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How did Charles Lapworth help resolve the Cambrian-Silurian boundary dispute?

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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 dispute between Adam Sedgwick and Roderick Murchison arose because their respective systems—the Cambrian and the Silurian—overlapped, with Murchison’s Silurian expanding into the upper portions of Sedgwick’s Cambrian strata. This created significant correlational difficulties, as Sedgwick’s system was based primarily on lithology, while Murchison’s was defined by fossil fauna.12

Charles Lapworth resolved this controversy in 1879 by proposing the Ordovician System. He identified that the disputed sequence of rocks—which had been inconsistently classified as either Upper Cambrian or Lower Silurian—was actually a distinct, separate system.312

Lapworth’s solution was supported by his own stratigraphic research in Scotland and Wales, as well as the work of Joachim Barrande, whose study of Bohemian fossils demonstrated a clear succession of distinct faunal groups. By establishing the Ordovician as an intervening system, Lapworth provided the necessary framework to resolve the individual characters of the Cambrian, Ordovician, and Silurian systems.2