It is in New England, also, that kames are to be found in better development than anywhere else in America. These interesting remnants of the Glacial age are clearly described by Mr. James Geikie. His account will serve as well for New England as for Scotland.
The sands and gravels have a tendency to shape themselves into mounds and winding ridges, which give a hummocky and rapidly undulating outline to the ground. Indeed, so characteristic is this appearance, that by it alone we are often able to mark out the boundaries of the deposits with as much precision as we could were all the vegetation and soil stripped away and the various subsoils laid bare. Occasionally, ridges may be tracked continuously for several miles, running like great artificial ramparts across the country. These vary in breadth and height, some of the more conspicuous ones being upward of four or five hundred feet broad at the base, and sloping upward at an angle of twenty-five or even thirty-five degrees, to a height of sixty feet and more above the general surface of the ground. It is most common, however, to find mounds and ridges confusedly intermingled, crossing and recrossing each other at all angles, so as to enclose deep hollows and pits between. Seen from some dominant point, such an assemblage of kames, as they are called, looks like a tumbled sea—the ground now swelling into long undulations, now rising suddenly into beautiful peaks and cones, and anon curving up in sharp ridges that often wheel suddenly round so as to enclose a lakelet of bright clear water.[AZ]
[AZ] The Great Ice Age, pp. 210, 211.
Fig. 29.—Section of kame near Dover, New Hampshire. Length, three hundred feet; height, forty feet; base, about forty feet above the Cocheco River, or seventy-five feet above the sea. a, a, gray clay; b, fine sand; c, c, coarse gravel containing pebbles from six inches to one foot and a half in diameter; d, d, fine gravel (Upham).
Fig. 30.—Kames in Andover Mass.
In New England attention was first directed to kames in 1842, by President Edward Hitchcock, in a paper before the American Association of Geologists and Naturalists, describing the gravel ridges in Andover, Mass. In the accompanying plate is shown a portion of this kame system, which has a double interest to me from the fact that it was while living upon the banks of the Shawshin River, near where the kames and the river intersect, that I began, in 1874, my special study of glacial deposits. The Andover ridges are composed of imperfectly stratified water-worn material, and are very sharply defined, from the town of Chelsea, back from the coast into New Hampshire, for a distance of twenty-five miles. The base of the ridges does not maintain a uniform level, but the system descends into shallow valleys, and rises over elevations of one hundred to two hundred feet, without interruption. This indifference to slight changes of level is specially noticeable where the system crosses the Merrimac River, just above the city of Lawrence. It is also represented in the accompanying plate, where the base of the ridges in the immediate valley of the Shawshin is fifty feet lower than the base of those a short distance to the north, at the points marked a, b, and c. The ridges here terminate at the surface in a sharp angle, and are above their base forty-one feet at a, forty-nine feet at b, and ninety-one feet at c. Between c and b there is an extensive peat-swamp, filling the depression up to the level of an outlet through which the surplus water has found a passage.