At around 250,000 years ago, there was a land lifting process, causing the erosion on its surface. The great eruptions produced amount of lava, creating lava breccias, deposited on erosion-plate, then the fluviatil process brought coarse and formed conglomerate sediment. The cycle would be repeated three times and formed the layer of volcanic sediment of Notopuro Formation, nowadays occupies the high topography ofSangiran.
The golden era of Sangiran were getting faded when the land was eroded, the rivers were dried, hot and dry climate, floods, and the frequent volcanic ash rain. Such condition were not suitable for early human and animal, most of them then migrated to eastern to reach the fertile a rea. (Suwita Nugraha, Wulandari, Iwan SB)