The discovery of what might be a runic stone from Scandinavia in the surf near the small town of Berryville, Maine, tips this tale on its mildly humorous careen. Some of the villagers want the stone to be proof that Berryville was once Vinland, discovered by the Vikings long before Columbus sighted San Salvador. Others--particularly the liberal intelligentsia who make up the summer people--are afraid the stone will attract day-trippers to Berryville and sully their idyll. The leader of the anti-rune faction is amusing enough: a civil liberties lawyer from Boston who is paranoid about trespassers, ringing his estate with an electric fence and standing watch with binoculars. As the wrangle over the stone heats up, what is unmeltable in America's desultory melting pot bubbles to the surface as Italian and Swedish descendants jockey to protect their ethnic honor. Trillin also gets some smiles out of the cupidity of small town merchants. By and large his portrait of Berryville is affectionate, but readers addicted or even inured to the wilder comedy that exploded in the 1960s may find this amiable trifle a degree tepid.