Giovanni Arduino was born in Italian poverty in 1714. He sought an education at Verona but found that reading books about the Earth didn't do him much good. Instead, he studied the Earth itself, making himself into an expert at mining and surveying. More than an expert in his own time, he made lasting contributions to geology.
In the late 1750s, Arduino drafted a manuscript, a picture from which appears here. He never published it, but the tattered state of the manuscript — now kept at the Biblioteca Civica di Verona — suggests that he showed it to plenty of people. This illustration shows a series of rock formations that Arduino categorized as "primary" and "secondary," with an exaggerated vertical scale for clarity. Arduino's work expanded on the ideas of a Florentine naturalist, Giovanni Targioni Tozzzetti, who published a series of books proposing a two-category classification for Tuscan mountains. In 1774, Arduino finally published his own ideas. The classification system Arduino developed included these categories:
Not surprisingly, many people who heard of Arduino's system forced it into a biblical chronology. Primary rocks, they concluded, must have been deposited right before Noah's Flood, and secondary rocks were obviously applied in the scant 40 days of the Deluge itself. But this was not Arduino's interpretation, even though he had been inspired by the work of Niels Stensen, who did relate his own work to the Bible.
In roughly two and a half centuries since Arduino proposed his classification system, it has seen only some modifications. Primary rock formations were later classified as Precambrian and Paleozoic. Secondary rock formations were later renamed Mesozoic. The names Tertiary and Quaternary survive in geology textbooks and papers to this day.
Narrative text and graphic design © by Michon Scott - Updated January 1, 2022