Kate Winslet, left, and Saoirse Ronan in “Ammonite.” Neon

In “Ammonite,” Kate Winslet plays Mary Anning, the English paleontologist whose ramblings along the West Dorset coast in the 19th century yielded a wealth of fossilized treasures, including bones from the Jurassic-era Ichthyosaurus. She sold her discoveries in her Lyme Regis shop and is said to have inspired the classic tongue-twister, “She sells seashells by the seashore.”

In Francis Lee’s sometimes dubiously speculative retelling of Anning’s life, that’s not all she did. In this alternately dreary and dramatically juiced-up interpretive history, Lee proposes that Anning embarked on a torrid affair with Charlotte Murchison (Saoirse Ronan), her real-life friend and fellow explorer. Lee’s defense of that artistic license is that there is no documentation of a love affair in Anning’s life, but there are plenty of passionate female friendships, which could indicate a buried queer history.

In “Ammonite,” Murchison and Anning evolve from frosty acquaintances to tentative friends, then mentor and protege and finally to lovers. Those scenes – graphic, expressive and unabashedly carnal – provide explosions of heat in an otherwise chilly and dutifully dull period piece that will remind some viewers of last year’s “Portrait of a Lady on Fire,” without the bold visual style.

Draping his actors in the blues, chalky whites and grays of the environment, Lee goes out of his way to emphasize the dour quietude of Anning’s life, spent either on the beach in windswept solitude or in the pinched company of her mother (Gemma Jones). It’s a joyless existence, one not much brightened by the arrival of Roderick Murchison (James McArdle) and his neurasthenic wife. When Charlotte is left behind while Murchison goes on a trip, the cosseted married lady finds freedom with Anning who, embittered by being closed out of the male, upper-class scientific establishment, couldn’t care less about social approval or Victorian niceties.

Like the artifacts Anning digs up and dusts off, “Ammonite” possesses a singular beauty, one that reflects her own obstinate refusal to please. In tone, pacing and focus, it stays true to its principles of making the audience meet it more than halfway. Those who do will be rewarded by fine performances from Winslet and Ronan, who develop a credible chemistry despite the fact that it’s probably hokum. Lee might think that confecting a sexual relationship between the two makes their story transgressive, but what would have been genuinely revolutionary would have been to honor the record of Anning’s story, including her intrepid curiosity, the workings of her scientific mind, her independence and, yes, her friendships, whether they involved romance or not.

Those forces wind up muted in a story that, for all its subversive speculation, winds up feeling trite and tame. Rather than a movie that breaks the mold, it looks like Anning has inspired one we’ve seen before. In a delightful article about Anning in the Smithsonian last summer, the science writer Riley Black quoted one of Anning’s letters: “The world has used me so unkindly, I fear it has made me suspicious of everyone.” She had her reasons.