I was a guest lecturer on jazz for two music appreciation classes at a private New England liberal arts college yesterday. You might say I had my work cut out for me. None of the 42 students in these classes had ever heard of Wynton Marsalis, Diana Krall, Charlie Parker, Thelonious Monk, or Duke Ellington. That's right, DUKE ELLINGTON. I double-checked, tried to enourage even a wink or raised eyebrow from anyone who might have felt shy about acknowledging their sophistication, but it was to no avail. What added to my shock and dismay over this revelation of American cultural illiteracy was learning that a couple of the kids had played in high school jazz ensembles.