A stone plate reached into the sea, in the stone are actually shells from shellfishes compressed into a plate and created this stone-like Beach.
The shells can be dated back to about 40 million years. In the past, this area is fresh water and many shell fishes live here, but there was a shift in tectonic plates causing salt water to come into the area the salt create reaction that fuse shells together called Shelly Limestone and about 40 cm thick. When tectonic plates shifted again it raise the land and these fossils can be found. This is located the sea shore of Tale Baan Lam Pho only 15 km from the city.
Reference: https://www.tourismthailand.org/Attraction/75-million-year-old-shell-cemetery
