The purpose of this paper is to give a brief description of the volcano, and to report progress in the detailed mapping and petrologic study of its caldera. The increasing use of the Paulina and East Lake areas for recreation and nature study, and widespread interest in the geology aroused by NASA's use of the Newberry area as a training ground for the astronauts and by the field trip in connection with the State of Oregon Lunar Geological Field Conference, merits a preliminary report before completion and publication of the detailed petrologic studies in which the authors are engaged.