The Perseverance rover landed in Jezero crater on Mars, which once contained a lake of liquid water. We report the rock properties encountered by Perseverance during a ten-kilometer traverse extending over 400 meters in elevation, from beneath Jezero's western sedimentary fan to the upper crater rim. These rocks consist of coarse-grained olivine, magnesium- and iron-carbonates, silica, and phyllosilicates, including some of the oldest materials exposed within Jezero. We infer these rocks formed by olivine accumulation in an igneous system of layered intrusions, followed by exposure to water and carbon dioxide that caused extensive carbonation of the silicate minerals. Aqueous alteroverlingation is more pronounced at lower elevations. Higher elevation exposures on the crater rim appear similar to olivine-rich rocks distributed over the wider Nili Fossae region.