Hunt uncovers lost paintings of a wild west art pioneer

Charles Deas, Sioux Playing Ball, 1843. Lent by the Gilcrease Museum, Tulsa, Oklahoma. Photograph: courtesy of Denver Art Museum

The forgotten works of one of the greatest painters of the wild west are once again capturing the imagination of the American art world at a major exhibition in Denver with their raw, colourful depictions of Native American warriors, fur trappers, rugged settlers and breathtaking scenery.

Charles Deas, a gifted 19th-century artist who captured the essence of the frontier spirit on canvas, died young, locked away in a mental hospital. His works, which had been the toast of New York, were mostly lost and forgotten. Now the Denver Art Museum exhibition, Charles Deas and 1840s America, which opened last weekend, has launched a treasure hunt to track down dozens of lost Deas paintings that could be worth millions.

Art experts, who have scoured America to bring together 39 Deas paintings for the exhibition, have recovered less than half of his known body of work. Records indicate many others could be hidden away in dusty attics, hanging on living-room walls or being sold for a few dollars at garage sales.

"Probably 50 are missing. I am hopeful more of them will show up. A really important work would be worth about a couple of million dollars," said Carol Clark, an art historian who assembled the exhibition.

Clark has spent decades travelling across the US to track down Deas works and co-ordinating the search with others. Paintings have turned up in a remote Nova Scotia fishing village, under a bed in Minneapolis and even hanging on the wall of a St Louis library – attributed to a different artist.

Clark admits that the hunt has been frustrating at times "and really hard work", but she believes it was worth it to rescue the reputation and work of a man who enjoyed a brief but bright flash of popularity in the 1840s before personal tragedy overtook him.

Deas was born in Philadelphia in 1818 into a prominent East Coast family. In 1840 he headed west, painting nature studies as well as intense portraits of Native Americans and white settlers. His most famous work, Long Jakes, features a rugged fur trapper.

Another, Death Struggle, features a Native American and a trapper locked in mortal combat as they tumble together off a cliff. His style was grand and lush and captured the public imagination at a time when the myth of "the west" was being born.

Fame was short-lived. In 1848 he began to suffer from mental illness. He became convinced that God was speaking to him on the streets of New York City and was taken to a mental asylum, where he died 19 years later aged 48. Having examined his records, Clark says that Deas was suffering from schizoaffective disorder. "He had religious delusions and that also ties in with the age of onset of his condition," she said.

Many of his paintings take on the issue of race and the struggle to make a living in tough times. These themes chime with modern-day concerns. "You can look at these paintings and see in them not just musty old messages from the past, but things that are really relevant today," Clark said. Many of the lost works are known from catalogue references.

In chasing up these cold leads, Clark has employed genealogists to trace the descendants of those who bought a Deas. One in particular, painted after Deas had been confined, featured a naked man suspended over water from which a monster was emerging. It proved so shocking when shown in New York that it caused another artist to faint. "I would love to find that one," Clark said.

Clark half-joked that she and the staff at Denver Art Museum had thought about keeping a space clear in the exhibition in case a missing Deas was rediscovered. "I am hopeful that this publicity will flush out a Deas. We would make a space for any Deas that magically turns up next month," she said.