Salt Bay Chamberfest’s “Music Unearthed” festival is in full swing, with multiple concerts scheduled through August. Events include two concerts at Lincoln Theater, two free concerts at the Coastal Maine Botanical Gardens, a Music on the River recital on Glidden Street in Newcastle, a “listening adventure” at Keyes Woods Preserve led by Coastal Rivers Conservation Trust’s Sarah Gladu alongside SBC Artistic Director Wilhelmina Smith, and a lectu…