Talking of the geological age of the so-called Musashino terrace, some research workers have correlated it with the Shimosueyoshi stage of the pre-Wiirmian age, and others, with the Musashino stage of the Wiirmian age. The difference of these opinions comes from that of views of the horizon of the Kanto Loam covering the Musashino terrace gravels. We have observed that the horizon of these covered Loam varies in different localities; namely -The lower Shimosueyoshi Loam with so-called SIP Pumice lies on the Musashino terrace gravels at the uplands of Tokorozawa, and Omiya, while the upper Shimosueyoshi Loam, with so-called Pm-1 Pumice, at the uplands of Narimasu, Toshima, Hongo, and Akabane. Moreover we think it importnat that the terraces with the Musashino Loam and the upper one are found only along the river Shirako in the north east Musashino upland. Accordingly, we would like to propose the following geomorphologic division. 1) The geomorpologic surface of the so-called Musashino terraces is identified with Shimosueyoshi terrace surface. 2) The terraces, the lowest covered loam of which is the Musashino Loam, should be termed as the Shirakogawa (river) terraces. And these terrace surface is M-surface in the previous division.