not compelling. Whether or not either hypothesis is eventually substantiated, the emplacement of intercrater plains material likely began during an early stage of intense accretionary bombardment (Guest and O’Donnell, 1977) and lasted until the time of formation of intermediate plains material. This general conclusion seems to be supported in the Borealis region by the relative scarcity of craters between 30 km and 60 km in diameter. This scarcity may indicate resurfacing by crater overlap and blanketing by crater ejecta or resurfacing by lava flows. Craters ≥60 km in diameter on Mercury also are relatively scarce compared to similar craters in the lunar uplands northwest of crater Tsiolkovskiy. The reduced density of large craters and basins on Mercury relative to the Moon could be either a function of different crater-population rates on these bodies or an effect of different crustal histories (Schaber and others, 1977). Intermediate plains material has a roughness and crater density transitional between intercrater plains material and smooth plains material. In the Borealis region, the unit occurs in a rather extensive belt that extends from the Shakespeare quadrangle into Borealis north and northeast of Suisei Planitia. Intermediate plains material was first recognized and mapped in the Tolstoj quadrangle (Schaber and McCauley, 1980), where it primarily occurs on the floors of craters. It was identified there by a lower crater density than that of intercrater plains material and by “a lower incidence of small bright-halo craters than are found on the smooth plains material” (Schaber and McCauley, 1980). Both characteristics are also typical of intermediate plains material in the Borealis region. Basin materials Goethe Basin is a large circular depression that measures approximately in diameter from rim crest to rim crest. Goethe is bounded on its north and east sides by a gently sloping wall and discontinuous, low, hummocky rim material that may consist of ejecta deposits. These materials are similar to those occurring around the Caloris Basin in the Tolstoj quadrangle (Schaber and McCauley, 1980). On its west side, Goethe is bounded by at least three subparallel ridges or tilted blocks, which are separated by narrow troughs partly filled with smooth plains material. Hilly and hummocky remnants resembling basin deposits and ejecta protrude above the gently sloping basin wall. They extend southwest and north of the basin beyond a much subdued, low, barely perceptible rim crest for a distance of one-half to one-third of the basin radius. Goethe