River Terraces

River-Terraces, terrace-like remains of its own gravels and other alluvium cut into and abandoned by a river as it narrows and deepens its channel, each marking the level of a former flood-plain. In Europe there are commonly three such terraces, known, as the high-level gravels, the middle terrace, and the low-level gravels, the highest being the oldest. In Maine and elsewhere there are four, five, or even six or seven levels, as in the valley of the Connecticut, and the period to which they owe their formation, that immediately following the Glacial Period, has been termed the Terrace Period. Though there can be little doubt that the successive terraces indicate a shrinking of the volume of water in the rivers from the time when they were swollen with the melting snows of later Glacial times, they probably also indicate successive uplifts of the land, increasing the velocity, and consequently the scour, of the rivers, whilst raising their former flood-plains beyond reach of inundation.