Madras, India, eighteenth century
From the Lewis cabinet

Petrified wood describes a special type of fossilized remains and is the result of a tree having been completely transformed into stone by a mineralization process. All the organic material is gradually replaced, while retaining the original structure of the wooden tissues. The petrifaction process occurs when wood becomes buried under sediment or volcanic ash and is initially preserved due to a lack of oxygen which inhibits its decomposition. In India, a geological site known for deposits of petrified wood exists close to the city of Madras (modern Chennai) where Lewis was based, and this specimen, also listed in his catalogue, may have come from this source.