SUTTON — One hand on her hip and another propped on a trailside tree, Sarah McManus, 30, made a declaration.
“I feel a little deceived,” she told her sister, Caitlin.
The two women were promised a tranquil morning stroll through the woods. Gentle slopes. A clear dirt path. Maybe an unassuming hill to scale.
What they got was more rock-climbing expedition than ramble. Caitlin’s fiance had brought the sisters to Purgatory Chasm State Reservation, the rocky outcrop tacked off Route 146 just south of Worcester. They spent the morning scrambling through the quarry, balancing on jagged rock edges, sliding down vast stone faces, and leaping off granite boulders.
“We thought it would be a little more relaxed,” admitted Caitlin.
It was a spot-on assessment of the park’s rough-and-tumble reputation.
“Purgatory Chasm is a bold and unique landscape,” proclaims the sign, which describes the park’s “slippery and deceiving rocks.” “Hikers beware of the dangers of this trail.”
On Thursday, the chasm drew dozens of visitors, mostly locals, seeking to enjoy one of the last days of August. The park, established in 1919, features jutting rock faces and hidden caverns that delight hikers with names like Devil's Coffin, Lover’s Leap, and Fat Man’s Misery — a narrow slice through two sheer rock faces that is only passable on an empty stomach.
Within the chasm, which stretches about one-quarter mile, wisps of blue paint provide guidance on the best way to navigate the wide swath of rocks, but they’re only suggestions: They’re probably your best bet, but no guarantees.
“I like that it’s a different kind of hike,” said Shawna Salomon, 32, of Auburn, as she watched her 3-year-old son jettison himself from one rock to another. “It’s not just dirt and sticks.”
“It’s kind of a choose-your-own-adventure hike,” said her husband, Michael.
Mark Troy, 50, of Braintree, had an even more evocative metaphor. “It’s like a Reeses,” he concluded. “You can do it any way you want.”
According to a sign in the visitors center, the chasm likely originated from huge rocks carried inside a massive glacier that were deposited in their current spot when the glacier melted at the end of the last Ice Age about 14,000 years ago.
Now, the reservation is a prime spot for families, picnickers, and couples seeking a romantic date spot.
Ed Curis, Caitlin McManus’s fiance, was hiking one of the trails surrounding the chasm two weeks ago when he came upon a couple, moments after a proposal, popping open a bottle of champagne in an alcove adjacent to a slow-moving brook.
Cute. But not what he would have chosen for his fiancee, he concluded.
“She wouldn’t have been thrilled to have to hike to a proposal,” Curis said.
The granite outcrop also caters to thrill-seekers like Cindy Marszalkowski, 22, an avid rock-climber and bouldering enthusiast from Providence who has grappled her way up Purgatory Chasm rocks for years. On Thursday, she wasn’t rock-climbing, but just walking barefoot up a steep rock face, her flip-flops in her hand.
“Have you ever tried to climb to the top of that thing?” she asked her boyfriend, Jared Mann, as she pointed at a jagged spear of rock jutting 30 feet in the air, nearly vertical.
“That pointy thing?” asked Mann, 23. He looked incredulous.
“Yeah,” she said, matter-of-fact. “It’s really hard.”
The chasm is not deep in the wilderness — cellphone service remains strong even at its lowest points – but the craggy route is not without its dangers. Two months ago, a 39-year-old Uxbridge man died after he fell from one of the highest points in the park, the eighth death in 136 years at the reservation.
Marissa Massucco of Blackstone kept her two children, Brontë and Liam, low to the ground, warning them to watch their feet while scrambling over the rocks. One of the first families to hit the park in the morning, they picked their way through a trail called Little Purgatory, their German shorthaired pointer leading the way.
TAMIR KALIFA FOR THE BOSTON GLOBE
Cindy Marszalkoski, 22, an avid rock climber, took a picture of her boyfriend as they scaled Purgatory Chasm.
“This is cool,” pronounced Liam, 12.
“We should come here more often,” said Brontë, 7.
“We’re here now,” Massucco said,
“I know,” said Brontë in somber tones, as if already imagining the day’s end. “I’m just saying, we should come here more often.”
For Troy of Braintree, the lover of hikes and Reese’s Peanut Butter Cups, a visit to Purgatory Chasm is an end-of-the-summer tradition. He’s been coming to the quarry for more than 40 years, ever since he was a Cub Scout. Now, he brings his 13-year-old son, Owen.
Owen had his own agenda for the day. Two years ago, he discovered a cave about halfway down the chasm, between the slanted rock and the mossy rock. (At least, he believes he’s the only one who knows about it.) This year, he came prepared with a flashlight for further exploration.
“I like ending my summer like this,” said Owen, after his cave was thoroughly spelunked. “It’s good bonding time with my dad.”
Troy said it’s a favorite time of year for him, too. The funny thing is he knows that these must be the same craggy caverns he scouted and scrutinized when he was a child. But with Owen, he said, it feels like he’s discovering the caves for the first time.
Deceiving rocks, indeed.