BUFFALO - It is known as the map that changed the world, William Smith's 1815 charting of Great Britain's underside.

The London Geological Society keeps its rare copy behind blue velvet curtains, which are swept open three times a week for visitors.

The Buffalo library keeps its copy folded up in a box. At least it did.

This week, the map became the centerpiece of the first of a series of exhibitions meant to showcase the library's 30,000-title Rare Book Collection, its multimillion-dollar pride and joy.

With a money squeeze forcing the 52-branch county library system to close 16 branches, supporters hope to raise funds by raising awareness of the treasures in its vault.

Smith's map of Great Britain is the first geological map of any country in the world and, through its charting of the earth's layers and fossils, is said to have influenced the work of Charles Darwin and the world's coal and oil industries. It even inspired a best-selling book.

Smith handmade 400 copies of the map, of which about 40 still exist, including two in the United States. The other is at the Library of Congress.

Buffalo even had stored with its copy Smith's hand-colored sketches of the fossils he researched for 20 years to make the map. The British Geological Society wants to borrow the sketches for an exhibit being planned in London.

"They don't even have them at the Library of Congress and we had them in our basement," Library Foundation Executive Director Anne Leary said.

The exhibit, put together with the help of University at Buffalo scientists, has geologists from all over the country calling for hotel and exhibit information. "It's almost like their bible or Holy Grail," Leary said.

Simon Winchester, author of the best seller, "The Map That Changed the World," helped open the exhibit, waiving his usual $20,000 speaking fee. Winchester's book traces the life of Smith, who, while digging canals, noticed layers in the rocks and the fossils that varied from layer to layer. His principles laid the foundation for a new chronology of the earth's history and provided a tool for detecting coal and oil reserves.

After publishing his 6-by-9-foot map, Smith ended up in debtors' prison, a victim of plagiarism, and was homeless until the significance of his work was recognized years later and he was dubbed the "Father of English Geology."

"I would argue that William Smith turned a lot of things on their head with this map, which was a hugely important and profound development," Winchester told The Buffalo News.

The map will be on exhibit at Buffalo's Central Library through the end of the year.