90 



PHYSICAL GEOGRAPHY— THE LAND. 



the lapse of 12,000, if the motion prove contin- 

 uous and equable, parts of the bottom of the 

 ocean that lie near the peninsula, and at the 

 present day are covered M^ith 100 feet of wa- 

 ter, and more, will have come to the surface, 

 and begun to be laid dry. But what is the 

 brevity of these intervals compared with the 

 length of the geological periods, which the suc- 

 cession of strata in the several formations, 

 and the host of extinct and totally different or- 

 ganisms which they inclose, reveal to us ! We 

 have here considered the phenomenon of up- 

 heavement only ; but we can readily, resting 

 on the analogies of facts observed, in like meas- 

 ure figure to ourselves the possibility of the 

 sinking or submersion of whole districts of 

 country. The mean height of the level, or 

 non-mountainous portions of France is not 

 quite 480 feet. Contrasted with former geo- 

 logical periods, in which more extensive chan- 

 ges went on in the interior of the earth, we 

 perceive that no very long period of time were 

 requisite to have considerable portions of the 

 north-west of Europe permanently overflowed, 

 and presenting in its sea-board a very different 

 outline from that which now distinguishes it. 



Risings and fallings of the solid, or of the fluid 

 — in their several effects so evenly balanced 

 that the rise of the one occasions the seeming 

 fall of the other — are the cause of every change 

 in the configuration of continents. In a gener- 

 al Picture of Nature, in a liberal, not one-sided, 

 presentment of the phenomena of nature, the 

 possibility at least of a diminution in the mass 

 of waters, of a true sinking in the mean sea- 

 level, must therefore be indicated. That with 

 the former high temperature of the surface of 

 the earth, with the greater water-engulfing 

 fissuration of its crust, with a totally different 

 constitution of its surrounding atmosphere, 

 great variations in the level of the sea may 

 have taken place in connection with the in- 

 crease or decrease of the liquid element, there 

 is no room left for doubt. In the actual condi- 

 tion of our planet, however, we are totally with- 

 out any direct evidence of an actual progressive 

 decrease or increase of the sea ; we are also 

 without any proof of change in the mean height 

 of the harometer at the sea level of the same 

 points of observation. From Daussy's and An- 

 tonio Nobile's researches, it appears that an in- 

 crease in the height of the barometer would of 

 Itself be accompanied with a depression of the 

 sea-level. But as the mean pressure of the at- 

 mosphere at the level of the sea, in consequence 

 of meteorological causes — direction of the wind, 

 moistness of the air — is not the same under ev- 

 ery parallel of latitude, the barometer of itself 

 can supply no certain evidence of change in the 

 liquid level of our globe. The remarkable phe- 

 nomenon which was observed in the beginning 

 of the present century, when several harbours 

 of the Mediterranean were repeatedly left com- 

 pletely dry for many hours, appears to indicate 

 that alterations in the direction and strength 

 of currents, without any actual diminution in 

 the quantity of water, without any general de- 

 pression of the level of the ocean, may give 

 rise to local recessions of its waters, and to 

 permanent exposures of small portions of its 

 shores. From the knowledge lately obtained 

 of these complicated phenomena, it seems that 



we must be particularly cautious in interpret- 

 ing them, inasmuch as effects may very readily 

 be ascribed to one of the " old elements," the 

 water, which belong of right, and in fact, to 

 two others, the earth and the air. 



As continents, which we have hitherto delin- 

 eated in their horizontal extension, by their 

 configuration, by their external distribution and 

 their variously indented coasts, exert a benefi- 

 cial influence upon climate, commerce, and the 

 progress of civilization, so is there another kind 

 of internal subdivision effected by perpendicu- 

 lar elevations of the surface — by mountain 

 chains and lofty table lands — which have con- 

 sequences that are not less important. All 

 that occasions change, variety of form and fea- 

 ture, in the surface of the planet — the dwell- 

 ing-place of the human family — besides mount- 

 ain chains, great lakes, grassy steppes, and 

 even deserts surrounded by wooded regions as 

 by coasts, impresses a peculiar character on 

 communities. Lofty ridges covered with snow 

 interrupt communication, interfere with traffic ; 

 but a mixture of less elevated mountain mem- 

 bers lying apart(^'**), and of low lands, such as 

 the West and South of Europe, present in such 

 happy interchange, occasion variety in the me- 

 teorological processes, as well as in the prod- 

 ucts of the vegetable kini^dom ; and further be- 

 get wants, as every district even under the 

 same degree of latitude then falls under the 

 dominion of a different kind of husbandry, the 

 satisfaction of which arouses the activity of the 

 inhabitants. Thus have the dreadful convul- 

 sions that have ensued upon the reactions of 

 the interior against the exterior, upon sudden 

 upheavals of portions of the oxidized crust of 

 the earth, upon the elevation of vast mountain 

 chains, still proved conducive, with tranquillity 

 restored, with the revival of the slumbering 

 might of the organizing forces, to cover the dry 

 land of either half of the globe with a beautiful 

 abundance of individual forms, and to free at 

 least the greater portion of it from the blank 

 of uniformity which appears to cramp and im- 

 poverish both the physical and the intellectual 

 powers of man. 



To each system(3") of these mountain chains 

 there is, according to the grand views of Elie 

 de Beaumont, a relative age to be assigned : 

 the upheaval of the range must necessarily fall 

 between the times when the erupted strata 

 were deposited, and those in which the hori- 

 zontal beds, that stretch up to the very foot of 

 the mountains, were laid down. The furrow- 

 ings of the crust of the earth, in other words, 

 the erections of strata which are of like geo- 

 logical age, appear, moreover, to attach them- 

 selves to one and the same direction. The 

 line of strike, or heaving of the strata, is not 

 always parallel to the axis of the chain, but 

 sometimes cuts it through ; so that, according 

 to my views(3='^), the phenomenon of erection 

 of strata which is even found repeated in the 

 neighbouring level, must be older than the ele- 

 vation of the chain. The principal direction 

 of the whole of the dry-land in Europe (south- 

 west to north-east) is opposed to the great fis- 

 sure or valley which runs from north-west to 

 south-east, from the mouths of the Rhine and 

 the Elbe, through the Adriatic and Red Sea, 

 across the mountain system of Puschti-Koh in 



