"Did you ever stand and shiver ... just because you were looking at a river?" So sang Bob Dylan's early mentor, Ramblin' Jack Elliott, about a youthful trip to New Orleans where the Mississippi River's inscrutable currents embodied the sense of mystery he felt here — a sensibility echoed by Simon Gunning in this sprawling retrospective. Intrigued by the Big Muddy and its contrast with the pristine shores of his native Australia, Gunning devoted much of his life to exploring its awesome charisma and the city it shaped. In his early painting The Messenger, a bicycle courier navigates a narrow backstreet that ends with a huge freighter looming tall above antique buildings. Schiro's at Sunset (pictured) depicts 1990s Marigny as a panorama of street life, including stoop sitters, produce wagon vendors and stray dogs foraging amid discarded fried chicken bags as an elderly man in a sleeveless undershirt clutches a bag of groceries. The Haunted Wharf is a chaotic river vista framed by the skeletal ruins of a dock, a view that contrasts sharply with his gorgeously serene swamp scenes. Gunning is at his mysterious best in works like Waiting, where ships like massive floating monoliths gather at the mouth the river, the placid surface of which belies roiling currents surging into the Gulf Stream on their global journey. Mississippi Delta native Maude Schuyler Clay returned home to record her world in photographs after a stint as a photo editor in New York. For her, the Delta is its people as they appear in their remote rural settings, as we see in images like Bonnie Claire, Green Car, a view of a young woman looking much like a pre-Raphaelite angel appearing with a 1953 Oldsmobile. In Bill with Gun, her cousin, legendary color photography pioneer William Eggleston, clutches a vintage shotgun in a characteristic pose that takes him out of the world's great museums and returns him squarely to his Mississippi Delta roots.