is older than the smooth plains material by which its wall, rim crest, and most of its ejecta were partly buried. The Goethe impact basin may be older than some intercrater plains material and large craters nearby. It is also much older than the Caloris Basin. (McCauley and others, 1981). Several additional impact structures within and to the south of the Borealis region display sufficient structural detail to be called basins, even though their diameters are less than the arbitrarily chosen 200 km lower limit adopted by Murray and others (1974) for mercurian basins. The largest and oldest of these is Botticelli, a crater in diameter centered at lat 64°N., long 110°W. Only the northernmost parts of the crater’s rim and interior lie within the mapped area, but the ghost remnant of an inner ring now flooded by smooth plains material is recognized (FDS 148) farther south in the Shakespeare quadrangle. Turgenev, in diameter, is large enough to be a central-peak basin (Wood and Head, 1976), even though the peak ring probably has been concealed under smooth plains material. The rims of both Botticelli and Turgenev are covered with densely packed craters, most of which resemble the secondary craters that typically occur on intercrater plains material. Therefore, Botticelli and Turgenev are at least as old as intercrater plains material and may be equivalent in age to the Goethe impact basin. A similar argument can be advanced for the age of the Monteverdi Basin, 130 km in diameter, centered at lat 64° N., long 77° W. in the Victoria quadrangle. The younger craters Jókai and Verdi, which have prominent central peaks and ghostlike discontinuous inner rings, probably qualify as central-peak basins (Wood and Head, 1976). Both structures are considerably younger than the Caloris Basin. No material similar to either the lineated or the secondary-crater facies of the Van Eyck Formation, the most distinctive and distant unit of the Caloris Group (McCauley and others, 1981), can be unambiguously identified in the Borealis region. A few rounded hills or knobs, too small to be mapped, are present; they are morphologically similar to blocks of the Odin Formation surrounding the Caloris Basin in the Shakespeare quadrangle (Guest and Greeley, 1983), and to features of the Alpes Formation around the Imbrium Basin on the Moon. Two of the most striking of these knobs are possibly long and across; they rise above smooth plains material that