The western floor of the Miyamoto crater in Sinus Meridiani on Mars exhibits both geomorphic and spectral evidence for aqueous history. It contains a sinuous and narrow ridge that is interpreted to be an inverted channel and is suggestive of past fluvial activity. Phyllosilicates occur in materials that are proximal to the paleochannel, but are not detected on top the ridge. The simultaneous use of the spectroscopic data, high-resolution images, and a digital elevation model show that Fe/Mg-smectites are exposed by erosion. They are associated with polygonally-fractured bedrock which occurs on the slopes of both sides of the sinuous ridge. The observations provide direct evidence of the presence of water and possibly of multiple aqueous events throughout the area.