Jazz has had its share of archival discoveries, not the least of which were Dean Benedetti's recordings of Charlie Parker. But the discovery of more music from the Thelonious Monk Quartet with John Coltrane is made all the more extraordinary because so few knew it existed and the only official recordings by this band were made in its first weeks of existence. Now, a forgotten November 1957 Carnegie Hall concert taped by Voice of America radio has been discovered by the Library of Congress with two appearances by the quartet.