FIG. 1. VIEW EASTWARD FROM MT. MARCY-showing a dome-shaped summit at the right, and sharper wedges on the left in the middle distance. THE POPULAR SCIENCE MONTHLY MARCH, 1906 THE PHYSIOGRAPHY OF THE ADIRONDACKS BY PROFESSOR JAMES FURMAN KEMP, COLUMBIA UNIVERSITY Introduction. The state of New York is shaped like a shoe, with its toe pointing due west and a long spur extending from the heel to the east. In the upper part of the shoe where the ankle of the wearer would be placed, is the Adirondack region, containing 10,000 square miles of very sparsely inhabited mountain, plateau and forest. It embraces the highest summits in the state, and at the same time the highest in eastern North America, except the White Mountains of New Hampshire and the Blue Ridge of North Carolina. Were it not for these two, even though the Appalachian region is decidedly and impressively mountainous, the Adirondacks would remain the loftiest summits in the east; and the equal of Mt. Marcy, called Tahawus or the Cloudsplitter' by the Indians, would not appear on the hither side of the Black Hills of South Dakota or the remoter Rocky Mountains. Geological Formations Present.-The Adirondack region in its geology presents an important and interesting series of Precambrian rocks. Roughly speaking, nearly the whole area consists of gneisses, but the metamorphic rocks can be separated into a great series of sedimentary gneisses, quartzites and coarsely crystalline limestones, on the one hand, and, on the other, into a second great series of eruptive syenites, granites and rocks of the gabbro family. Except for the limestones, all these rocks are hard and resistant, their weak points of attack being in a small degree their schistosity, and in a greater degree their joints. and faults. On all sides the Precambrian rocks are mantled with the Paleozoics, the oldest of which is the Potsdam sandstone of the Upper Cambrian,. a hard quartzite, gray, pink and pale yellow in color. The latest member of the Paleozoics having any association with the old crystallines is the Utica slate, near the top of the Ordovician, while between the Potsdam and the Utica appear in order from below, upward, the Beekmantown, Chazy and Trenton limestones. Except perhaps the Utica slate and the Trenton limestone, which is somewhat shaly, all these are firm, resistant rocks. The visible contacts of the Paleozoic strata with the old crystallines, especially on the northwest and west, are often those of sedimentary overlap, due to an advancing shore line, but on the east and northeast they are much more frequently due to blockfaulting of a most interesting character and exceedingly significant as throwing light on the physiography of the interior mountains. Aside from this, however, the Paleozoic strata enter only in a very minor way FIG. 2. MT. MCINTYRE, THE SECOND PEAK IN ALTITUDE-viewed from the southeast. The side towards the observer is very steep. into the structure of the mountains. They occur around the edges, except for a few isolated outliers from five to forty miles within the Precambrian area. After the deposition of the Utica, so far as the actual evidence is concerned, there were no more rocks laid down until the advent of the Labradorean ice sheet of the Glacial epoch. Whether later Paleozoics once existed and have been removed by erosion, or whether the area has been continuously land from the close of the Ordovician to the present, may be esteemed to a certain extent open to debate. From observations near Little Falls on the southern side, Professor H. P. Cushing has concluded that the Niagara limestone probably extended a long distance into the area of the crystallines if not entirely across. But no trace of it has been discovered in place, and the great gap in time from the Ordovician to the Glacial epoch must be interpreted, if at all, by the structural and physiographic records. The Labradorean ice sheet was, however, of enormous importance. Its deposits are heavy, and it doubtless operated to form numberless lakes and to greatly reorganize the drainage, as will be later pointed out in a few suggestive instances. The Mountains Proper and the Western Plateau.-The Adirondack region, sometimes referred to as the Great North Woods, is mountainous in its eastern half, and has its highest peaks near its center, but on the west the mountains disappear and the area becomes a plateau ranging from 2,000 feet above tide gradually downward to the west until it is but slightly higher than Lake Ontario and the St. Lawrence. The FIG. 3. MT. WHITEFACE FROM FRENCH'S HOTEL ON THE NORTH. Steep and narrow passes bound it on either side. loftiest peak is Marcy, 5,344 feet, and there are one or two others which exceed 5,000, together with five or six additional above 4,500, and many above 3,000. The mountains are ranged in visible northeast and southwest lines, and are often very steep if not positively precipitous in the portions that look to the southeast or northwest. There are also other steep faces nearly at right angles with the above, but they are less pronounced. When viewed from a distance the profile is strongly serrate -a gradual slope up on one side being cut off abruptly by an almost vertical descent on the other. The individual mountains are diversified in shape. Mt. Marcy is a very low cone, and the last stages of its ascent are very much like climbing a dome. Mt. McIntyre has a gradual slope from the northwest, |