CHAPTER I.
If the whole surface of Europe were to be depressed verti-cally about 500 yards, it would be changed from a continent intoseveral groups of mountainous islands. The loftiest and mostconspicuous among these would lie in a general direction fromE.N.E. to W.S.W., between the 43rd and 48th parallel of lati-tude ; with the exception of one long narrow spur, which wouldextend for many miles to the S.E. This group would be com-posed of the mountain chains now classed together under thegeneral title ‘ The Alps ’; the spur being the Apennines , whichat present form the backbone of central Italy and the southernboundary of the great Lombardo-Venetian plain, and are fusedwith the Maritime Alps at the head of the Gulf of Genoa. Itwould be bounded on the east by a narrow land-locked strait,now the valley of the Rhone and Saone . A still narrowerstrait, through which the former river at present escapes fromthe mountains, would cut it off from the long ridges of theJura ; and all along its northern face, protected here and thereby clusters of islets, and broken by fiords like the western coastsof Scotland or of Norway , would roll the broad waters of the,German Ocean. Its eastern extremity would sink down into an.