streams flowing from the glaciated into the nonglaciated region. The terraces of the Connecticut valley have long been celebrated, and Professor Dana has demonstrated that they were produced by the swollen streams at the close of the glacial period.1 Professors N. H. Winchell and Newberry have connected with the same period the gravel deposits marking former southwestern outlets of Lakes Erie and Michigan, when a great volume of water poured from Lake Erie over the watershed between the Maumee and the Wabash rivers, and between that of the small stream entering Lake Michigan at Chicago and the Illinois River. General G. K. Warren has shown that the outlet for all the waters now flowing through the Red River of the North into Hudson's Bay, at one time passed south through Lake Traverse and Big Stone Lake into the Minnesota River, making of it an immense stream, compared with which the present Mississippi at its junction is but a driblet. Lower down the Mississippi valley, where the current of these swollen glacial streams converged, a mighty flood was produced, leaving extensive deposits of gravel high above the present river. These constitute the bluffs of the lower Mississippi, so faithfully studied by Professor Hilgard, and are denominated in the text-books "Orange sands."

When one contemplates the indications of these

1 American Journal of Science for 1875, Nos. 57, 58, 59, and 60.

floods marking the close of the glacial period, he can scarcely help wondering if the deluge of Noah was not in some way connected with them.

XIII. Kames.

In the eastern part of New England the glacial floods left their marks not only in high terraces, but in a remarkable series of gravel ridges, which run across the country in singular independence of the present watercourses. From their resemblance to similar ridges in Scotland these are called "kames"; in Ireland they are named "eskers." Their fullest display, however, in the Old World is in Southern Sweden, where they are termed "åsars"; but now that New England has been more fully explored, the kames of Maine, New Hampshire, and Massachusetts are found to exceed in extent anything of their character before discovered. Between New Brunswick and the Connecticut River as many as thirty well-marked series of kames have been followed from the coast far into the interior; in several instances reaching back more than one hundred miles. One, ending in an extensive gravel plain at Cherryfield, Me., nearly north of Mount Desert, can be traced northward to the foot of Mount Katahdin, a hundred and twenty miles distant, crossing the valley of the Penobscot River twice in its course! Another has been followed from Portland northward through the

Rangeley Lakes, crossing the valley of the Androscoggin at right angles. The series most written about passes through Andover, Mass., crossing the Merrimack at right angles near Lawrence, and disappearing at the sea-level, near Boston.

In the Transactions of the Association of American Geologists and Naturalists for 1841 and 1842, President Hitchcock, of Amherst College, gave a detailed account of this series, so far as then observed.1 He there characterizes it as decidedly the most interesting and instructive case of the kind which he had met with. A map of a mile and a half of it (prepared from surveys by Professor Alonzo Gray, of Phillips Academy, Andover), then supposed to be its limit, was given by President Hitchcock in the same paper. This map, on a reduced scale, reappears in Hitchcock's Elementary Geology."

We cannot improve upon the description of the main features of this formation given by Dr. Hitchcock in his first account of it in 1842.

"Our moraines [kames] form ridges and hills of almost every possible shape. It is not common to find straight ridges for a considerable distance. But the most common and most remarkable aspect assumed by these elevations is that of a collection of tortuous ridges, and rounded, and even conical hills with corresponding depressions between them.

1

1 p. 198.

2 p. 260 (30th edition).

These depressions are not valleys, which might have been produced by running water, but mere holes, not unfrequently occupied by a pond." 1

These bowl-shaped depressions marking the course of the kames (one of which will hereafter be described in detail, for the sake of a chronological calculation 2) are identical in character with the kettle-holes of the terminal moraine. The town of Plymouth, Mass., is a wild waste of kames, its three hundred and sixty lakes being nothing else than so many kettle-holes filled with water.3

The kames of New England are composed of clay, sand, gravel, and pebbles of all sizes, up to those which are four or five feet in diameter. In most places the stones exhibit some signs of irregular stratification; but frequently for a depth of twenty feet or more, signs of stratification are entirely absent. The stones in this formation are never scratched as in the till; but they are more or less subangular, showing abrasion of some kind; and are largely from the north.

1 Transactions of the Association of American Geologists and Naturalists, p. 191.

2 See below, p. 342.

8 A "kettle-hole" should be distinguished from a "pot-hole"; the latter being worn in solid rock by a shallow rapid stream bearing pebbles; whereas the kettle-hole is a depression in a gravel deposit, — a rim of gravel being built up around an empty space.

Plate II. shows a portion of a kame-system. East Ridge, Indian Ridge, and West Ridge are composed of gravel such as was described in the preceding paragraph. They each terminate on the upper surface in a sharp angle, and are respectively, at the points a, b, c, forty-one feet, forty-nine feet, and ninety-one feet above the general level of the country which is itself fifty feet above the river. The reticulations are also shown, with the kettlehole near Pomp's Pond afterwards to be more particularly described. Another kettle-hole is marked at x, which is in the summit of a gravel hill about one hundred feet high. The kame here crosses the river at an acute angle. The portion of the formation shown in the plate may be taken as a fair representative of kames in general. The series indicated are made up of such links repeated.

The manner in which kames were formed has long been a source of contention among geologists. The most probable theory proposed is that kames are contemporaneous with the terraces spoken of in the preceding section, and that, like them, they mark the courses of the floods which closed the glacial period. This explanation gives to the kames something of the character of medial moraines. They doubtless mark, in the more level regions of country, the courses of the surface flow of water during the last stages of the glacial period. It was partly the levelness of the country and the