gravel, a soil or unconsolidated rock in which pebbles are the most obvious component, known in French as graves, from which the two appellations below, and the DOC above, take their names. Gravel is the most distinctive soil type of Bordeaux’s so-called left bank wine regions. It is said that glaciers, slowly moving down to the Atlantic coast from the distant Pyrenees, followed the course of the nearby river, pushing back its high right bank. When glaciers melted, the pebbles remained near the surface. The vineyards of the graves are, not surprisingly, characterized by their gravelly surface and gravel is nowhere so prevalent as at Ch haut-brion, where in places it is 16–20 m/50–65 ft deep. Such soils offer excellent drainage, imposing on the vine the slight water stress favoured for wine quality. See vine physiology and soil and wine quality.