The Herschel 250 μm image processed for subtracting the foreground cirrus emission (see text), is shown. Dark green rectangles represent identifications of structures of which we investigate the association to M 31. Blue contours represent the total column density for discrete and diffuse M 31 high-velocity H i clouds, presented in Thilker et al. (2004) (H i emission from the disk of Andromeda was removed), where we also look for the presence of dust associated to M 31. Contours are 0.5, 1, 2, 5, 10, and 20  ×  10¹⁸ atom cm^-2. The magenta star identifies Davies’ Cloud.