The historical Anning made important discoveries that men took credit for, as the film notes in a deft opening sequence, when the skull of an ichthyosaur is put on view in the British Museum. On the display label a male buyer is given credit for its donation, replacing the notation that Mary Anning discovered it. The film picks up with Mary eking out a living with a shop where she sells souvenir fossils to tourists. Winslet makes her stern and brittle but immensely sympathetic, accustomed to disappointment and expecting little more than survival. The contained, potent performance is one of Winslet’s best.
Roderick Murchison (James McArdle), a would-be paleontologist hoping to learn from Mary, arrives with his delicately pretty wife in tow. Charlotte is taciturn for a different reason to Mary’s. We discover through a brief conversation that they have lost a child. “I want my bright, funny, clever wife back,” Roderick complains, signalling the patriarchal privilege and authority that the film never presents heavy-handedly. He pays Mary to look after Charlotte and take her fossil hunting while he is gone. Lee draws the contrast between the brusque, defensive Mary and the sad, timid Charlotte too starkly at first. Charlotte wears ladylike gloves. Mary squats and pees on the beach. But he gets away with it because Winslet and Ronan give their characters hidden depths.
When Charlotte becomes ill and collapses in Mary’s shop, she moves into the cottage and their dance toward romance begins. In reality, Charlotte and Mary became lifelong friends. Lee acknowledges that there is no evidence hinting at a sexual relationship, but for his artistic purposes, those facts don’t matter. Mary and Charlotte not only stand in for women of their era. They are alive on screen as individuals confined by Charlotte’s marriage, by the mores of society, and by their own confusion and reticence.
At times the dialogue is minimal, but the camera captures revealing glances and reactions. When Mary needs salve for the ill Charlotte, she must buy it from Elizabeth Philpot, played by the perfectly cast Fiona Shaw. One longing gaze from Shaw tells us that something intense has happened between Elizabeth and Mary. Winslet’s guarded posture and downcast eyes tell us that it ended badly. That is all we know or need to know at that point, as the film builds its intrigue.
We know, of course, where the relationship between Mary and Charlotte is headed, but not how. With some counterintuitive moves, Lee keeps us guessing about who will make the first tentative advance. A couple of explicit sex scenes leave no doubt about the overpowering, long-thwarted physical attraction between them. But the film gives equal emphasis to how the women change, as Charlotte comes to life and Mary drops her protective shell.
One of Lee’s brilliant choices is to refuse to put a soppy romantic gloss on the affair. He suggests instead that passion can blind lovers to a true understanding of each other as easily as it can open their eyes. Another smart choice was casting the affecting Gemma Jones as Mary’s mother, whose own heart-wrenching story plays out gently. It doesn’t spoil the ending to say that the final image returns to Mary’s discovery in the British Museum, where she and Charlotte look at each other from opposite sides of the glass display case. It is a quiet scene as lovely and as brutally honest as the rest of Ammonite.
And if you liked this story, sign up for the weekly bbc.com features newsletter, called The Essential List. A handpicked selection of stories from BBC Future, Culture, Worklife and Travel, delivered to your inbox every Friday.