A theory which appears to be in perfect harmony with the facts to account for the subsidence and partial reelevation of central eastern North America and Scandinavia since the beginning of the Ice Age is that the great weight of ice during the Ice Age pressed the land down, and that since the removal of the ice there has been an appreciable tendency for the land to spring back. Certain crustal movements which have occurred about the Bay of Naples are of very special interest because actual human history dates can be placed upon them. Most remarkable are the records in connection with the temple of Jupiter Serapis which was built near the shore before the Christian era. The land sank about five feet and a new pavement had to be constructed; then, by the middle of the third century A. D., the temple rose to well above sea level. By about the ninth century the land had subsided fully thirty feet, so that marble columns of the temple were bored full of holes as high as twenty-one feet above their bases by marine-shelled animals, species of which still live in the bay. Then a slow uplift of twenty-three feet began, bringing the bases of the columns two feet above sea level by 1749. Since that time a slight sinking has taken place and this seems to be still going on. Three of the marble columns with the borings still stand in upright position. While the movements just described were taking place, the island of Capri, twenty miles across the Bay of Naples, has slowly sunk to an amount estimated at thirty or forty feet as proved by evidence from the famous Blue Grotto. About the beginning of the Christian era a large ancient wave-cut cave, part of which is now called the Blue Grotto, had its floor above sea level, and it was used by certain Romans as a cool place to retire to from the heat. In order to obtain better light an opening was cut through its upper portion. The land has sunk so much that at the present time even part of the artificial opening (through which tourists pass) is now under water. By way of illustrating remarkable contrasts in direction of crustal movements on very considerable scales in a given region, we shall briefly mention some facts regarding part of the coast of southern California and the neighboring islands of Santa Catalina and San Clemente, respectively twenty-five and fifty miles offshore. Those movements were not, however, checked up by human history records. The mainland at San Pedro has clearly risen 1,240 feet, as proved by the presence of unusually perfect coast terraces (so-called "raised beaches"), while San Clemente has risen 1,500 feet as proved by the raised beaches into which deep, youthful V-shaped stream-cut valleys have been sunk, and a shore line characteristic of recent notable uplift. It is a remarkable fact that at the same time the intervening island (Santa Catalina) has notably sunk, as proved by the nature of its shore line, and the distinctly more mature character of its topography.