The NSW National Parks and Wildlife Service discovery ranger said participants of his tours told him, "I will never look at a rock platform the same again".

During the school holidays, Mr Smart will be leading three tag-a-long tours of the fossils, crystals and rocks along the South Coast at Gerroa, Berrara and South Durras.

Telling an ancient story of volcanos, icebergs and floods, the geologist will lead families and rock lovers alike through the history of what life was like millions of years ago.

"The main place is Black Head in Gerroa," he said.

"It's a magnificent area to go for fossils, and the rocks also tell a lot more.

"We can reconstruct the paleoclimate, we know how the animals lived, the type of feeding patterns they had, where they lived, probably about 20 metres or more below the surface on a shelf off Gondwana, which Australia was a part of back then."

At the Berrara Cove trip, Mr Smart will be joined by another guide to point out the modern-day features of the platform.

"Both plants and types of little critters that live in the pools, like starfish," he said.

"When we've finished there we'll hop back in the vehicles ... we'll follow a track into the entrance at Sussex Inlet.

"By going to those places, it gives the participants a good look back in time to approximately 270 million years ago."

Mr Smart, who has worked in Arnhem Land, said he aimed to give participants skills to recognise fossils and geological features so they could take their own trips to rock platforms.

"I try and make it interesting for the little guys and some of them find the best fossils," he said.