www.stoneage-antiques.com Tired of looking all over the county for that 20,000-year-old mammoth tusk you simply must have? Follow the cramped pathways inside this ancient little warehouse on the bank of the Miami River and you'll find at least one in stock (for just $4500). Owners Gary and Ryan Stone (father and son) dedicate themselves to keeping the place -- floor, walls, and ceiling -- well beyond cluttered. The preponderance of human artifacts here are actually younger than the Stone Age but definitely of the Pre-Plastic Epoch. The plethora includes wood boxes, wood canes, kerosene lanterns, aluminum Coca-Cola and Pepsi-Cola coolers, brass bells, old hats, older portholes, a bowsprit maiden or two, a boar head here, an antelope head there. African masks, African drums, African stools. You might resist a $395 three-foot-tall red lobster statue and a small $550 "handmade" replica of Pilar, a boat Ernest Hemingway owned in Cuba in 1938. But maybe not a blue or red glass bowling-ball-size float wrapped in rope netting for $20 to $30, or an old wicker fish creel for $35. Some things are too precious for even junk sellers to part with. On the premises is a Shure model 555 Unidyne Dynamic broadcast microphone from the Forties for rental only, because the Stones can make more money repeatedly renting that piece of junk to prop masters than selling it.