"When I make up my mind to it," she wrote, "I can be as willful as the gentlest of my sex."

Born in New Jersey, Clapp grew up in Massachusetts, where she attended the Amherst Academy with poet Emily Dickinson. In 1849, she sailed with her new husband, Dr. Fayette Clapp, to California. They eventually settled in Rich Bar, a wild mining camp on the banks of the north fork of the Feather River.

The doctor tended the miners' broken bones and knife wounds. His wife, one of only two or three women in a camp of hundreds of men, began a series of 23 letters to her sister in Massachusetts about what she saw. They were remarkable for their mixture of wonder and objectivity.

"What a lovely sight greeted our enchanted eyes as we stopped for a few moments on the summit of the hill leading into Rich Bar," she wrote in her first letter. "... While I stood breathless with admiration, a singular sound and an exclamation of "a rattlesnake' from Fayette startled me into common sense again."

No aspect of life in the mines escaped her, from the hard work to the hard living and habits of her male neighbors. Writing about a drunken three-day Christmas spree, she observed "some barked like dogs, some roared like bulls and others hissed like serpents. Many were too far gone to imitate anything but their own animalized selves."

The Clapps divorced in 1856, and Louisa Clapp taught school in San Francisco for a few years before returning to the East, where she died in 1906 at the age of 86.

Her epistles, known as the "Dame Shirley" letters, were first published in a San Francisco newspaper in 1854, and inspired some of writer Bret Harte's most famous stories. The letters are recognized by historians as among the best and most complete descriptions of Gold Rush life in the mines.