Why was the Ordovician System introduced into the geologic time scale?

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Cambrian paleogeography — Cambrian Period Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the late Cambrian Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

The Ordovician System was introduced to resolve a scientific dispute regarding the boundaries of the Cambrian Period and the Silurian Period.

In the 19th century, geologists Adam Sedgwick and Roderick Murchison independently defined the Cambrian and Silurian systems, respectively, while mapping rock successions in Wales. As both geologists expanded their systems, their definitions began to overlap, leading to a significant scientific feud.

To settle this conflict, English geologist Charles Lapworth proposed the Ordovician System in 1879. Named after the Ordovices, an ancient Celtic tribe from northern Wales, the new system was designed to encompass the disputed interval where the two original systems overlapped. Although the proposal faced initial resistance in Britain, it eventually gained widespread international acceptance and was officially adopted in Britain by 1960.1