XIII.] ORIGIN OF CRYSTALLINE ROCKS. 287 



The doctrine of pseudomorphism by alteration, as taught by 

 Gustaf Rose, Haidinger, Blum, Yolger, Rammelsberg, Dana, 

 Bischof, and many others, leads them, however, to admit still 

 greater and more remarkable changes -than these, and to main- 

 tain the possibility of converting almost any silicate into any 

 other. Thus, by referring to the pages of Bischof 's Chemical 

 Geology, it will be found that serpentine is said to exist as a 

 pseudomorph after augite, hornblende, chrysolite, chondrodite, 

 garnet, mica, and probably also after labradorite and even 

 orthoclase. Serpentine rock or ophiolite is supposed to have 

 resulted, in different cases, from the alteration of hornblende- 

 rock, diorite, granulite, and even granite. Not only silicates of 

 protoxides and aluminous silicates are conceived to be capable 

 of this transformation, but probably also quartz itself ; at least 

 Blum asserts that meerschaum, a closely related silicate of 

 magnesia, which sometimes accompanies serpentine, results 

 from the alteration of flint ; while according to Rose, serpen- 

 tine may even be produced from dolomite, which we are told 

 is itself produced by the alteration of limestone. But this is 

 not all, feldspar may replace carbonate of lime, and carbon- 

 ate of lime, feldspar ; so that, according to Volger, some gneis- 

 soid limestones are probably formed from gneiss by the sub- 

 stitution of calcite for orthoclase. In this way, we are led 

 from gneiss or granite to limestone, from limestone to dolomite, 

 and from dolomite to serpentine, or, more directly, from gran- 

 ite, granulite, or diorite to serpentine at once, -without passing 

 through the intermediate stages of limestone and dolomite, till 

 we are ready to exclaim in the words of Goethe, 



" Mich angstigt das Verfangliche 

 Im widrigen Geschwatz, 

 Wo Nichts verharret, Alles flieht, 

 Wo schon verschwvmden was man sieht/'* 



which we may thus translate : " I am vexed with the sophistry 

 in their contrary jargon, where nothing endures, but all is 

 fugitive, and where what we see has already passed away." 



Chinesisch-Deutsche Jahres und Tages-Zeiten, XI. 



