X-ray contour maps of the CFHTLS D1 (left) and D4 (right) fields. The grey-scale shows the smoothed X-ray flux. Detected extended X-ray cluster candidates are ringed and numbered, whilst point-source X-ray cluster candidates are marked by red crosses and numbered field. Both maps cover an area of 1° × 1°, the entirety of which is covered by the CFHTLS deep optical u^∗griz data. The solid lines denote the extent of our near-infrared JHK_s imaging data.