Argentina Cancha de bochas

“Scientifically, they are called concretions. They are rocks that are between 220 and 225 million years old. They were formed in a humid environment, a river or lake, from organic matter, it can be a leaf, a piece of wood, a bone, and a small particle of that organic matter is transformed into the nucleus that, over time, with what it receives from water, sand, salts and carbonates, adheres to that particle. Over time and millions of years, a ball is formed that becomes a solid and compact rock.”

CPL filter sometimes useful.

Unfortunately, you have to wait for the park to open and then for the guide to decide to go on the tour. You arrive at the place no earlier than 10 AM with the sun already very vertical and strong.