If The Goonies starred adults, contained a good pamphlet’s worth of history, drew half the zesty laughs and lacked the comic relief of Sloth and Chunk, it would be National Treasure.

It’s hard to imagine this film becoming a generational classic. But it represents producer Jerry Bruckheimer’s fine distillation of what could have been PG-13 material to a more family-friendly PG.

The action and death by falling is no more violent here than it is in film company Walt Disney’s G-rated material, and there is enough clean comic relief (mainly from actors Justin Bartha and Jon Voight) to keep 10- and 11-year-olds laughing.

Its only drawback, and it’s a big one, is that at almost 135 minutes, it’s entirely too long. The first act is snail-paced, and the piling-on of clues grows wearying.

And kids already might be squirming by the end of the overly expository prologue, which outlines the treasure at the film’s center — the long-lost loot of the Knights Templar.

The press kit acknowledges similarities to Dan Brown’s The Da Vinci Code but claims Treasure was in script development much earlier. Adults who have read Brown’s book might find the similar plot conceit and cryptology less interesting.

Pursuing the Templar treasure has become a scholarly obsession for the Gates family, represented in the latest generation by Ben Gates (Nicolas Cage). An Arctic expedition, funded by his money-man Ian (Sean Bean, who can stop playing Euro-trash villains), uncovers a clue pointing to a treasure map hidden on the Declaration of Independence.

When Ben shoots down Ian’s suggestion to steal the document, Ian tries to shoot down Ben. Ben and his sidekick Riley (Bartha) escape, but realize they must steal the Declaration before Ian does. Their heist touches off an Eastern seaboard treasure hunt that’s as much a lesson in American history as it is an adventure.

Though it’s only a starting-off point as far as the narrative is concerned, the film reaches its peak of entertainment during Ben’s attempt to snare the Declaration.

Director Jon Turteltaub, helming his first action film, hits the right suave suspense beats of the robbery and generates Treasure‘s best action sequence for the getaway — an old-fashioned car chase in which the damsel in distress hangs from the swinging panel door of a van.

It’s also the segment of the film in which Cage shifts, albeit only slightly, out of disinterested paycheck-cashing mode into any sort of character. Bartha has fun in the role Cage might have excelled in 10 years ago, brightening the film with geeky observations and a great moment when he one-ups Ben in historical knowledge.

Per the Bruckheimer formula, they’re flanked by prestigious character actors with sketchily drawn character motivations.

Voight plays Ben’s father, a humorously outspoken hermit who has given up on the treasure search for reasons that are never quite clear. And Harvey Keitel plays an FBI agent on Ben’s trail with all the smooth tones of his Wolf from Pulp Fiction.

But given who Keitel turns out to really be, and the resources likely at his disposal, it seems implausible that he would let, well, anything that occurs in the movie take place.

It’s a nagging that-wouldn’t-happen moment in a film where it wouldn’t matter if we didn’t have the unnecessary extra half-hour to contemplate the plot holes.

Given the persistence of those problems, National Treasure is no motherlode of adventure, but it is a minor find worth digging up on video someday.