THE ICE AGE. 321 



to the ocean, reaching its maximum in Maine and the borders of Can- 

 ada ; while, as we retire from the margin of the States, we observe 

 that the scratches and grooves acquire a north-and-south direction, 

 becoming nearly meridional over New York, and then slowly swing 

 round to the west, until in Ohio, Indiana, Illinois, Missouri, and the 

 western limits of the continent, they lie pointing northeast and south- 

 west. Thus they assume a rudely-outlined radiation from the high- 

 lands of Canada, and stretch out from an hypothetical centre there 

 like the multiplied spokes of a great wheel. In Switzerland they 

 sweep down and out from the central ranges of the Alps in all direc- 

 tions, and, while locally uniform, they converge from the south, and 

 east, and north, and west, toward the lofty slopes and pinnacles of 

 this congeries of mountains. Over West Russia and Northern Europe, 

 where the markings are discovered, they indicate the Scandinavian 

 mountains to have been the seat of whatever disturbance or agency 

 has, at a distant period, fluted and engraved the continent; similarly, 

 as the rocks lie related to the Highlands of Scotland, the Lake Hills 

 of England, or the mountains of Wales, the striae impressed upon them 

 extend toward every point of the compass. They stream north and 

 south from the summits of the Pyrenees, from the peaks of the Cau- 

 casus, and down the valleys of the Himalayas. It must be under- 

 stood, however, that these conclusions are based upon an average of 

 the bearings of the grooves in each instance, and that these are infi- 

 nitely varied by the construction and irregularity of the land. 



Thus over greater portions of the world we find the rocks fur- 

 rowed, polished, and striated, in long, frequently deep and rectilinear 

 grooves, which lie in groups and series identical in direction, and 

 pointing to associated highlands, or distant continental mountain- 

 ranges, as the source of whatever strange and inexorable instru- 

 mentalities have produced them. Oyer New York Island the 

 gneissoid and granitic rocks, where they raise their tilted strata 

 and broken shoulders above the ground, are scored frequently with 

 deep and sinuous channels. In Central Park, along Fifty -ninth 

 Street, up the west side, the contorted and twisted humps of gneiss 

 are moulded in this way. Sometimes, where a rupture exists, and one 

 part of an outcrop has fallen below the other, the grooves are con- 

 tinued on the lower half; frequently the lines are crowded together 

 like rulings on a page, and again the groove is of irregular depth, its 

 floor rising and falling as though hitches had occurred when it was 

 first planed, the great chisel meeting resistance, or being thrown up 

 at points along its path. In the White Mountains the sides of the 

 mountains, the valleys, the top of Mount Washington, at 5,000 feet 

 above the sea, are all cut with these strange furrows, the rocks pol- 

 ished, and the whole country bearing these evidences of past erosion 

 wherever the naked rock meets the eye. Over Maine the same phe- 

 nomena present themselves in endless succession, the grooves striping 



VOL. XII. 21 



