Extensive rainforests rich in plant life and super-sized creatures. The vegetation was not the same as the rainforests of today. In the Carboniferous tree ferns and giant club mosses covered the forest floor, with Lepidodendron trees towering up to 40 metres, Great thicknesses of plant material were rapidly covered by sediment from vast river networks, cutting of the processes of decay. This was a time of massive carbon burial, with higher than today’s oxygen levels and lower carbon dioxide levels.

The palaeo-geography of the late Carboniferous time.  Plate movement has sutured Iberia and other southern European elements to the southern edge of Avalonia (the small plate that includes the British Isles) which had previously merged with the Laurussia plate (Laurentia + Russian plates). The massive Gondwana plate (includes Africa) was also moving north. The result, a great mountain chain is thrust upward – the Variscan Mountains. All this is happening around equatorial latitudes, with no lack of rainfall on the mountains and forests, creating a vast network of rivers draining the rain forests. A parallel with the Amazon of today. The overall direction of basin drainage appears to have been northward.

Small selection of plant and animal life from the Carboniferous. Note the trees have very distinct looking and bark and bear cones like pine trees. There is no evidence for flowers in the fossil record for the Carboniferous. Many of the forest dwelling animals, based on their fossils and in some cases fossil tracks, grew to extraordinary sizes, for example the 75 centimetre wingspans of the dragonflies or the 2 metre long millipedes. The high levels of oxygen in the Carboniferous atmosphere (35% as against 21% now) would support higher rates of metabolism and oxygen diffusion through the skin of animals like arthropods and insects that do not have lungs – they breathe through their skins.

The high levels of oxygen are thought to arise from the extensive photosynthesis  by the abundant plant cover, combined with much reduced uptake of oxygen for the breakdown of plant material, due to its rapid burial in the forest swamps. This was a time when Earth was sucking carbon dioxide out of the atmosphere fast.