SWAMPWALKER'S JOURNAL: A WETLANDS YEAR

In the final volume of his ''wet-sneaker trilogy'' (following The Year of the Turtle and Trout Reflections), naturalist Carroll covers four seasons of wading through marshes, swamps, bogs, and fens. He follows four-toed salamanders, red-spotted newts, frogs, water scorpions, diving beetles, fairy shrimp, and a turtle he names Ariadne, often by unsqueamishly thrusting his hands into tangles of mucky roots and stems. Although he has an occasional tendency to wax purple with his prose (''Mellifluous northern orioles, lilting titmice, and fluting hermit thrushes weave tone poems throughout the summer day''), Carroll's eye for detail serves him well, whether he's spying on a tiny garter snake struggling to suck down a much larger wood frog or watching a raccoon savagely digging a turtle out of its shell. B