In 1747 the Roman publisher Venantius Monaldinus produced a Latin edition of two early works proposing the animal origins of fossils (reproduced here from the 1752 printing). The first, originally entitled La vana speculazione, first appeared in Italian in 1670. Its author, Agostino Scilla (1629–1700), was a skilled artist who painted fresco cycles in several churches in his native Sicily. From examining the fossils found in the strata on either side of the Strait of Messina and observing sedimentation in rivers, he deduced that not only molluscs but even the mysterious glossopetrae (actually fossilised sharks' teeth) were the remains of living organisms. The second essay, by Fabio Colonna (1567–1640), a Neapolitan botanist who corresponded with Galileo, appeared in 1616 as part of a longer Latin treatise, and also argues for the organic origins of glossopetrae. The book is illustrated by engravings of both fossil and living marine animals.