(a) Location of the lithological outcrops and marble samples (n^o 1 to n^o 25) on the satellite map of the central quarry C23. The beige colour shows the areas covered by ruins or excavation debris, making the outcrops inaccessible; (b) 5000th scale geological map of the quarry C23. Delian constructions induce rapid variations in topography (as in the theatre), resulting in anomalous contacts on the map. The red lines locate the two cross sections C and D described below; (c) Cross sections C (left) and D (right) located in quarry C23.