Images obtained using the SuperCam Remote Micro-Imager (RMI) and the Mastcam-Z camera of the Perseverance rover provide in-situ observations of Jezero crater western fan in various locations along the traverse. At the current front of the fan, the most striking features observed are steeply dipping strata, with dips from 15 to 35°. They are composed of packages of planar beds of sandstones and conglomerates, 15 to 25 m in thickness, and 50 to 100 m in lateral extension. In two cases, we were able to observe from the ground conical forms with variations of dip azimuth from one side to the opposite side. These steeply dipping beds are capped by subhorizontal beds, composed of sandstones that are locally conglomeratic and cross-bedded. This architecture is interpreted as foresets (dipping beds) and topsets (fluvial beds) of a deltaic sequence, similarly as it has been observed at Kodiak from the landing site. In deltaic deposits, the topset-foresets transition marks the lake level at the time of deposition. We observe several of these transitions at various places and elevations, from the topmost location north of the Belva crater (-2410 m) to the lowermost elevations at Kodiak (-2500 m). In cross-section, these locations are located further away from the fan apex such as that they are interpreted as an advance of the delta on the crater floor by progradation during falls of the lake level (forced regressions). At the top of the whole sequence, boulder-rich conglomerates truncate the deltaic sequence, and may have formed by late-stage floods of uncertain origin (glacial melting, lake dam break, etc.), potentially disconnected from the lake activity. In summary, the visible part of the western fan records deposits predominantly related to the last stages of lake activity, rather than formed during the initial lake filling. Deposits from the latter may be buried, although some of them may be found in the Shenandoah formation that underlies the deltaic sequence.