Return of the sponges

It was a bad afternoon for a river expedition. A light rain had started to fall, pushed by a gusty breeze. But this was about sponges, and it couldn’t wait. By tomorrow morning, the remnants of Hurricane Ida would sweep into Potomac country. Heavy rains would flood the river, producing swift currents that would scour away anything not firmly anchored to the bottom.This would be my last chance this year—perhaps forever—to see my delicate and enigmatic creatures.

The thrill of discovery. I call them “my sponges” because I had found them in 2011, the first sighting of sponges in the main stem of the upper Potomac River. I also call them “creatures,” because a lot of people don’t realize that they are animals, not plants, and are moreover the first animal to emerge on earth, possibly an astonishing 890 million years ago.

The most lively thing about D. radiospiculata are its jumping jack-like spicules. Otherwise it just sits there like a head of cauliflower.

I was thrilled by that discovery 10 years ago, and even more so when the sponge expert at the Smithsonian Institution identified the sponge as a species rarely found along the eastern seaboard. Its scientific name was Dosilia radiospiculata for the delicate radial structure of its skeletal parts. I proudly signed a release to donate my specimen to the Smithsonian collection.

I felt a kinship with the legendary naturalist explorers of former times, whose exploits I so admired. Now I had exploits of my own. But I quickly I learned that not all scientific discoveries are equal. A person can live their entire life without thinking even once about a freshwater sponge. When I told one person about my sponges, her response was, “Let’s go see what’s on the buffet table.”

Then the sponges disappeared, also after a flood, like the one that was threatening to hit now. In the following years I searched for them, all up and down the river, but found no trace.

But even though my discovery was perhaps not very interesting, it was significant. Look at Darwin and his earthworms! As it turned out, my discovery and the events that followed would transcend the subject of sponges, and help me to better understand the world and our place in it.

Here my guide would be Potowmack the Trickster, the spirit of the river, who excelled in exposing our foibles and puncturing our pride, particularly as regards our place in the natural world.

A nice afternoon for my son and his family of mucking around in the river turned into another chapter in the sponge saga.

Sponges redux. And now, after 10 years of absence, the sponges reappeared. I had taken my son Matt and his young family out for a Potomac afternoon of getting wet and muddy. As we were preparing to leave, Matt casually remarked, “Hey Dad, isn’t that one of those sponges you told me about”? I was astounded.

We were in a little cove, its water murky from the silt we kicked up boarding the canoe. But we could still make out the bottom and its tufts of algae, dead leaves, and smoothed river stones. And the sponges, a whole colony of them.

By now everyone was settled in the canoe and clearly anxious to be on their way. I snapped off a couple of more photos, and off we went. I would return as soon as I could to spend some quality time with these long lost creatures.

One last encounter. Now here I was by myself, paddling hard through the rain and the weeds and around the rock ledges. I heard some distant rumbling to the west, imagining that Hurricane Ida was already arriving. It turned out to be aircraft making their approach to Dulles Airport, some of them probably carrying Afgan refugees. Most of the world was focused on the Afgan evacuations, or the hurricane, or covid-19. My mind was on sponges.

I angled across the river heading for a gravel bar, a spot where you can still find remnants of the canal that George Washington built to skirt the rapids. I wondered if Washington also saw the sponges. Would he have cared?

The gravel bar was already occupied by an increasingly agitated flock of Canada geese. They bobbed their heads and honked and cackled and pooped and then took to the air, flying low over the water, still honking and pooping.

I pulled my kayak up on the shore, picking my way around the piles of goose droppings. The water was a little discolored, but clear enough to see.

Crushed and confused, I search the little cove for any sign of sponges.

The trickster returns. But there was nothing to see. The sponges had vanished, once again gone without a trace.

I was disappointed, but at the same time intrigued. No doubt about it. Here was Patowmack the Trickster at work once more.

What happened? I had read somewhere that ducks will eat sponges. I’d guess that geese eat a lot of the same things as ducks. I imagined a flock of geese coming upon a colony of sponges, and in no time devouring them all—but with an exception. For along with the sponges the geese also pick up the sponges’ gemmules, those tiny spherical reproductive bodies. The geese fly off and land somewhere else, always honking and pooping, and depositing the gemmules. If the current is swift, the gemmules just become part of the organic soup that washes downstream to who knows where. But if the geese land in some protected cove or back water, the gemmules could produce a new colony of sponges come next season.

I later asked my son Matt what he thought of my scenario. After all, he was the one who found the sponges. He also has a doctorate in ecology, so he should know about such things.

Matt listened politely to me, and then came up with a more prosaic explanation. The sponges looked pretty shopworn, he remembered, and they smelled bad. Later he had to wash his hands over and over to get out the stink. Probably the sponges were just dying, he said. Their season had come to an end, like the leaves starting to fall from the trees or mushrooms turning black and slimy. The bits and pieces of their bodies—including the gemmules—those tiny time capsules—probably lay  among the algae and dead leaves in that same little cove. With any luck, the gemmules could produce another colony when the conditions are right. I later learned that scientists describe this stage in the sponge’s life cycle as “gemmulation and degeneration.”

River keeps its secret. I like both explanations. I like mine because it illustrates the lengths the human imagination will go in finding a cause for anything and everything, even in the absence of any real evidence. The more complex the cause, even if it enters the realm of the conspiratorial, the greater its allure. Taken to the extreme, a search for causes could inspire elaborate myths and liturgies and the creation of priestly hierarchies. (If it seems like I’m straying a little far from a pooping goose, blame Potowmack the Trickster.)

In contrast, Matt’s explanation looked at the disappearance of the sponge from the standpoint of the sponge. The life cycles of natural creatures operate independently of our assumptions and expectations. It’s the creatures that are calling the shots, whether we like it or not.

Whatever actually happened in that little cove is the river’s secret, at least for now. I don’t have the persistence to figure it out, and Matt is mainly focused on getting tenure.

Let’s just call it a thought experiment. We can name it Schrödinger’s Sponges. It’s as if the sponges were locked away in a box, just like the famous physicist’s imaginary cat. Is the cat dead or alive? Unless we open the box to see, it occupies both states at the same time. The same goes for the fate of the sponges. Until we have data based on observation, all explanations are valid.

I think this would be good problem to leave to some graduate student with a lot of time for research and little interest in public recognition. 

Peaceful and easily overlooked, a little cove branching off from the river probably holds the answer to the mystery of the sponges.

A compass and the distant crack of a rifle

It was early summer when I returned to the Potomac River bluff where I had found the rock with the carved cross. I removed the piece of rotting tree limb I had placed over it on my last visit and brushed away the fallen leaves. As the image came to view I thought how it always looked smaller and more crude than I had remembered, but just as enigmatic, with its main shaft topped by a diamond-shaped head and a line like a carpenter’s angle draped over one of the crosses’ arms.

Shaped like a sharks tooth, this
flake of quartzite could be
an Indian scraping tool.

I still had no idea what the image signified, or anything else about it, even after many visits. I’ve found plenty of fascinating clues, but none of the bits of glass, pottery, stone, and some oddball things as well, added up to anything. Each was a little story completely in and of itself. It was like astronomy before Newton.

This time, though, I was a little more optimistic. For I had come armed with an idea and some new information.

North to where? First, my idea. I took out my cell phone, flicked on the compass app, oriented the arrow north, and laid it alongside the cross. Just what I suspected: The digital age and the age of stone crosses lay in almost perfect alignment.

It was a “eureka!” moment. But while Archimedes’s flash of insight led to many scientific and technological discoveries, mine went nowhere.

What did it mean that the rock image pointed north? Why would a north-pointing rock be of any use to anyone? It’s not like people might forget which way is north, and needed a reminder. Was it a navigational aide for Santa Claus?

So as far as I could determine, my clue didn’t point to anything—except north.

Cleanly cut piece of post looks like concrete,
but it’s not.

Crinoid connection? Next, my new information. On my previous visit I had found what looked like a four-sided concrete post. Only the surface didn’t feel like concrete. It was smoother and more cushy. I had slipped a little piece in my pocket to check it out at home.

When I later looked at my sample under a lens, I saw that the ‘”concrete” was actually a mass graveyard of fossil marine fragments, a lot of them the familiar mini-donut segments of crinoid stems. It was limestone, probably formed sometime in the Ordovician period, around 450 million years ago. The closest limestone deposits occur about 30 miles away in the Hagerstown Valley.

A lens reveals that the post is made
from a mash-up of marine fossils.

Why would anyone go to the trouble of bringing carefully squared limestone posts to this place? Are they markers? Are they related somehow to the north-pointing “compass” rock?

I had already searched the web for old property markers. None looked anything like my stone. I did another thorough survey of site, hoping to find more limestone posts whose position would relate to each other in some way. I did find a couple more, but their placement appeared to be random.

Northward bound. Kneeling by the rock, I stared again at the cross, waiting for it to send me some signal. Maybe it was telling me to go north to find the answer. (Or maybe I had read too many Dan Brown thrillers.) At any rate, I set off, pushing through bushes and scrambling over rocks and logs. But aside from some broken bottles and rusty beer cans, I didn’t find anything, at least nothing that I could decipher.

See sidebar: Clues that go nowhere and beyond

This was getting frustrating. Could the rock be signaling some astronomical message? A lot of famous stone relics were created to mark astronomical events. Could my stone be a kind of mini-Stonehenge? I looked up to the heavens, but everything seemed in order—no eclipses, solstices, or meteor showers, just a Red-bellied Woodpecker hammering away at a dead snag at the top of an oak tree.

Shot from a tiny rifle casing echos
across the years.

Distant rifle shot. I resumed my search along the bluff that overlooked the river. I found more glass shards and a few intact bottles, some old, some recent. Also rusted fragments of a car and a little rifle shell casing.

I carefully brushed away the dirt on the base of the casing and just barely made out “WRACO 25-20,” aka Winchester .25-20. You don’t see many of these any more. The cartridge was first introduced in1893 for the famed Winchester 1894 lever action rifle of Buffalo Bill and John Wayne fame. It hung around for years as a favorite of farmers, trappers, and pot hunters, since it’s relatively quiet and does minimal damage to meat and hides.

Farmer John was no match for
the crafty fox.

I  imagined what might have happened here many years ago. “John, John!” cried the farm wife. “The grey goose is gone, and the fox is on the town!”  Out ran John, just in time to see the fox—and the flapping goose—disappear over the hillside. John took a shot just to please his wife, and the crack of the rifle came back as an empty echo. The ejected casing landed where I found it.

Clues but no conclusion. Then there was the matter of that shallow pit near my stone. I slid down into the bed of leaves and broken branches, and started to feel around with my hands, hoping that copperheads by now had found cooler and moister refuges down by the river. I felt something metallic, which I pulled. It was a rusty metal strap, anchored below ground. To what? Without a shovel, I had no way of knowing.

When I later viewed the pit from a different angle I noticed what seemed to be a ring of rocks around its perimeter. Maybe it meant nothing—what else do you do with stones you find when you did a hole? Or maybe it told a story.

Before leaving I took a final look at the rock inscription before covering it over with leaves and the chunk of rotted tree limb. Clues were piling up, but so far they added up to absolutely nothing. Maybe things would start to come together on my next visit.

Or maybe I’ll never solve the mystery of the “compass rock.”

At the same time, my many hours on this bluff have taught me a great deal, things maybe even more important than the meaning of that particular rock or any of the other shreds of evidence I have found. What I have learned is this:

Here was a patch of forest overlooking the Potomac, lovely in its own right, but otherwise seemingly unremarkable. Yet, as I discovered through the bits of glass and flakes of stone, the circles of rocks and odd bits and pieces of human detritus, that spot has a conscious dimension that stretches back—who knows?—decades, centuries, maybe much longer. Even on a silent winter’s day, when nothing moves except the river, there are voices here.

Clues that go nowhere and beyond

A good friend of mine prepared for a visit to his doctor by compiling a thorough documentation of his medical history.  His doctor took one look at the spread sheets and the columns of numbers, and said something to the effect of, “I’m not interested in data.”

My friend—a doctor himself— was shocked. For him, as a member of a scientific and medical tradition stretching back to the ancient Hellenic philosophers, empirical evidence is the basis for knowledge. But my friend’s doctor probably already knew what specific data he would need to make a diagnosis and design a treatment. He wasn’t interested in seeking knowledge, but in solving a problem.

Unlike my friend’s doctor, I have no plan or methodology for finding the clues I need to pierce the enigma of the cross carved in stone I found on the bluff overlooking the Potomac River. For the most part, I just stumble around in the forest, happily finding clues, many of them intriguing, but none that have actually brought me closer to understanding anything significant about that odd carving. This is hardly surprising, because it would take the training and the skills of an archeologist to know what to look for and how to make sense out it, and I’m not an archeologist.

But through it all, I have found something important that goes beyond the enigmatic rock. As I write in my main article:

Here was a patch of forest overlooking the Potomac, lovely in its own right, but otherwise seemingly unremarkable. Yet, as I discovered through the bits of glass and flakes of stone, the circles of rocks and odd bits and pieces of human detritus, that spot has a conscious dimension that stretches back—who knows?—decades, centuries, maybe much longer. Even on a silent winter’s day, when nothing moves except the river, there are voices here.

Here’s a visual summary of what I’ve found.