The geologic time scale or geological time scale describes how geologic time is divided into standardised intervals. It uses the rock record together with the principles of chronostratigraphy to place
Sketch of the Succession of Strata and their Relative Altitudes (William Smith)
One example of an obsolete geological time scale (France, mid-1940s).
The Carboniferous is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period 358.86 Ma to the beginning of the Permian Period, 298.9 Ma. It i
Cliff section through the Serpukhovian Red Wharf Limestone Formation, Wales. A marine limestone at the base of the cliff is overlain by an orange-coloured fluvial sandstone. Subaerial exposure of the limestone during a period of falling sea level resulted in the formation of a karstic surface, which has then been infilled by the river sands. A thin, estuarine silty mudstone overlays the sandstone, which in turn is overlain by a second marine limestone.
Hyden Formation over Pikeville Formation in the Pennsylvanian of Kentucky, US. The exposure has Pennsylvanian-aged cyclothemic sedimentary rocks of the Breathitt Group. The upper part of the roadcut is Hyden Formation, consisting of mixed siliciclastics and coal. The lower part is Pikeville Formation, also having mixed siliciclastics and coal.
Etching depicting some of the most significant plants of the Carboniferous
Ancient in situ lycopsid, probably Sigillaria, with attached stigmarian roots, Joggins Formation, Canada