I do not wonder that, when the sceptic stands upon the banks of Niagara River, and sees how obviously the splendid cataract has worn out the deep gorge extending to Lake Ontario, he should feel that there is a standing proof that the common opinion, as to the age of the world, cannot be true; and hence be led to discard the Bible, if he supposes that to be a true interpretation. But the Niagara gorge is only one among a multitude of examples of erosion that might be quoted; and some of them far more striking to a geologist. On Oak Orchard Creek, and the Genesee River, between Rochester and Lake Ontario, are similar erosions, seven miles long. On the latter river, south of Rochester, we find a cut from Mount Morris to Portage, sometimes four hundred feet deep. On many of our south-western rivers we have what are called _canyons_, or gorges, often two hundred and fifty feet deep, and several miles long. Near the source of Missouri River are what are called the Gates of the Rocky Mountains, where there is a gorge six miles long and twelve hundred feet deep. Similar cuts occur on the Columbia River, hundreds of feet deep, through the hard trap rock, for hundreds of miles, between the American Falls and the Dalles. At St. Anthony's Falls, on the Mississippi, that river has worn a passage in limestone seven miles long, which distance the cataract has receded. On the Potomac, ten miles west of Washington, the Great Falls have worn back a passage sixty to sixty-five feet deep, four miles, continuously--a greater work, considering the nature of the rock, than has been done by the Niagara. The passage for the Hudson, through the highlands, is probably an example of river erosion; as is also that of the Connecticut at Brattleboro' and Bellows Falls. In these places, it can be proved that the river was once at least seven hundred feet above its present bed. On the Deerfield River, a tributary of the Connecticut, we have a gulf called the _Ghor_, eight miles long and several hundred feet deep, cut crosswise through the mica slate and gneiss by the stream.