First geological survey untainted

The 17th-century Italian academics involved in the first scientific geological field survey were not guilty of allowing politics to dictate their conclusions.

Andrew Scott, a palaeobotanist at Royal Holloway, University of London, believes that the academics' insistence that remains of petrified trees uncovered in Umbria were in fact rocks in the process of being transformed into wood was the logical interpretation given the devilish complexity of the fossils.

Others have suggested that Francesco Stelluti's conclusion in his treatise of 1637 was based on his desire not to challenge the Bible's interpretation of creation in the aftermath of Galileo's heresy trial.

"While Stelluti's conclusions were incorrect, as we believe today, they were logical given the state of geological knowledge at the time. They were also convenient, failing to challenge the status quo, and particularly the church."

Scott has spent six years studying 199 intricate drawings of fossil wood in the Royal Library at Windsor as well as investigating the field sites from which the specimens were unearthed.

The accurate watercolours and pen-and-ink drawings of the remains and their original sites - this is the first known study to record such information - were produced by a professional draughtsman for Prince Federico Cesi, founder of the Accademia dei Lincei. After Cesi's death, a handful were included in Stelluti's short work, which stated it was "not generated from the seed or root of any plant, but only from a type of earth, containing much clay, which is slowly transformed into wood".

Scott returned to many of the sites to undertake fieldwork, including Dunarobba, Umbria, an important 2 million-year-old fossil forest now the subject of a major geological investigation.

He found an unexpectedly large range of preservation, from unaltered to petrified wood. Some specimens were wood-like at one end and stone-like at the other.

"Even with the knowledge we have of fossilisation processes today, it is difficult to explain the different states of preservation occurring in the same horizon at Dunarobba," Scott said.