On an unseasonably warm midwinter day, Stephanie LaRose Lewison arrived at Fall Kill Creek in Poughkeepsie, N.Y., with hip waders, a ladder and white ski poles. After descending the ladder into the creek’s swift current, she balanced herself on the poles and began bricking.

“It’s a defining characteristic of myself,” said the 31-year-old geologist, of her passion for collecting the ubiquitous fired-clay blocks almost universally regarded as heavy, dirty and generally worthless. To date, she has amassed more than 400 bricks—not far from the proverbial ton—in her Poughkeepsie basement.

She keeps them neatly displayed on shelves just above her glass-bottle collection, a decision that led one fellow brick aficionado to label her an “optimist.”

Like other collectors, she looks for bricks stamped with words, pictures, symbols or numbers set in a rectangular recess called a frog. Unmarked bricks, called “vanillas,” are usually ignored.

Ms. Lewison is member No. 1,518 of the International Brick Collectors Association. The organization, which frowns on buying or selling, won’t assign bricks a monetary value. It insists that one brick is worth another in trade only.

“When you place a value on something, you attract people who want to make a profit,” said the association’s librarian, Jim Graves. If bricks were worth money, he added, “it would encourage people to go out and liberate them.”

Mr. Graves, 73, has between 3,000 and 4,000 bricks in his yard in Wichita, Kan.

“I don’t mind being called crazy,” he said.

Instead of searching eBay, IBCA members travel to thrice-yearly swaps where collectors trade from truck beds and spread out bricks to give away. A bell rings and attendees race around, filling their arms.

“It’s amazing what people are willing to share,” said Ms. Lewison, who said she once scored a rare New York Central Railroad example. Between swaps she mails bricks to collecting colleagues in flat-rate boxes.

In the early 1900s, the Hudson Valley led the world in brick production. New York City building codes mandated fireproof materials, and vast deposits of clay lay within a short boat ride of the growing metropolis. But regulations changed, the Depression hit, and construction firms turned to concrete and steel. Of the 100-plus brick manufacturers that operated along the river in 1910, none remain today.

Now collectors scavenge river banks, former brickyards, constructions sites and landfills for the industry’s remains.

Much of that history is preserved in the 3,000-strong New Netherland/New York Brick Archive at Fordham University, maintained by Allan S. Gilbert. The anthropology professor uses chemical analysis to compare bricks from dig sites with ones in the archive.

Calling the humble brick a crucial artifact in the history of urbanism, Mr. Gilbert said he is “awed” by its significance.

The gurus of Hudson River brick collecting are Andy van der Poel, 50, and Fred Rieck, 74. They met recently to “talk brick” in Mr. Van der Poel’s garage in Kingston, N.Y., where the high-school physics teacher keeps his finely curated collection on floor-to-ceiling pine shelves. His passion is such, he said, that if he isn’t careful, “I’d have no family and a whole lot of bricks.”

The amateur scholarship of these two brick buffs has exceeded the published literature on bricks. Now they are correcting the texts and advising other collectors on forums like brickcollecting.com.

“Some of the stuff I’m looking for is rare—it is 100 years old, but it wasn’t a fine art. It was crude and industrial,” said Mr. Rieck, a retired electronics equipment inspector for New York’s Office of General Services, who has at least 1,000. “Who gave a hoot about bricks?”

The two friends pore over old maps, obituaries and industrial records to find out what company made what brands, where the brickyard was and who owned it. They have solved the mysteries of Shamrock, Dwyer, Roberts and about 400 others. A few brands, such as *DK* and VF, still elude them.

Mr. Van der Poel’s favorite brick is unmarked, except for the tiny footprint of a child who stepped on the clay before it was fired.

“When Fred and I have done lectures, I bring this along,” he said. “You’re only going to find that when you’re out there doing some digging.”

On one brick hunt, they did find a corpse.

“It didn’t look gory,” said Mr. Rieck. “A cowboy boot with a pant leg coming out of it. A skull like it was just planted in the sand.” They took their bricks home, then called the sheriff. It turned out to be someone who had been reported missing months before from a nearby beach.

Mr. Van der Poel said he once knew a collector who tried to pry a desirable brick out of a stranger’s front steps. “I’m not going to take a brick out of somebody’s house,” Mr. Van der Poel said. He and Mr. Rieck do have their strategies, but the duo are careful to ask permission, when there is someone around to ask.

The best time for bricking comes after the snow melts because ice shifting along the Hudson’s shoreline can uncover fresh examples. Another choice time, said Mr. Rieck, is right after a fire.

When people inevitably ask what they are doing, casing a freshly burned building or mucking about on the river, Mr. Van der Poel hands them a business card reading “Hudson River Brick Collector.”

“It legitimizes us,” he said.

ERIK MICHELSON BARELY glanced at the gorgeous views from Breakneck Ridge, views many New Yorkers give up a precious Saturday to see. As he scrambled past hikers on a recent spring afternoon, he had eyes only for the trail and the feet that may or may not stay on it.

Mr. Mickelson designs trails full-time for the New York-New Jersey Trail Conference, which maintains more than 2,000 miles of free trails in the region. His job: to get inside hikers’ minds and anticipate their movements.

“They vote with their feet,” said Mr. Mickelson.

An hour and a half north of Manhattan, Breakneck Ridge is one of North America’s most popular day hikes, in part because the Metro-North Railroad stops right at the trailhead just north of Cold Spring, N.Y. All a visitor has to do is follow the small squares of color, called blazes, into the woods.

At least that is the idea.

“I never thought of trail design as something somebody does,” said Chris Bertinato, 33 years old, an engineer at the Lamont-Doherty Earth Observatory in Palisades, N.Y., who spent a recent Saturday volunteering for the nonprofit Trail Conference. “It’s almost like you take it for granted.”

“Laying a trail out is part art, part psychology, part science,” explained Mr. Mickelson, 44. Wearing insect-repelling pants and a backpack sprouting a drinking-water hose, he spends nine-hour days hauling his tall, angular frame through brambles and brush, scouting trails that independent-minded hikers will adhere to.

Problem is, if a path doesn’t take day trippers to an overlook or waterfall they want to see, they will create their own “social trail,” increasing the human impact on the land. To thwart this, Mr. Mickelson tries to anticipate renegade footfalls.

“You’ll lay it out, you think you’ve done it well, and then they make a shortcut and you’re like, ‘Damn, why didn’t I see that?’ ” he said.

Social trails occur, for example, when a hiker sees the next leg of a switchback below, then cuts down the hill to shorten the distance. On a busy trail like Breakneck, people will also walk around one another, widening the path. To discourage these two-lane tendencies, Mr. Mickelson will cleverly guide a route through steep rocky terrain, along cliffs or between boulders.

Peter Jensen, president of the Professional Trail Builders Association, said sustainable trails are more enjoyable because they go unnoticed. A muddy or rutted one forces walkers to focus on their feet instead of what they came to see.

“A well-built trail,” said Mr. Jensen, “really blends into the background.”

Every year Mr. Jensen’s 90-member organization adds eight or 10 new trail-building companies. “Right now trails are hot,” he said.

Growing up in Virginia Beach, Va., Mr. Mickelson cared most about surfing. But when the waves were flat, he hiked in the woods behind his house.

After receiving a degree in plant science from the University of Arizona, he spent 10 years in the golf industry. He tried teaching for a while, he said, but decided he needed to be outside.

“As a surfer I prefer a trail that kind of surfs the mountain,” he said. “It unfolds in front of you, it flows.”

Mr. Mickelson’s trails follow the rolling contours of a slope with a gentle sense of momentum. But to keep what he calls “that East Coast flavor,” he includes occasional steep “punchy” rock sections.

One of Mr. Mickelson’s worst enemies is water. He thinks about it constantly, looking for its source, predicting its movements and determining how a path can be laid out or adjusted to minimize erosion.

A poorly planned trail becomes a stream bed during heavy rain, carving the hillside as it descends. Hikers contribute, too. Last year Breakneck Ridge saw more than 100,000 hikers, 1,426 in a single day. Each foot takes a little of the mountain with it.

How people descend from the ridge is one of Mr. Mickelson’s current concerns. One descent is overused and eroded, and the other has hikers walking back through a dark, shoulderless highway tunnel.

He proposed a new descent that would shorten the current three-hour loop. State biologists denied the plan, saying it took people too close to protected habitats, like rattlesnake dens.

Mr. Mickelson can see their point. “I feel bad sometimes about putting a trail where there wasn’t one,” he said. “There are times when I kill some insect, or we overturn a rock and there’s a snake or a lizard that gets injured,” he said. “I am vegan, so that does make it harder for me.”

Daniel Yu, 40, a technology consultant from Brooklyn, spent a recent afternoon turning over half-ton rocks as a Trail Conference volunteer, seemingly oblivious to what lay beneath.

“At work my exercise is this,” Mr. Yu said, wiggling his fingers as if typing. The steps made from those rocks will probably last “at least my lifetime,” he said proudly, whereas after a day at the gym all you have to show are “sweaty clothes.”

Nearly 3,000 hours of volunteer labor by people like Mr. Yu went into building the Appalachian Way, a 1,777-foot-long trail segment 11 miles from Breakneck. Meticulously designed by Mr. Mickelson, it required jack-hammering bedrock and laying 27 stone steps.

“It takes me three minutes to walk by something it took two weeks to build,” mused Mr. Mickelson.

Volunteer Kevin Stamey, 60, a former systems analyst for Goldman Sachs, is also struck by the longevity of trail work. The infrastructure he built at Goldman is gone, he said, upgraded beyond recognition, but his trails could last 100 years.

“The permanence gives you an emotional stake,” he said.

DETROIT—Joe Heaney often feels like a character from Alfred Hitchcock’s “The Birds.”

As a tugboat captain for Great Lakes Towing, his job is to help freighters navigate the swift currents and low bridges of the Detroit and Rouge rivers. But from April to July, it is a struggle just to manage his own dock amid the flocks of ring-billed gulls that annually descend on his workplace.

“They’re chirping at you, their mouths are bright red, and they’ve got those eyes that’ll look right through you,” he says. “And every one of them is upset that you’re in their home.”

Mr. Heaney remembers when this stretch of waterfront was occupied by the Detroit Marine Terminal. He used to tow ships to the terminal, long abandoned. Now gulls nest where cargo and gantry cranes stood, and wheeling birds have replaced bustling stevedores.

“It’s like National Geographic right there on our working dock,” says Lindsay Dew, Great Lakes’ director of operations and compliance.

On a recent Saturday afternoon Mr. Heaney, 59 years old, looks across the 300 feet of concrete dock standing between him and his tug, Wyoming. The pavement is layered with bones and guano. Eggs sit on bare ground, ringed by feathers and grass. The air smells sharply of ammonia.

Acting engineer Scott Rosseel, 32, is the first to attempt the gull gantlet, flapping his arms as he stalks to the boat. Mr. Heaney and deck hand Jeff Davis, 62, follow, baseball caps pulled low. All three tiptoe with eyes on the ground, taking care to avoid eggs. As they advance, chicks hop away frantically and enraged parents screech warnings from the air and commence divebombing.

“You keep agitating them,” Mr. Davis scolds Mr. Rosseel. “Be one with the gull.” Mr. Rosseel’s approach is rewarded with several white splotches on his blue work shirt.

When they finally reach the red and green tug, Mr. Heaney says, “it is completely whitewashed with guano.” Mr. Davis makes a pot of coffee, then grabs paper towels and Windex to clean droppings off the windows. About 20 birds stand on the 86-year-old boat. A nest in the bow contains two brown-speckled blue eggs.

The gulls are a stubborn lot. And it is illegal to kill them; even their feathers are protected under the Migratory Bird Treaty Act. But for all the annoyance, crew members have grown protective of the gulls.

“Cutest little fuzz-ball chicks you ever did see,” says Mr. Heaney. “There’s 10 thousand gulls if there’s one.”

Jay Downen is port representative for Great Lakes Towing, which owns the tugs. He stopped mowing the weeds on the dock because he didn’t want to harm the fist-size gray chicks nestled in them. He also marvels at the birds’ pluck.

“One morning you do a tow, come back six hours later, and there are new nests on the dock,” he says. “They’ll nest on bumpers, towlines, navigation lights. They’ll take anything to make a nest: plants, string, wire, bits of line.”

When called to work at the Detroit dock during gull season, the crew knows to park their cars under a protective carport. They keep a broom handy for the Fleet Captain to shoo birds away when he visits.

The dock’s location is ideal—near the confluence of the Detroit and Rouge rivers, in the industrialized “downriver” area where most freighters call.

According to Robert Burns of the Detroit Riverkeeper Program, part of a national water-quality group, the gull colony had been on Fighting Island in the Detroit River for decades until the landscape became overgrown. It moved to nearby Nicholson shipyard, where employees got rid of it by building a house for a family of neighborhood foxes.

Around 2012 the gull colony found its current home, conveniently located across the street from 9300 W. Jefferson Ave.—a 123-acre wastewater treatment plant. There, the gulls dine on algae and scum skimmed off the open-air tanks.

The opportunistic water birds will eat almost anything—fish, frogs, garbage, crops. “You name it,” says Greg Norwood, biologist at the Detroit River International Wildlife Refuge. “They protect their colony via the benefits of nesting en masse.”

The noise from the Jefferson Avenue colony is constant, anxiety-inducing, and loud enough to prevent conversation below a yell. Casting off, Mr. Heaney pulls a lever to sound the tug’s horn. The gulls bolt en masse into the air. “It looks like the whole earth rises up,” says Mr. Downen.

The captain steers Wyoming down the Rouge and into the Detroit River to meet Sea Eagle II, an integrated tug and barge that carries cement. One additional passenger, too young to fly away, runs laps around the pilothouse, passing the open door at regular intervals.

Mr. Downen watches a gull sitting mockingly on a plastic owl—a faux figure that often frightens birds away. “These Detroit seagulls don’t get scared by much,” he says. Last year he tried using something called a Bird Xpeller Pro, a squawk box that imitates seagulls in distress and birds of prey. Mr. Heaney says it may as well play Frank Sinatra or “mood music,” because the noise only seemed to encourage the gulls, which average three clutches a season.

At the dock, the gulls settle back down, oblivious to the humans and their boats. “[The crew is] trying to find that equilibrium, to not harm the birds and do their jobs,” says Mr. Dew.

The gull situation definitely requires extra manpower, he says—like time spent cleaning the tugs. For an image-oriented company like his, Mr. Dew says, it is “embarrassing” to be seen with guano-covered boats.

One day, in July or early August, the birds will disappear—heading south to spend the winter along the coast from Florida to the Mississippi River Delta. Until then, says Mr. Dew, the problem “is somewhat insurmountable.”

But he’s resigned: “It would be easier to move the dock than get the birds to leave.”

BRIMFIELD, Mass.—Three times a year, traffic on U.S. Route 20, the main street of this sleepy New England hamlet, resembles rush hour in Los Angeles or New York. Motels switch on “no vacancy” signs as people from around the world come to shop at the Brimfield Outdoor Antiques & Collectibles show, one of America’s largest flea markets. But how do you get a carousel horse across a crowded field to your car a half-mile away?

Order a porter.

The porter industry has grown up haphazardly beside the Brimfield show, which happens every May, July, and September. Typically, guys with “porter” scrawled in permanent marker across their white T-shirts wander the show offering to carry finds for a fee. But a new generation of schleppers is getting organized.

“We’re selling a branded service, like Uber,” said 26-year-old Kyle Quinn, CFO and COO of Speedy Porters, that operates at Brimfield. The brand has a lot to do with its shirts: neon orange, with “Speedy Porters” and a phone number screen-printed on the back. CEO Evan Genereux, 25, has been ferrying things around the loosely organized chaos of the show since he was 10 years old.

Porters charge by the hour, distance, or job. Speedy might charge $70 for a job a Sharpie-shirted porter would do for $10, but Speedy has had no luck getting porters to stop undercutting one another. “I saw a dealer try to pay a man with a wooden duck,” Mr. Quinn said.

He says his 10 porters can each make $200 a day during the show.

To prepare, Mr. Genereux has prospective porters complete a timed obstacle course, carrying furniture around the second floor of his parents’ antique store, up and down stairs, then outside to a waiting truck.

Speedy’s business spiked last year when it was the only porter on the Brimfield Flea Finder app. But Ryan Servant, the app’s creator, said he has no intention of giving Speedy a monopoly. There is plenty of competition from porters like the New England Movers, the Porter Johns (four guys named John), and Bob the Porter King.

A decade-and-a-half of scrambling around the show has earned Mr. Genereux the trust of dealers and buyers. Rosa Szule and Michael Walter routinely hire Speedy to collect what they purchase for Lexington Gardens, their Manhattan store.

Armed with a tattered envelope of receipts, Mr. Genereux and his vice president, James Elias, 24, hustled off into the beating sun to make pickups. They each pulled a four-wheeled cart full of bungee cords and packing blankets.

Mr. Quinn, clipboard in hand, took calls and dispatched remaining porters via walkie-talkie from the cab of a small box truck. When not portering, he works as a finish carpenter and professional videogame player. Mr. Genereux is a roofer.

The Brimfield show stretches across roughly 80 acres and to make a delivery, porters must navigate their fragile loads among indecisive shoppers, frantic dealers, and scattershot booths until they reach U.S. Route 20. Then they often maneuver a mile or more down the shoulder to a parking lot, trying to avoid bicycles, wagons, and rubbernecking tourists. One Speedy porter said the only place he had seen anything like it was in El Salvador, where his family was from.

Suddenly, Mr. Quinn’s walkie-talkie crackled with trouble. Was it a stone dog or frog for Lexington Gardens at Booth B24? Where was B24, anyway?

Finding a stone dog or frog in one of almost 6,000 booths, in 21 fields, through tens of thousands of people, is as difficult as it sounds. The Brimfield show has no central organization. Each field has its own rules and most don’t have named or numbered roads. After much backtracking, the two porters were sweating and a little frazzled.

Having temporarily given up on the stone animal, Mr. Genereux and Mr. Elias found Booth B52 and retrieved a 7-foot iron trellis, toy wooden boat, painted child’s chair, small fan, and watering can for Lexington Gardens. At B55 they grabbed a whale weather vane and an armillary, and strapped those down, too.

They would have to come back for the stone animal and a piece described as a “strawberry chandelier.”

In another field, sitting under a tree, Glenn “Red” Lowell was having a more relaxed day. At 29, he is one of Brimfield’s veteran porters. When not moving things, he works as a handyman and welder.

Working six or seven days straight, 14 hours a day, Mr. Lowell says he can make up to $5,000 per show. “I like learning about the antiques, and being able to at least touch and see something I could never afford.”

He says he has been around long enough that clients call him. “Speedy is trying to go more professional, more businesslike than me,” he said. “You could call the way I do it primitive. I’ve got more years under my belt, so I know I don’t need to run.”

Elsewhere, Speedy porters were hopping-to, doing 60 other jobs—moving a ship’s wheel, unloading an 1880s rowing machine. “The porters are a really valuable part of the whole thing,” said Ms. Szule, of Lexington Gardens. Without them, the buying trip would be nearly impossible, “just physically and time-wise.”

Andrew McNally, 36, has staked out a white-gloves niche, moving things like Tiffany and Frank Lloyd Wright glass. “I came up here when I was 12,” he said. “A guy asked me if I would move four bureaus and he gave me $200. I haven’t missed a show for 25 years.”

He is a favorite porter of Fred T. Parks, who deals in late-19th century decorative arts. “When I pick up something with Andy on the other end, it’s music, it just flows,” he said.

During a lull, Mr. McNally admired a sleek 1960s airplane model in Mr. Parks’ booth. Mr. Parks presented it as a gift, and the porter portered his find home.

CHICAGO—After careful consideration, Tyler Keillor made a decision: T. rex had lips. In the debate over dinosaurs’ “oral margin,” one of the country’s top paleoartists has taken sides. Mr. Keillor’s job is to create “flesh models” of dinosaurs and other prehistoric animals based on fossil evidence—giving creatures that died millions of years ago a face, a story and sometimes lips.

Using traditional mediums like clay and resin, as well as CT scanning and 3-D printing, he is at the forefront of incorporating digital art and technology into paleontology.

Mr. Keillor works at the University of Chicago Fossil Lab under celebrity paleontologist Paul Sereno. His work, found in museum collections around the world, is often the public’s first look at a newly discovered species, as with the pebbly-faced predator Rugops primus, which was unveiled in 2004. “A plain fossil doesn’t look like a heck of a lot to the average person,” Mr. Keillor says.

Instead of studying science, he cut his teeth working in a dental laboratory, doing special-effects makeup and studying wig making at Chicago’s Lyric Opera. As a child, he “would try to make little puppets of the alien from ‘Alien,’ ” he says. He dropped out of college to work on low-budget horror movies, commercials and stage productions.

His skill set was well-suited to Dr. Sereno’s team. After another paleoartist struggled with the hair of a “7,000-year-old beautiful woman,” Dr. Sereno says, he turned her over to Mr. Keillor. “When you see it in the ground in the field, you need to have the mind and eye of an artist,” he says. “Paleontology is about envisioning things and bringing them back to life.”

On a recent Thursday, the soft-spoken Mr. Keillor, 42 years old, was painting orange silicone over pieces of a 95-million-year-old rib, the last of about 100 Spinosaurus bones he was reproducing for the University of Chicago before it repatriated the originals back to Morocco.

The Sereno team’s work on Spinosaurus, a carnivorous, semiaquatic theropod, was detailed in the recent Nova film “Bigger Than T. rex.” Among other reasons, the project is exceptional for being the first life-size skeleton produced from a three-dimensional digital model. Different sets of bones were scanned, resized and arranged to make a complete digital skeleton, with Mr. Keillor and the paleontologists filling in any missing bones using what Mr. Keillor calls “informed speculation.”

A computerized mill then cut the bones out of foam, which were molded and cast in resin. The 50-foot skeleton was mounted for exhibition in a swimming pose. Acme Design Inc., in Elgin, Ill., made the 5-foot skull. “It’s pretty wild, making something really old using new technology,” says Acme founder Clint Borucki.

The Fossil Lab’s next project involves 3-D printing the articulated, mountable skeleton of a birdlike dinosaur from CT-scanned fossils, which has never been done before.

Mostly, however, Mr. Keillor’s artistic decisions come from fossils and from studying dinosaurs’ nearest living relatives: reptiles and birds. He decided to give his Heterodontosaurus a fleshy protuberance over its nose like a turkey because of an indentation in the fossil skull. He also gave it a beak, fangs, molars, cheeks and fiendish-looking eyes. But he is quick to point out, “There’s a bone above the eye that makes it look evil. It’s not me, it’s the bone.”

Much of a paleoartist’s work is determining textures, colors and tissues not preserved, or barely preserved, in the fossil record. “I have to be able to justify every choice, every millimeter of the sculpture,” Mr. Keillor says. He concedes that he is willing to find “a feasible way to make the thing more visually interesting.”

His boss is emphatic about seeing “the balance and the beauty” in the animals his lab animates. (Dr. Sereno himself was named one of People Magazine’s 50 Most Beautiful People in 1997.)

“Usually, I give my dinosaurs lips,” Mr. Keillor says. “An animal living in an arid terrestrial climate would have had lips,” he reasons, pointing to carnivorous reptiles like Komodo dragons as living examples. But the oral margin remains controversial.

Thomas Carr, director of the Carthage Institute of Paleontology at Carthage College in Kenosha, Wis., is staunchly opposed. “If artists put lips on a dinosaur reconstruction I know that they’re doing so without any evidence to support that idea,” he says, “They’re simply not playing by the rules of rigor.” Dr. Carr considers birds and crocodiles, who are lipless, to be the only acceptable living references for dinosaur features. Reptiles like Komodo dragons are too distantly related, he says, “Dinosaurs are interesting enough that they don’t need to be sexed up.”

But Dr. Carr is a fan of showing dinosaurs in nontraditional poses, like the hulking yet subtle Dryptosaurus Mr. Keillor did for the Lake County Discovery Museum in Wauconda, Ill. It is a departure from what Mr. Keillor calls the “running, roaring cliché.” He portrayed it with eyes narrowed and mouth almost shut. “It looked like it was thinking,” he explains. He wants viewers to wonder, “Is this thing satiated and calmly looking at me, or is it about to eat me?”

While trying to decide on the proper skin for Rugops primus, which Dr. Sereno discovered in Niger, Mr. Keillor read technical papers about the animal’s nearest relative. He concluded that the texture was “an almost perfect match for a bag of dry lentils.” So he fashioned the creature’s pebbled, scaly skin out of lentils pressed into clay. For the skin of a little head-butting dinosaur, which is so new it has yet to be named, he used impressions from dried avocado skins.

“Tyler has a level of exacting detail and creativity that’s really remarkable,” Dr. Sereno says. Adds Mr. Borucki, of Acme Design, “You expect it to breathe, to blink.”

Whenever Mr. Keillor needs encouragement, he can turn to the roommates who inhabit the basement of his suburban Chicago home. Posed in a semicircle are nine cave man sculptures from the 1930s, discarded when Chicago’s Field Museum, where Mr. Keillor once worked, eliminated its beloved “Hall of Man” exhibit.

Details like the bloody knuckles on one of the cave men have a visceral narrative quality Mr. Keillor brings to his own work. The Keillors’ own 4-year-old son, meanwhile, prefers to stay upstairs.

“It’s like a painter owning a van Gogh,” says Tyler’s wife, Kari. “They’re part of the family.” Mr. Keillor took them to be appraised on the popular TV series “Antiques Roadshow,” but the experts didn’t see a market for 5-foot plaster Neanderthals. “I paid $75 each for the large statues, and I have a child that I paid $25 for,” he says. “I think I got a great deal.” When he has time, he plans to construct “a little bit of cave wall and a prop campfire with flickering lights so they’ll feel more at home.”

Lips aside, “He’s one of the best sculptors out there,” says Dr. Carr, who considers Mr. Keillor a master of realistic painting and scales. “Tyler has little competition at the present time,” he adds.

An example is his baby sauropod, just hatched from its egg, about to be eaten by a snake. Mr. Keillor made the diorama for the University of Michigan and is marketing a miniaturized version of it in “Prehistoric Times” magazine. The scene, discovered by paleontologist Jeff Wilson, was preserved in one fossilized moment. “I followed the bones and did what they told me to do,” says Mr. Keillor. Yet the pathos on the face of the little green sauropod is enough to melt the most rigorous of hearts.

CHICOPEE, Mass.— John Barrett decided to gather a little printing intelligence. “Have you seen any interest in, or need for, hashtags?” he asked a customer he was showing around Letterpress Things, his 6,500-square-foot store in a former paper warehouse in Chicopee, Mass.

Mr. Barrett’s company is proof that in the digital age, there is still some cachet in things done the old-fashioned way. His customers still set type by hand, often using antique type and equipment salvaged from old print shops. But the rising demand for symbols like @ and # in today’s communications has created problems—and some opportunities—for lovers of this centuries-old medium.

Letterpress is the process of printing type and graphics from an inked, raised surface—the method used in ancient Chinese scrolls, Gutenberg’s Bible, and printed matter until it was slowly replaced by photomechanical reproduction over the course of the 20th century. Today’s letterpress printers prefer the era of movable type, in which each letter or character is made individually out of wood or metal.

Mr. Barrett, 73 years old, a former adman for Strathmore Paper, began getting requests from customers who wanted to add the # to their personal stationery, business cards, or invitations. He realized that what had been known as a number sign or pound sign could be repositioned and sold as a hashtag. Capitalizing on the trend, he ordered a variety of sizes to sell at a wayzgoose, or printers fair, in San Jose, Calif.

“Lo and behold, I did sell one bag,” he says. He has since sold eight or 10.

“It used to be, no one ever wanted any of that stuff,” says Edward Rayher, whose type foundry, Swamp Press, in Northfield, Mass., produced the pieces of metal type for Mr. Barrett’s hashtag kits. “The ‘at’ signs came first,” about 10 years ago, he says. “This was the first time that we’ve ever done the hashtags.”

A sophisticated dealer in this expanding marketplace is Patrick Reagh, 66, a veteran printer in Sebastopol, Calif. He began by selling packages of “at” signs under the label P@’s @s, which he sells on eBay. “I’m surprised they’ve actually sold quite well,” he says. Now he, too, has crossed over into hashtags. He says his smartly packaged product, at $42 a box, is “as they say: #great bargain.”

In his recent book “Shady Characters: The Secret Life of Punctuation, Symbols & Other Typographical Marks”, Keith Houston notes that the number sign, or pound sign, is derived from the abbreviation “lb,” in Latin libra pondo. Libra means scales or balance, pondo means to weigh. Sometime in the late 14th century, “lb” acquired a line drawn above the middle of the letters (a typeset example dates to 1698).

Eventually, lb with a line became #. The symbol’s ascension began in 1968 when it was selected for the touch-tone keypad, designed by John E. Karlin, an industrial psychologist at Bell Labs. The symbol would have been familiar to users from typewriter keyboards, and was selected, along with the asterisk (*) or star. Then, in 2007, the pound sign was adopted as a way of grouping messages by Twitter, the online social-networking service.

Bryan Baker, 36, is the printer-in-residence at Signal-Return letterpress studio in Detroit. He uses his @ symbols so often for printed email addresses, they wear out quickly. Printers in the same boat will sometimes replace the @ with a dingbat, a printer’s ornament absent from a standard keyboard but found in abundance in collections of old type. They can get away with it, Mr. Baker explains, because people don’t really see the @ anymore. He has seen stars, bullets, triangles, fleurs-de-lis and even little turkeys used as stand-ins. Another solution is to spell out the word “at.”

In a strange way, the limitations of hand-set type often yield more exciting, innovative designs. “It’s harder to be derivative,” says Mr. Baker, because the first easy solution isn’t always available as it would be on a computer.

“There is something magical, almost mystical, in creating the printed word,” says Mr. Barrett of Letterpress Things, “When a person sees something that has been letterpress printed there’s a dimensionalism there, there’s a depth. You’re not just seeing a flat surface like a page out of a magazine, you are now…looking into a space.”

 

IN ONE OF the latest revivals of all things old-timey, more millennial New Yorkers are choosing to spend their Friday and Saturday nights sober and dancing in circles with strangers.

Their discovery: the centuries-old tradition of contra dancing.

Derived from English country dancing—think of the long paired lines of couples crisscrossing and partner-swapping in all those Jane Austen country-manor balls, now press fast forward—contra offers young urbanites an inclusive atmosphere where they can work up a little sweat away from the gym and touch human beings instead of screens.

At Brooklyn Contra, held at an unglitzy gym in Park Slope, Friday night dances have become so popular that its volunteer organizers recently added a second monthly event to the schedule. They are also helping set up new contra dances in Crown Heights and on Staten Island, they said.

One organizer, Avia Moore, 32 years old, said contra dancing’s homey, welcoming aura provides a community many of her peers are looking for. “New York can be so isolating,” she said.

David Chandler, 74, a longtime dancer and board member of Country Dance New York, which has hosted a contra dance in Greenwich Village for 50 years, said, “A new generation is really taking responsibility for contra dancing now—not just participating.”

For those more accustomed to socializing in dark clubs with exotic cocktails and pounding music, contra’s wholesome, folksy culture can come as a bit of a shock.

“The first thing I thought when I walked in the door is, where is the bar?” said Dakota Kim, 34, an event producer who recently attended her first contra dance in Brooklyn. “But then it’s so fun you don’t care.”

On the dance floor, partners start out facing each other in long lines while a live band plays jigs and reels. With the cadences of a comforting auctioneer, the caller calls out moves to dancers on the floor. Partners clasp hands, spin and look into each other’s eyes.

Traditionally the idea is to interact with everyone on the floor and say yes when anyone asks you to dance.

And while the new contra aficionados are adhering to some traditions, like no booze, they are adapting others—like requesting new, higher-energy dances.

“I call it my running instead of actually running,” said 23-year-old Shannon Sullivan. “I’d rather spend $12 on an entire night of fun than on a couple drinks and no guarantee of having a good time.”

Not everyone likes the changes. Dudley Laufman, 84, of Canterbury, N.H., said the faster, more complicated pace of what he calls “modern urban contra” leaves no time for courting. “The nature of the dance itself has changed,” said Mr. Laufman, one of the few remaining fiddler-callers, widely credited with popularizing contra dancing in the U.S. beginning in the 1970s.

“Courtship and camaraderie is always what the dance has been about”—not a workout, he said.

Historically, while the wig-wearing gentry held contra dances in private ballrooms, the working class had them in their farmhouses.

“You would clean out the furniture from the house, and the fiddler, who would also be the caller, would sit in the sink,” said dance historian and caller David Millstone, 68.

Ms. Moore and fellow organizer Joe Rinehart, 35, a couple who met while contra dancing, deliberately market their dance to Brooklynites with a taste for the old-timey. On this night they look the part in a vintage dress and newsboy hat, respectively.

Diane Stephenson, 31, was a newcomer to the Friday dance. “Normally you don’t touch strangers, you don’t get that close to strangers and look them in the eye for extended periods,” she said.

“I don’t know what it is about the space,” said Ms. Stephenson, who works for a software company. “But it makes it feel OK.”

While the contra ethos maintains that anyone off the street is welcomed and taught to dance on the spot, it can be difficult to maintain a consistently safe space in an art form based on touching strangers.

On the rare occasions when renowned local dance caller Bob Isaacs sees inappropriate touching or partnering, he said he works with organizers to quietly pilot the offender off the floor.

But as contra’s youthful adopters take charge of the community, one convention is undergoing a change. “People, especially women, should be able to refuse a dance,” said Maia McCormick, a 21-year-old Manhattanite and up-and-coming caller.

Another change lies with the historical terms for partners—traditionally called “ladies” and “gents.” These days, when Mr. Isaacs introduces the dance, he says, “ladies and gents is a dance role, not a gender.”

In Brooklyn, the caller announced that instead of “gents” and “ladies,” he would be saying “jets” and “rubies” because some dancers have asked for genderless terms.

Whatever names are used, “it’s a fantastic way to meet people,” said Ms. Moore. “It can be flirty but safe.”

After the recent dance, she and Mr. Rinehart exchanged a high-five as they tallied up attendance: 95 returning dancers and 20 first-timers.

One of those newcomers was Eileen Regan, 30, who works at a winery. The dancing was fun, but she said she couldn’t help thinking “how much money we could be making if we set up a Jell-O shot booth here.”

THE PHOTOS on Jay Downen’s cellphone have an unusual commonality: The subjects are all shot from the perspective of a boat.

It is a fitting distinction for someone who has spent more than three decades working on the water—and who currently commutes halfway across the country to help ensure that one vessel, in particular, is shipshape for its 30 daily New York Harbor crossings.

“I took a pay cut to come out here,” said Mr. Downen, 53 years old, who serves as chief engineer of the 178-foot, 516-ton Lt. Samuel S. Coursen—also known as the Governors Island Ferry. “It’s something different.”

Governors Island, a former military outpost and U.S. national park that serves as a seasonal arts venue with a spectacular lower Manhattan view, draws a diverse summer crowd. In particular, said Mr. Downen, the variety of people ferrying to the island’s events—from a Jazz Age Lawn Party to the hip-hop extravaganza Rock the Bells—offers an interesting passenger mix.

During the off season, which began in late September, the Coursen still traverses the quarter-mile of New York Harbor—an eight-minute run—but only for New York Parks Department employees, contractors, students and instructors from the New York Harbor School and various dignitaries.

Mr. Downen, an employee of HMS Global Maritime Inc., the company that operates the Governors Island ferry, drives 10 hours from his home near Detroit to New York City every two weeks. In his red Ford F150, loaded with $400 worth of groceries he drives straight from the Holland Tunnel down the West Side Highway and onto the ferry.

Below the passenger and car decks, the noise in the vessel’s engine room—Mr. Downen’s stamping grounds—is oppressive, which is why he is seldom seen without noise-canceling earmuffs. The two massive yellow engines are his primary responsibility.

“I monitor everything: maintain all the machinery, rebuilds, dry docks, whatever needs to be done,” he says over the din.

His office, a narrow air-conditioned space off the engine room, is crammed with dials and gauges. With a pot of coffee and a large jar of Dum-Dums lollipops, he watches over the boat’s vital systems: propulsion, generators, hydraulics, not to mention the structural integrity and seaworthiness of the vessel.

Steve Caputo, general manager for HMS Ferries, a division of HMS Maritime, said he recruited the Michigan engineer, in part, because of his three-plus decades in the maritime towing industry, where people are “the most creative and most resourceful.”

Plus, he added, “Jay’s just an excellent engineer.”

Together with his shipmates, Mr. Downen works two weeks on, two weeks off, in rotation with another crew. After 14 12- to 14-hour days, he heads back to Southgate, Mich., to be with his wife Dawn, whom he calls “Mama.”

While on duty, the crews live on Governors Island, its sole inhabitants, in dwellings built for the military and Coast Guard officers who ran the island until 1996. Mr. Downen lives in a blockhouse where Ulysses S. Grant is once said to have stayed, in accommodations many Manhattanites would covet—with DirecTV, 16-foot ceilings and a private bathroom (a privilege of rank).

“I’m a master of crock pot cooking,” says Mr. Downen, who shares his groceries with Spencer Crow, 20, his oiler. Their favorites: chicken and pot roast.

After dinner the chief engineer has time for laundry, a phone call to Mama, and a shower. He says, “By 10 o’clock it’s past my bedtime.”

For her part, Ms. Downen says it is hard having her husband home and then gone again. He has missed the last two Christmases and Thanksgivings, but will be home for them this year.

“Out there on the water, anything can happen,” she said.

In two years since he began the job, Mr. Downen hasn’t taken time to explore the glittering city that, from the island, can sometimes seems close enough to reach out and touch.

But, he said, “One of these days I’m going to take a long weekend when Mama is here and I’m going to check it out.”

Most of the time, though, he said, “I can’t get off the boat”—since the Coursen can’t sail without a chief engineer. When it docks on Governors Island for the night the crew stays with it.

A member of the International Organization of Masters, Mates & Pilots, a seafaring union, the Wisconsin-born Mr. Downen has worked on boats since he was 17 years old.

Island life isn’t so different from the lighthouses he lived in as a child, he said, when his father was in the U.S. Coast Guard.

And the seagoing life continues to be a family affair.

Mr. Downen’s only son, also named Jay, is working his way up into a career in maritime engineering. “We’re old school,” said Mr. Downen, who said he never attended college after starting on a boat right out of high school.

“We come up through the hawse pipe,” a fitting where an anchor chain enters a boat, and an access point for stowaways. In educational terms, it is the opposite of a maritime academy, he said.

His wife said she had other ideas: She wanted their son to be an accountant. He tried the 9 to 5 life, she said, but she eventually realized it wasn’t going to eclipse the siren call of the sea. “It’s in the blood.”

THESE BOATS are made for human-waste trafficking.

On Nov. 25 the city christened three new sludge boats, the vessels used to transport the refined sewage of wastewater treatment facilities, including the onion-domed plant on Newtown Creek in Greenpoint. The sludge that gives the watercraft their name is one of two byproducts of the sewage treatment process, the other being water. The new boats, costing $106 million altogether, are necessary because New York’s toilets are always flushing.

“The sludge never stops,” said Gordon Arnold, captain of the Port Richmond, one of the new boats.

To get a picture of what the sludge boats do in relation to sewage plants, imagine a drinking glass placed under a pitcher that is always pouring liquid, Arnold said.

“When that glass is full, you better have another glass there in a hurry,” he said.

When a boat is late, the city has a “sludge emergency,” Arnold added, though he declined to elaborate.

The Port Richmond and her fellow fleet members the Rockaway, and the Hunt’s Point, come custom-designed to navigate the shallow waters of Newtown Creek and the low clearance of the Pulaski Bridge. The city is decommissioning two older boats and keeping another, so the fleet will soon total four. Each of the new vessels takes six people to operate and can carry as many as a million gallons of muck.

Unlike their predecessors, the new boats can load sludge directly from the Newtown Creek Wastewater Treatment Plant, nearly a mile upstream at the end of Humboldt Street. The old boats stopped at the mouth of the fetid inlet to drain an 800,000-gallon storage tank on shore, connected by pipeline to the plant. Now the tank, at the foot of Dupont Street, has been dismantled to make way for the Greenpoint Landing mega-development and an expansion of Newtown Barge Park.

The Department of Environmental Protection estimates that its boats transport 1.2 billion gallons of sludge each year. Of the city’s 14 wastewater treatment plants, eight are equipped to separate the liquid in the sludge from the solid, a process known as dewatering. The other six plants must ship their goop to those eight. Newtown Creek’s plant is the biggest in the city, with sewage coming in from more than a million people in Williamsburg, Bushwick, Bedford-Stuyvesant, Greenpoint, and lower Manhattan. It does not dewater, so its sludge gets shipped to Wards Island.

At Wards Island the goop goes into a centrifuge, where it is spun until the separation occurs. The solid, a black-dirt-like substance called “cake,” is handed off to a private contractor for disposal, in landfills and in abandoned mines in Pennsylvania. The nitrogen-rich liquid, or centrate, is eventually released as clean water.

The city used to dump the sludge in the ocean, 12 miles offshore, according to Arnold, until Congress banned the practice in 1988. For many years afterwards, the city turned the dried-up dung into fertilizer, but it recently decided the effort was too expensive.

Today, getting rid of the cake costs the city $73 to $77 per ton.

The new boats were partly covered by a federal stimulus grant, but the cost of wastewater treatment is passed on to consumers by way of their water bill.

According to the department’s deputy commissioner for design and construction, the new boats are going into service just in time.

“We’re getting ready for the busiest day of the year,” Vincent Sapienza said, “Black Friday.”