Spitzer carves zigzagging, whorling lines to suggest the energy lying at the intersection of industry and nature in “Petaluma from the River.” The river - which becomes a tidal slough for most of its length before emptying into the San Pablo Bay - rushes along a crooked path across the paper, passing buildings that cluster together in the center of the Petaluma valley. Spitzer’s signature, nearly vibrating sky suggests the plumes of the famous coastal fog that rolls into the valley and down into the San Francisco Bay.