Pebble tubers along the way, "dinosaur paws"

"Dinosaur eggs"? Silica nodules and silica cords run through the Helvetic silica limestone. The silica comes from silica sponges, which found good living conditions in the early Cretaceous period, i.e. at the time of the formation of silica limestone, and were able to spread en masse in the shallow shelf sea alongside sea urchins.