The Late Neogene-Quarternary Sedimentary basins in the middle part of the Fossa Magna are classified as follows: 1. Around the Nagano Basin, the geologic structure between the Neogene and Quarternary sediments are concordant with each other. Each basin had a tendency to migrate gradually from the southwest to the northeast. These facts indicate that the characters of the basin-forming movement in these areas hadn't changed from Neogene to Quarternary. 2. Aqueous pyroclastic sediments which are widely distributed over the Motojuku, Kirizumigawa and Akima districts, were formed in the Late Miocene sedimentary basins. In these areas the basin-forming-movements were characterized by the depression along the faults and the succeeding volcanisms. In the Pliocene-Pleistocene, no sedimentary basin have been formed in these areas. 3. The Komoro Group, and the Enrei and the Sanjiro Formations, which are the Middle Pliocene-Middle Pleistocene pyroclastic sediments, are distributed extensively around the Yatsugatake volcano and adjacent areas. Their lithologic features are mainly aqueous in their lower part but terrestrial in the upper part. It seems that a shape and size of a basin, and volcanisms in this area were controlled by some tectonic lines formed in the Early-Middle Pliocene. 4 The large amount of gravels are accumulated in the Matsumoto Basin. Most of them had been derived from the Northern Alps and eastern Uchimura mountain areas in the Middle-Late Pleistocene. In this area the Itoigawa-Shizuoka Tectonic Line and subparallel faults run from north to south. It may be that these faults had play an important part in a basin forming process. There is no volcanism in this basin, but the basin-forming movement may be assumed to connect with the volcanism on the Japanese Alps complex.