Of all the places to discover a lost city, this pleasing little community seems an unlikely candidate. There are no vine-covered temples or impenetrable jungles here — just an old-fashioned downtown, a drug store that serves up root beer floats and rambling houses along shady brick lanes. Yet there’s always been something — something just below the surface. Locals have long scoured fields and river banks for arrowheads and bits of pottery, amassing huge collections. Then there were those murky tales of a sprawling city on the Great Plains and a chief who drank from a goblet of gold.