture of it. (Yes, I really do take photos of dog poop bags, and I’m not the only one. There’s at least one other, naturally a Brit. ). Just then I noticed a threesome approaching me on the towpath—a man, woman, and a dog. Happy for the chance to give my shot a little context I waited for them to get closer so I could make it a foursome.

They must have seen me. What were they thinking? I knew what I was thinking—that I must have looked pretty foolish.

I headed to my car, and just before I got in I glanced back and saw something I had never witnessed before: The man picked up the bag and took it with him. Their car happened to have been parked right next to mine. I could see that they were a nice couple, with happy smiles and scruffy clothes. Their dog looked friendly.

Of course I’ll never know if my obvious interest in their dog poop bag had anything to do with their asserting ownership of it. I don’t think it did.

Riverbed on a hilltop

It looks like the Potomac river bed,
but minus the shells and fish.

I went poking around a rocky riverbed today that ran along the crest of a hill. It looked just like the bottom of the Potomac River, though without the fish and the shells. It also looked a little like a NASA photo of ancient riverbeds on Mars.

In all three cases, the giveaway was that the rocks are rounded. Some were as small as jelly beans, others as big as melons. I picked up a baseball-sized rock, and it felt good in my hand. Most were shades of cream, grey, or reddish brown. Some were startlingly white. They lay scattered about on the dark forest floor, like super-sized fairy dust.

They told a story about a restless river, a Potomac that shifted one way and then another, cutting down into the landscape and leaving evidence of its meanderings on what would become the hillsides we know today.

The rocks were mostly quartzite, a tough, hard material forged by heat and enormous pressure from sandstone lying deep under the earth’s surface millions of years ago. But there are no quartzite deposits here in the Piedmont province of the Potomac valley. The nearest is over 30 miles away in the Blue Ridge mountains, near Harper’s Ferry, West Virginia. According to geologists, chunks of the rock broke off from the mountains long ago and tumbled into the river. The river transported them downstream, bumping and scraping against themselves and the river bottom, like semiprecious stones in a rock tumbler.

Created by heat and pressure,
shaped by a raging river.

The river as sculptor. How long did did it take the river turn these jagged, angular pieces of rock into the rounded objects lying around me? Did it carry them downstream inch by inch, mile by mile, over hundreds or even thousands of years? Or did it whoosh them down in one or several full swoops?

Until recently, most geologists would have backed the slow-going scenario. According to the longstanding geological theory called uniformitarianism, geological events unfold in measured, incremental changes. But in recent decades, geologists have been taking a  livelier view of how geology works. The new theory, called catastrophism, recognizes the important role that sudden, violent events have played in shaping our world.

The catastrophist view is the apparent winner, according to the authors of a paper that describes the origin of similar deposits on the Virginia side of Great Falls a few miles away. They postulate that the rocks were transported and shaped by “one or a few” massive floods that were double the magnitude of the 1936 flood, which is the biggest on record.

The authors of the paper couldn’t pinpoint when these events took, though it could have been as recently as 70,000 years ago. Or it could have been much longer go. The rocks on the hillside have told part of their story, and we’ll just have to wait for the rest.

Herons and hawks

I went running on the towpath at Carderock today, and the first thing I saw were patches of spring beauties poking up through the fallen oak leaves. Years ago I dug up some of the plant’s tiny tubers to verify their edibility. It was a culinary experiment that won’t be repeated.

Efficient predator with a taste for
whatever it can swallow.

Further along I saw five Great Blue Herons stalking fish in a part of the canal where it widens. Four of the leggy birds were facing each other, cocking their heads to track the movements of the little sunfish that were emerging from their winter lethargy. Every couple of minutes one of the herons would unleash its rapier bill and come up with a wriggling fish in a garnish of detritus. If this were a National Geographic nature video I would expect to learn that the birds were acting cooperatively by bunching the fish together to make them easier to catch, the way a pack of wolves herds elk. Actually, I think the four of them were just there because the fish were there.

Watching all of this was a hawk in a tall tree overhead. My glasses were back in the car, but I could still make out a band across the bird’s light colored breast that marked it as a Red-tail Hawk.

I continued my run. As usual my pace was so slow that I might just as well be out looking for someone to strike up a conversation.

“Did you see the hawk?” the man asked. He gave me a friendly smile under the brim of cap with the name of a US military ship.

“Yes, I think it was a red-tail,” I replied.

“No,” he corrected me. “the tail was too short to be a red-tail. It was a red-shouldered.”

He had also seen the herons, and informed me of their scientific name. “Ardea herodias,” he said. “‘Ardea’ is heron in Latin,” and ‘herodias’ is “heron” in Greek. So ‘heron heron.'” Still smarting from getting called out on my hawk identification skills, I made a note to shun people who flaunt their knowledge of scientific names.

On the way back I saw that the hawk was gone. But nearby I heard the unmistakable “cree, cree, cree” call Red-shouldered Hawks make in staking out their territories. But I still think the one in the tree was a red-tail.