WASHINGTON (AP) _ David Stillman, a 14-year-old Idaho kid with glasses and braces, relied on hours of study and at least one educated guess to win the National Geography Bee Thursday. It was his second try in two years at the top prize.

Seated beneath the seal of the National Geographic Society, the 10 finalists, all boys, showed such knowledge of maps, geology, history and religion that some adults in the audience were unashamed to shrug in ignorance at the questions.

After 40 minutes of the arcane and unpronounceable, it came down to one question: ''What type of land form is commonly associated with orographic precipitation?''

''Mountain'' was David's answer. He won a $25,000 college scholarship.

Carlos De La Fuente, whose wide grin and confident manner in the presence of TV cameras made him an audience favorite, guessed ''rain forest.'' The 11- year-old from Chandler, Ariz., went down to defeat. He got a $15,000 scholarship and said he'd be back next year.

Stillman, now the pride of Nezperce, a town of about 500 in western Idaho, said later he put in about half an hour a day of study but still had to make a ''complete guess'' at one question, which he couldn't remember after the bee.

For some of these questions, though, all the guessing in the world wouldn't have done any good.

Try this one:

''Olduvai Gorge in Africa is part of a fault system where scientists have found a great number of hominid fossils. Name this fault system.''

If you answered ''East Africa Rift System,'' then you might also have read enough books to know what a karst is.

The answer: ''The term for the type of topography characterized by sinkholes, caverns and underground streams.''

Here's another one:

''According to the theory of continental drift, during the Mesozoic era, the supercontinent Pangea became two landmasses. The southern landmass is called Gondwanaland. What name is given to the northern landmass?''

It's Laurasia.

The bee was part show-biz, hosted by Alex Trebek of TV's ''Jeopardy'' fame, who found himself in a battle of wits with artillery one rarely finds on a commercial game show. He had his pronunciation corrected and had to bat back complaints about name cards and flashing lights.

At one point, he found himself having a huge bow and arrow pointed at him to illustrate a question he was reading about the fierce Yanomami people of South America.

The National Geographic Society, which started the bee three years ago, estimated that 5 million students in fourth through eighth grades took part in the initial round at 38,000 schools in January and February.

State bees were held April 5 to select 57 contestants, who included representatives of 50 states, the District of Columbia, U.S. territories and Defense Department schools abroad. They competed in a preliminary round Wednesday from which the 10 finalists emerged.

The other eight finalists were Matthew Coldiron, 14, of Somerset, Ky.; Liam Burnell, 13, of Falmouth, Maine; Danny Dudis, 14, of Pocomoke City, Md.; Stephen Gent, 14, of Gulfport, Miss.; Joe Turner, 14, of Bernie, Mo.; Tom Barringer, 11, of Delta, Ohio; Rob Leitner, 14, of Carlisle, Pa.; and Eliot Brenner, 13, of Richmond, Va.