For Lily Ganshorn, it started as a hunt for meteorites at the beach near her family's cabin at Lake Diefenbaker.

As the day wore on, the six-year-old convinced her father to start breaking nearby pieces of rock which looked like dried-out mud.

"They're so cool," said Lily Ganshorn. "You smash the rocks and then they're so shiny with little animals."

"We found our first ammonite doing that," said Jon Ganshorn, who said his daughter's cousins soon wanted to join in on the hunt. "As soon as we saw that first one, you could tell it was something."

Dragonfly fossil from Lake Diefenbaker, Sask.

Jon Ganshorn said his niece discovered these fossilized remains of a creature resembling a dragonfly near Lake Diefenbaker.

After a few days, one of her cousins found a fossil containing what appeared to be a dragonfly.

Curious, her father sent photos of the fossils to the University of Saskatchewan Department of Geology, where graduate student Meagan Gilbert confirmed the Ganshorns had unearthed remnants of shellfish that swam in the Western Interior sea roughly 75 million years ago.

Fossils from Saskatchewan's 'subtropical' past

"At that point Saskatchewan basically sat right in the centre of this massive seaway that stretched all the way from the Gulf of Mexico to the Arctic." said Gilbert.

"It would have been really shallow and really warm, it would have been subtropical."

Meagan Gilbert

Meagan Gilbert grew up in Eastend, Sask., where she developed a fascination with geology and paleontology in 1991, after scientists found an intact Tyrannosaurus Rex skeleton not far from her home. Gilbert is now pursuing her doctorate in at the University of Saskatchewan. (Submitted by Meagan Gilbert)

She said the Ganshorns' Creteceous-era fossil find included bivalves and prehistoric oysters. She also spotted ammonites, which "are basically like squid with a shell."

She could not identify the dragonfly from the Ganshorns' photo alone, but noted the shellfish species were often prey for prehistoric sea reptiles.

"They would have been food for things like mososaurs, which were basically like 40-foot crocodiles with flippers instead of feet," said Gilbert. "And for plesiosaurs, these long-necked reptiles that would have swam around with paddles."

Bivalves at Lake Diefenbaker

Jon Galshorn stretches his hand next to fossilized remains of prehistoric oysters.

For the time being, Lily and her cousins are keeping most of their finds at their cabin. This is where Lily's father found himself building a rock garden last year to accommodate her burgeoning rock collection.

"We have fun to have these hunts," said the six-year-old, who lives in Martensville, Sask.

Her advice to other fossil-hunters was simple.

"Go down to the lake, look around the shore, then find a big grey rock and smash it," Ganshorn said.

Gilbert said she's glad to see people taking an interest in paleontology, but noted provincial officials consider rarer examples of fossils Crown heritage property. 

"We plan to go exploring all over the place." - Jon Ganshorn 

"You can't always take these things home," said Gilbert.

She added it's important for geology enthusiasts to tell scientists about their finds, especially "well-preserved" examples like these.

"These things die and float to the bottom of the sea," she said. "And because nothing comes along and stomps on them or mixes them around, or rolls them around, these things actually do preserve rather well."

Jon Ganshorn Lily Ganshorn and fossil

Jon Ganshorn holds a fossil along with his niece, nephews and daughter, who've named themselves founding members of the Dinosaur Hunter Gang. (Submitted by Jon Ganshorn)

Dinosaur Hunter Gang has big plans

Jon Ganshorn said he's grateful a relative recently gave his family a quad, which the children will use to transport their treasures when they return to the shoreline to hunt for more evidence of prehistoric life next summer.

Carrying their finds up the sand hills each day became "quite a workout," Ganshorn said.

"Literally I had a set of cargo pants and they would be completely just packed full," laughed Ganshorn.

"I'm a fairly big guy and I'd be sitting there struggling with my arms full of rocks, my pockets full of rocks."

He said Lily and her cousins have now dubbed themselves the Dinosaur Hunter Gang.

Ganshorn fossil ammonite

"The nicest ones I varnish and give a bit of a shine to protect them." said Jon Ganshorn, who tried to keep pace with his daughter, niece, and nephews as they cracked rocks this summer near his family's cabin at Lake Diefenbaker. (Submitted by Jon Ganshorn)

"I'm excited about it, the kids are absolutely excited about it and we go down and get away from the TV and from devices and everything else and get out and search for these fossilized sea creatures," he said.

"We plan to go exploring all over the place."

Lake Diefenbaker child fossil hunter

The fossils turned up along the shoreline of Lake Diefenbaker, which is part of the Bearpaw formation. During the Cretaceous era, aquatic creatures and reptiles sank to the muddy bottom of what used to be a vast inland sea. (Submitted by Jon Ganshorn)