Canada's trade negotiators are falling down on the job. While fussing over minor items like wheat and wood pulp, they allow their country's greatest product to remain unavailable in the U.S. We're talking about albums by Quartette. These four women (Cindy Church, Caitlin Hanford, Colleen Peterson and Sylvia Tyson) have all made fine music on their own. But like early Crosby, Stills, Nash & Young, their talents when combined exceed the sum of the parts. This, their second album, continues to cover a wide range of styles. It contains less "pure country" than their debut, but still covers bluegrass, cajun, folkish leanings and even blues. Whatever they do just comes out wonderfully. Almost every song is a highlight. The only real complaint is that the packaging neglects to mention the lead singer on each track, leaving newcomers confused about who's who. Everyone involved deserves to share the credit equally when an album is this good.