Abstract In the early 1830s Charles Lyell was convinced that much of western Europe had been submerged during the Pleistocene by cold seas strewn with icebergs; the relicts of whose loads of rock and mud occurred on land as boulder clay and erratic blocks. Swiss scientist Louis Agassiz disagreed, considering in 1837 that these were the products of deposition by a great ice sheet. Archibald Geikie realized by 1863 that Lyell was wrong. Mountain glaciers had carved the topography of Scotland and other parts of the UK, feeding an ice sheet that left glacial erratics behind when it melted away. He hoped, in vain, to change Lyell’s mind. Archibald Geikie’s mantle passed to his brother James, who compiled evidence from around the world to demonstrate the correctness of his brother’s thesis. It was published in 1874 just before Lyell died still arguing for the correctness of his iceberg theory, which gave us the word ‘drift’ for the unconsolidated deposits mantling the UK. Even so, by then Lyell had gone some way – no doubt partly influenced by the Geikies – to accepting that in certain instances glacial action had, indeed, moved large erratic blocks – locally even uphill, as in the Jura.