CARBONIFEROUS PERIOD (358,9-298,9 Ma)
Reference to the coal contained in the system in England.

Main events: the arachnids, the first reptiles and formation of coal deposits.

Lifeforms: winged insects and amphibians were of gigantic dimensions, the four-lung arachnids diversified, and the first small reptiles appeared.

Paleoenvironment: during the first half of the period, the Earth was covered with forests and marshy vegetation. The climate was warm and very humid, and the atmosphere had oxygen levels that almost doubled the current ones. In the second half of the Carboniferous, Earth's overall climate cooled and the "Carboniferous Rainforests Collapse" occurred, causing the accumulation of coal deposits. All the continents had come together in a single supercontinent: Pangea.

Cobblestones: not technically feasible (commercial concrete).