Nothing like Earth

"So far excavation had struck no deeper than a shallow level of rock formation, whose complicated geological structure confused even the most experienced of the planetologists. Once they had driven shafts down to the basalt base — itself indubitably more than a billion years old — they discovered that the deposits immediately above contained carbon of organic origin which showed highly advanced stages of recrystallization. At first the scientists believed this layer to have been the original ocean bed. But then they came upon true coal beds with fossils of a large variety of plant species that could only have existed on the dry land. Little by little they gained a clearer picture of the life forms that had existed at that time on the continent of Regis III." - The Invincible by Stanisław Lem.