Morainic sentence example
Till drumlins, notably abundant on the lowland about Boston and the highland near Spencer; morainic hills, extending, e.g.
The glacial drift east of the Missouri river, unlike that of the New England states, is remarkably free from boulders and gravel, except in a few morainic belts.
The morainic belts and other obstructions in the drift plains hem in the waters in the intervening basins and create what are called " glacial lakes," var y ing in diameter from a few yards to several miles.
The till plains, although sweeping in broad swells of slowly changing altitude, are often level to the eye, and the view across them stretches to the horizon, unless interrupted by groves of trees along the watercourses, or by belts of low morainic hills.
The great ice sheets formed terminal moraines around their border at various halting stages; but the morainic belts are of small relief in comparison to the great area of the ice; they rise gently from the till plains to a height of 50, 100 or more feet; they may be one, two or three miles wide; and their hilly surface, dotted over with boulders, contains many small lakes in basins or hollows, instead of streams in valleys.Advertisement
The morainic belts are arranged in groups of concentric loops, convex southward, because the ice sheets advanced in lobes along the lowlands of the Great Lakes; neighboring morainic loops join each other in re-entrants (north-pointing cusps), where two adjacent glacial lobes came together and formed their moraines in largest volume.
The discovery of this significant looped arrangement of the morainic belts is the greatest advance in interpretation of glacial phenomena since the first suggestion of a glacial period; it is also the strongest proof that the ice here concerned was a continuous sheet of creeping land ice, and not a discontinuous series of floating icebergs, as had been supposed.
Thus local sheets or aprons of gravel and sand are spread more or less abundantly along the outer side of the morainic belts; and long trains of gravel and sands clog the valleys that lead southward from the glaciated to the non-glaciated area.
Its sources are in the morainic lakes in northern Minnesota; Lake Itasca being only one of many glacial lakes which supply the headwater branches of the great river.
Within the Archean protaxis they are of the most varied shapes, since they represent merely portions of the irregular surface inundated by some morainic dam at the lowest point.Advertisement
A notable feature of Finland are the asar or narrow ridges of morainic deposits, more or less reassorted on their surfaces.
North of the morainic belt the effect of the glaciation is seen in the irregular courses of the streams, the numerous lakes and freshwater marshes and the falls and rapids along those streams displaced by the glaciers from their former courses.
The coast of the Baltic is rocky only in the island-studded region at the head of the Baltic basin proper - a submerged lake-districtand the littoral generally is a typical morainic land, the work of the last great Baltic glacier.
The Quaternary epoch is represented by vast morainic deposits in the valleys of the Tian-shan.
This depression is occupied in great part by a series of lakes, some of these filling transversal breaches in the range, whilst others are remains of glacial reservoirs, bordered by morainic dams, extending as far as the eastern tableland and corresponding in these cases with transversal depressions which reach the Atlantic Ocean.Advertisement
To the glacial action is also due the extensive removal of the original soil from the uplands, and the accumulation of morainic hills in many localities.