About a thousand million years ago, a continent of unknown dimensions was rifted apart, creating an ancestral ocean more or less where the Atlantic is now. The older ocean has been called Iapetus, because Iapetus was the father of Atlas, for whom the Atlantic is named. Some geologists, who may feel that tl1eir science is dangerously clever, are snappish about Iapetus. They prefer to say protoAtlantic. The ancestral ocean existed a great ·deal longer than the Atlantic has, but gradually, across some two hundred and fifty million years in the Paleozoic era, it closed. Moving toward each other, the great landmasses on either side buckled and downwarped the continental shelves and then came together in a crash no less brutal than slow-a continent-to-continent collision marked by an alpine welt, which has reached its old age flexplek huren eindhoven as the Appalachian Mountains. In the Mesozoic era, two hundred and ten million years ago, rifting began again, pulling apart certain segments of the mountain chain, creating fault-block basins-remnants of which are the Connecticut River Valley, central New Jersey, the Gettysburg battlefields, the Culpeper Basin-and eventually parting the earth’s crust enough to start a new ocean, which is now three thousand miles wide and is Detail from “Delaware Water Gap,” by George Innes, z859. Collection of the Montclair Art Museum still growing. Meanwhile, a rhythm of glaciation has been established in what is essentially the geologic present. Ice sheets have been forming on either side of Hudson Bay and have spread in every direction to cover virtually all of Canada, New England, New York, and flexplek huren rotterdam much of New Jersey, Pennsylvania, and the Middle West. The ice has come and gone at least a dozen times, in cycles that seem to require about a hundred thousand years, and, judging by other periods of glaciation in the earlier history of the earth, the contemporary cycles have only begun. About fifty more advances can be expected. Some geologists have attempted to isolate the time in all time that runs ten thousand years from the Cro-Magnons beside the melting ice to the maternity wards of the here and now by calling it the Holocene epoch, with the implication that this is our time and place, and the Pleistocene-the “Ice Age” -is all behind us. The Holocene appears to be nothing more than a relatively deglaciated interval. It will last until a glacier two miles thick plucks up Toronto and deposits it in Tennessee. If that seems unlikely, it is only because the most southerly reach of the Pleistocene ice fields to date stopped seventy-five miles shy of Tennessee.