Credit: Agatha A. Nitecka/Neon

Rustling petticoats, windswept beaches, two awakened women in love: The bare outlines of Francis Lee's Ammonite — starring Kate Winslet as the real-life 19th-century paleontologist Mary Anning and Saoirse Ronan as the pale-eyed beauty who captures her heart — sound a lot like last year's sensational French import Portrait of a Lady on Fire. (Call it, maybe, Portrait of a Lady on Fossils.)

But Lee's bracing romantic drama is its own fierce animal: a movie nearly as steeped in the wonders of natural world as it is in the emotional lives of its uncommon characters. As the story opens, Winslet's Mary seems easily as flinty and inflexible as her beloved samples — the Jurassic bones and ancient whorls whose imprints she pulls from the stones that line the shores of her native Lyme Regis, England.

Far removed from the clubby, almost entirely male experts in her field, she has little time and even less patience for anything beyond her research and the basic upkeep of the modest home she shares with her elderly mother (played by Harry Potter and Bridget Jones alum Gemma Jones; Killing Eve's Fiona Shaw also has brief but memorable turn as one of Mary's former paramours).

So when an aristocratic dabbler from London (James McArdle) appears on Mary's doorstep, eager to learn more of her work, he brings unwelcome disruption to her daily routines. But he also brings his wife: a lovely, wilting lily named Charlotte (Ronan); the Lyme air will do her "melancholia" good, he believes. And the money he's willing to leave for her care will pay Mary's bills far better than the cheap trinkets she cobbles together for tourists to make ends meet.

There's an austerity to the film — long shots of stone and candlelight, clipped dialogue — that can feel rigorous, almost grim. But Lee (God's Own Country) is only building a richer kind of mood, and priming the canvas for his actresses, who reward that faith with remarkable performances: Winslet, raw-nerved and ferocious beneath her reticence; Ronan a slow-blooming, stealthier force. Much will undoubtedly be made of two explicit love scenes, happening as they do between two famous female movie stars; like its coiled seashell muse, though, Ammonite finds its beauty in the whole, not the parts. A-

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