Mark Renz knows he's on a successful fossil expedition when he realizes that the families he's guiding are so focused on looking for treasures, they're not hearing him talk. "That's when you know they're really into it," says Renz, owner of Fossil Expeditions, a Lehigh Acres, Fla.-based business that guides families on water expeditions to look for fossilized shark teeth, turtle shells and stingray plates that are 15,000 years to 15 million years old.

Renz, who guides people on the water ranging in age from4 to 94 years old, uses kayaks as an accessible and fun way for families to navigate through the Southwest Florida waters while looking for ancient treasures. He says that kids are some of his favorite participants because of their creative and logical questions.

Around the country, families are enjoying boats to pursue all types of treasures: gold in Northern California or Alaska; agates on Oregon beaches; ancient coral on Michigan's shores; fossilized teeth in Florida's streams; migrating shorebirds on the Atlantic Flyway; or animal-shaped rocks in Maine. Such outings are easy adventures that only require a little research and creativity on the captain's part.

The expeditions are an excellent way to engage families in treasure-hunting activities, especially when the journey can be half the fun. That's where the boat comes in. Don't think kayaks or canoes are the only way to reach difficult-to-access locations. Many types of boats can become treasure-hunting vessels.

In many cases, shallow-draft powerboats are best for scouring shorelines. Bring double anchors so you can keep the boat secure when you wander away. Pontoon boats, deck boats or aluminum craft are ideal. Sometimes, personal watercraft also do the trick - they maneuver easily and can handle shallow water. If snorkeling is involved, consider a boat with a large swim platform to make it easier for the family to get on and off with gear.

Once underway, treasure hunting can be a unique tool for teaching kids. "I try to impress upon kids that this is a scientific treasure hunt, and what's significant to science we'll hand over to researchers, but if we find something that's not, then you can take it home and put it on your shelf," Renz says.

Renz says a British family he recently took out had a 4- and 6-year-old, both of whom were fascinated by the potential for finding fossilized horse teeth that are commonly found on Florida's corkscrew-turning streams and rivers miles inland from Charlotte Harbor and the Gulf Coast. "They asked in their cute accents, 'Mark, why are horse teeth down there with shark teeth?'" says Renz. "And I explained to them that long ago, land and ocean traded places over time."

Boater Peggy Grover likes to recall the summer camp she hosted for some of her seven grandchildren in Michigan, where she and the kids would find Petoskey stones dating back to about 350 million years ago - along with polished beach glass.

Grover would fill a toy treasure chest with the stones and glass, and then bury it along the shore. She'd stick a tiny flag atop for the youngest of her grandchildren.
Then she'd write a series of clues and head out with the kids on a watery hunt that ended in the spot where the chest was buried.

When California boater Beth Nelson goes on trips with her two kids and husband, they keep an eye out for nature's offerings and relish in the unexpected surprises. On a boating trip in their 16-foot skiff to the Sierra Nevada's Twin Lakes, near Bridgeport, Calif., the family pitched a tent in the campground and launched their boat to fish and explore the region.

The foursome hiked to a geothermal hot springs near the lakes, where they found nearby pools that were so warm and soothing that her kids, Kelly and Jack Strickland, then 6 and 3, didn't want to get out of the water. But when the spring's temperature started to get too high, they scurried to another pool closer to a snow-melted creek.

Boater Les Anderson of Sterling, AK, raised his two daughters on Alaska's Kenai Peninsula, where the family would make a game of spotting wildlife - beavers were a favorite for his wife and two girls. But one day, instead of the coat of a beaver's back, he sighted a glittery rock: His family and friends found a gold nugget that was worth $100. But even if your score isn't worth a Benjamin, you'll still reap valuable time with your family as you search for that next ancient horse tooth or fossilized rock.

Treasure-Hunting Tips

A. Target your treasure. Every region of the United States has something that will excite kids and adults alike. Not sure what's in your region? Call the county's visitor and convention bureau, local museum or nature center.
B. Remember that "treasure" is subjective. Children will happily seek something without monetary value.
C. Visit your local library before your trip. Children will be more likely to engage if they've seen a picture book, children's encyclopedia or visited relevant websites.
D. Pack for the trip. Snacks, appropriate clothing, hats, sunscreen and drinks are vital for keeping kids comfortable during the "hunt." Also, bring tools to make finding treasures easier - a shovel or rake, for example.
E. Know the rules. Some states have laws regarding collecting fossils, artifacts or other items. Be sure to leave a fossilized area undisturbed.
F. Bring a chart. Hunting for treasures can distract you from basic navigation know-how.
G. Keep an eye to the sky. Changing weather conditions can ruin an otherwise fun trip. Know when it's time to head back to the dock by checking the forecast beforehand and watching the sky for changes.

Photos courtesy of Mark Renz/ www.fossilexpeditions.com.

TREASURE SCORE Kids find Megalodon shark teeth in the Peace River near Wauchula, Fl. (bottom photo).