MEMOIE OF LEOPOLD VON'bUCH. ■ 369 



pier manner. By reversing the fact and presenting it as it really occurred, the 

 explanation at once presents itself and changes the face of the science. 



With Von Buch it was inevitable that one discovery slioiild lead to others. 

 Thus, a first view reveals to him the upheaval of mountains and that of conti- 

 nents ; a second, the mechanism of the formation of volcanoes ; a third, the re- 

 lation which connects the displacement of seas with the elevation of mountains. 

 One of his most prolific views, that of the discordance of rocks, disclosed to 

 our distinguished colleague, M. Elie de Beaumont, (a geologist who, by his own 

 labors, has united the researches of Cuvier with those of Von Buch,)* the first 

 germ of his learned theory of the relative age of mountains. We owe still an- 

 other highly ingenious and novel concep-tion to Von Buch. His explanation 

 of the formation of dolomite, f or, more generally, of the alteration produced on 

 deposited and sedimentary rocks by. the incandescent rocks of elevation which 

 have traversed them, though still subject to some difficulties,! must always be 

 looked upon as an indication of a high order, and as having marked out for 

 modern geology one of its most important objects, the study of the secondary 

 action of fire on the envelope of the globe. 



After so many brilliant labors, the smiling banks of the Spree, with the re- 

 turn of every autumn, continued to recall this eminent and indefatigable man 

 to the quiet retreat which he had chosen. There, a simplicity, the more charm- 

 ing as it was wholly voluntary, presided over the economy of his daily life. 



t " Ciivier has shown that the surface of the globe has undergone a succession of sudden 

 and violent revolutions. Leopold von Buch has indicated detinite and marked differences 

 between the several systems of mountains which diversify the surface of Europe. I attempt 

 nothing but to bring into relation these two orders of ideas." — Elie de Beaumont : Reclierches 

 sur qudques-unes des revolutions de la surface du globe. 



t By the formation of dolomite, Von Buch designs more precisely the change of calca- 

 reous shell-bearing stone into calcareous magncsian stone. 



" How-comes it that tlie magnesia can pierce, traverse, change the nature of the calcareous 

 beds, which are many thousand feet in height, to make of them a rock uniform in its whole 

 extent? It is acpiestion which I have proposed to myself in all my excursions in the neio-h- 

 borhood of the valley of Fassa, without finding a solution. The calcareous stone does not 

 contain magnesia. It comes, then, from another quarter, and it is quite natural to believe 

 that it is the pyroxene which furnishes it, since magnesia is one of the constituent parts of 

 this substance. I think I have discovered, in the environs of Trento, the process of nature in 

 this operation, and this process has appeared to me so evident that at the instant of the ob- 

 seivatiou I experienced the most lively satisfaction which 1 have ever felt in my excursions 

 across the Alps." — Lettre d M. de Humboldt, Sec. 



" We can easily conceive that a mountain rent and fissured must lose every appearance of 

 beds ; that thousands of channels arc opened for the magnesia to introduce itself and com- 

 bine with the calcareous rock ; that by little and little all the mass must change into rhombo- 

 hedrons ; and it is in this way that compact beds, filled with shells, may change into a mass 

 uniform, white, granular, and saccharoidal, without a vestige of organized bodies or any hor- 

 izontal lissures whatever " — Ibid. 



"This splitting recalls the phenomena which may be daily observed in limestone furnaces 

 when the fire is withdrawn from them. In going from Cortina, in the valley of Ampezzo, to 

 Toblacli, iu the Pusterthal, one is surrounded, during the whole transit, by peaks of dolo- 

 mite. The aspect of these places is so singular that we might think ourselves transported 

 into the midst of an immense furnace. The fragments of dolomite are traversed by immense 

 clefts ; they appear rough to tlie touch, like all substances exposed to the fire. One is 

 tempted to attribute these extraordinary effects to the high temperature which the pyroxenic 

 porphyry had acquired when it penetrated through the inferior strata, and lifted up the dolo- 

 mite in the form of columns, pyramids, and towers. I am persuaded that this same pyrox- 

 enic rock has converted the compact masses into granular masses, that it has caused the dis- 

 appearance of every vestige of stratification and of organized bodies, and that it has given 

 rise to those fissures which are strewn with crystals. We can no longer doubt that it is the 

 compact limestone, which is constantly found uuder the dolomite and above the sandstone, 

 that has been whitened, fissured, and transformed into a granulated rock." — Lettre sur la 

 dolomie du Tyrol d M. Alois de Pfaundler . 



t On these difiiculties, see the important and ingenious labors of MJI. Ilaidiuger and 

 Morlot. [The subject will be found also elaborate!ly discussed in the article on the meta- 

 morphism and crystallization of rocks, by Mr. Daubree, translated for and published in the 

 Smithsonian report for 1861.] 



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