This finds further confirmation in the fact that the noted non-volcanic regions which are seriously shaken are all coincident with or adjacent to regions of extinct fires; while in such regions as are very seldom shaken, such as Germany, portions of North America, Brazil, the eastern slope of the Andes, the traces of such agency are less common, or of older date. Noted regions of volcanic action of comparatively recent extinction are Asia Minor, Turkey, Spain, Southern France and Greece. These, belted together by the active regions of Western Asia, the peninsula of Arabia, the Mediterranean, and Azores and Canaries, form a region which has suffered from earthquakes as much as, if not more than, any other tract upon the globe. Those who have been puzzled by the appearance of earthquakes some distance from any actively volcanic region, have endeavored to divide earthquakes into two classes, which they have called volcanic and plutonic. This second class they have considered as originating, like the other, in the depths of the earth; but have endeavored to account for them by supposing them to be occasioned by the falling in of great caverns at a considerable depth. This theory has found a fair objection in the fact that in such cases an earthquake should always be a sinking of the ground: while the wrecking power and peculiarities of some earthquakes indicate a decided upward concussion as the first of shocks; and at the seashore, where any change in level is at once detected, upheaval is quite as common as subsidence.