In 1899, T. C. Chamberlin proposed that the CO (sub 2) content of the atmosphere decreased during times of enhanced continental erosion, ultimately resulting in glacial epochs. He ascribed the increase in the rate of chemical weathering (relative to the rate of supply of CO (sub 2) from Earth's interior) to increased orogenic activity and globally higher average elevations, which promoted rapid chemical erosion of silicates. The oceanic record of strontium isotopes, preserved in marine sediment, supports his suggestion that glacial climates during the Phanerozoic are in part linked to increases in the rate of global chemical erosion relative to outgassing from Earth's interior. Further, the close correspondence of the major tectonic episodes of the Late Ordovician and Early Silurian, the Devonian, the Carboniferous and Permian, and the late Cenozoic to times of increased continental erosion and glaciation suggests that Chamberlin's hypothesis of the cause of glacial periods should be revived.