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In the nineteenth century, Charles de Gerville mentioned Roman millstone quarries on the tip of the Cotentin peninsula. Léon de La Sicotière also discovered possible millstone cutting workshops in Alençon. Today, thanks to a renewed national dynamic, studies of millstones are multiplying and shedding light on a little-known aspect of the ancient economy. The presence of tertiary flint pebble puddingstone is predominant along the Channel, at least from Cotentin to the Pas-de-Calais; it is also found in the south of England, which demonstrates the existence of certain cross-Channel contacts during the Iron Age and throughout antiquity. Alongside these very characteristic Norman productions, some sedimentary and plutonic rocks show petrographic variations that reveal a complex millstone supply in western Normandy. Recent studies have highlighted elements whose geological origin is to be sought at the edge of the Armorican Massif, in the Cotentin peninsula, and in the granitic massifs of Vire and Athis.