Aug. 3 (UPI) -- A number of famed Spanish stone monuments feature gastropod fossils dating back to the time of the dinosaurs. Using the fossils as a guide, researchers were able to identify the quarries from which the stone was sourced during the 18th century.
The ancient fountains outside the Prado Museum in Madrid, Spain, are made of dolomite, a type of sedimentary rock popular with stone artisans and architects. Prized for its light color, the stone is also characterized by the plethora of snail shells trapped within.
Analysis of the ancient snail fossils allowed researchers to locate the original source of the prized stone.
The snail species, Trochactaeon lamarckim, featured in the monuments hails from the Late Cretaceous epoch. The fossils are 85 million years old.
Researchers used historical records to identify possible locations of the ancient quarries. The fossils allowed the scientists to confirm the exact origin of the dolomite.
"These quarries, lost over a century ago, are located in Redueña in the province of Madrid," researcher David M. Freire-Lista told SINC. "Here the geological formation of the dolomite -- a sedimentary rock similar to limestone -- known as Castrojimeno presents characteristic features, such as a layer containing fossils that do not appear in other areas."
In addition to the Prado Museum monuments, the stone was also used to build the Fountain of Apollo and the Palacio de las Cortes.
"Its petrographic and petrophysical properties, being of particular note its low solubility and porosity, lend it an excellent quality and durability for use in places where water is present, such as these fountains," Freire-Lista said.
Researchers detailed their analysis in the journal AIMS Geosciences.