Film ‘First Cow,’ a western fable of unpasteurized poetry

The American West is about as welltrod territory as there is in movies, but Kelly Reichardt keeps unearthing new treasures.

Her latest excavation, “First Cow,” is her most sublime yet. Like many of Reichardt’s previous films, it’s set in Oregon but in a seemingly unremarkable in-between moment in history. It’s a tale literally dug up. In its opening scenes, a contemporary woman and her dog are walking near a broad river where an oil tanker slowly glides past. The dog sniffs something first, then the woman sets to clawing the dirt away.

Her find can only be mysterious to her; it reveals nothing for posterity or science. Just some eternal truths, and one achingly lovely yarn that reaches, through time and cinema, to today. “First Cow” leaps back to the Oregon Territory of the 1820s, where a pair of aimless and impoverished travelers are brought together by circumstance, kindness and baked goods.

The joys of “First Cow” are many. The thoughtful, unshowy textures of its clothes and surroundings. The fabulous chemistry of its two leads. The softly stirring guitar of William Tyler’s score. All of these details add up to a wholly original western, one with its own rhythms, ideas and iconography. Like previous Reichardt films, its screen is a near-square box, which here doesn’t hem in the normally widescreen landscapes of the West but reorients its focus.

“First Cow” is based on the novel “The Half-Life,” by Jon Raymond, a frequent collaborator of Reichardt’s who wrote the script with her. Though not a household name, Reichardt has long been one of the more celebrated American filmmakers for films (”Old Joy,” “Certain Women,” “Meeks’ Cutoff”) that with a spare, untamed beauty have remapped the Pacific Northwest.

“First Cow,” an A24 release, is rated PG-13

Allyson Riggs / Associated Press Orion Lee, left, and John Magaro in a scene from “First Cow.”