Gradual subsidence of the Correlative elevation of the Cordilleran region and decay of the western part, at least, of the great glacier, with deposition of great plains, which was probably the boulder-clay of the interior more or less irregular and led to plateau and the Yukon basin, of the the production of extensive lakes lower boulder-clay of the littoral in which interglacial deposits, and probably also, at a later stage including peat, were formed. (and with greater submergence), of the interglacial silts of the same region. Re-elevation of the Cordilleran Correlative subsidence of the region to a level probably as high plains, which (at least in the as or somewhat higher than the western part of the region) present. Maximum of second period exceeded the first subsidence and of glaciation. extended submergence to the base of the Rocky Mountains near the forty-ninth parallel. Formation of second boulder-clay, and (at a later stage) dispersion of large erratics. Partial subsidence of the Correlative elevation of the Cordilleran region, to a level plains, or at least of their about 2,500 feet lower than the western portion, resulting in a present. Long stage of stability. condition of equilibrium as Glaciers of the second period between the plains and the considerably reduced. Upper Cordillera, their _relative_ boulder-clay of the coast probably levels becoming nearly as at formed at this time, though perhaps present. Probable formation of the in part during the second maximum Missouri coteau along a shore-line of glaciation. during this period of rest. Renewed elevation of the Simultaneous elevation of the great Cordilleran region, with one plains to about their present well-marked pause, during which the level, with final exclusion of littoral stood about 200 feet lower waters in connection with the sea. than at present. Glaciers much Lake Agassiz formed and eventually reduced, and diminishing in drained towards the close of this consequence of general amelioration period. This simultaneous movement of climate towards the close of the in elevation of both great areas Glacial period. may probably have been connected with a more general northern elevation of land at the close of the Glacial period.