An anonymous £600,000 donation to a museum was made in memory of a geologist's great-great-granddaughters, the building's owners have said.
The gift was given to the National Trust for Scotland-owned Hugh Miller Museum and Birthplace Cottage in Cromarty last month.
The trust said it was made in memory of Miller's descendants Marian, Bright and Lydia Middleton.
A fund will be set up using the money to help cover the museum's costs.
The Middletons farmed in the Black Isle for more than 200 years. Bright was the last member of the family to farm in the area.
Mr Miller's study of fossils and rocks around Cromarty in the 19th Century has been credited with contributing to a greater understanding of Earth's history.
Modern geologists have described him as a hero.
The museum was under threat by cost-cutting at the trust.
However, the charity said a full-time curator would now be reinstated and during the summer opening hours restored to seven days a week.