In the monastery complex there is geological and paleontological find of sediments with a very rich well-cared fossil’s fauna of mollusks, which has the great importance for the geology of Europe. This find is known as the one of the biggest significance and is the natural monument. It is situated on the east side of the monastery gate in Luka stream (Kalina water).
The richness of fauna contributes for Grgeteg to become well-known in the world, as the place of the lower pliocena – pontifical floor, in the limits of the former Panonian sea. There were found more than forty species, of which twelve were found here for the first time. It was found more than hundred years ago, as the well-known find of the pliocenian fauna of mollusks.
Because of it’s scientific value this locality is protected in 1974.