NOTES. 



upper oolite. Compare my Essai ge'ogn. sur le Gisement des Roches, 1823, 

 p. 281. 



( G09 ) p. 436. The name of Andesite was first printed in a memoir of 

 Leopold von Buch's, read at the Berlin Academy on the 26th of March 1835. 

 As that great geologist restricted the name of trachyte to rocks in which glassy 

 felspar is contained, he said in his memoir read to the Academy in. March 1 835, 

 but not published until 1836 (Poggend. Ann. Bd. xxxvii. S. 188190): 

 " The discoveries of Gustav Eose on felspar have thrown a new light on volca- 

 noes and the whole of geognosy, and the kinds of rock in volcanoes have appeared 

 thereby in a new and entirely unexpected aspect. After many careful examina- 

 tions in the district about Catania, and on Etna, we, '. e. Elie de Beaumont and 

 I, became convinced that there is no felspar in Etna, and therefore no trachyte. 

 All the streams of lava, as well as the beds in the interior of the mountain, 

 consist of a mixture of augite and labradorite. Another important difference in 

 the rocks of volcanoes appears when albite takes the place of felspar; a new 

 rock is thus constituted which can no longer be termed trachyte. According to 

 G. Rose's investigations (at that time), it may be affirmed almost decidedly that 

 not one of the numerous volcanoes of the Andes consists of trachyte; but that 

 they all contain, in the mass of which they are formed, albite. Such an asser- 

 tion seems a very bold one; but it will appear less so if we consider that almost 

 the half of these volcanoes, and their products in either hemisphere, are known 

 to us by Humboldt's travels alone. Further, this kind of rock, rich in albite, is 

 known through Meyen in Bolivia and the north of Chili, through Pb'ppig to the 

 extreme south of Chili 5 as well as through Erman in the volcanoes of Kam- 

 tschatka. Such a marked and widely extended prevalence seems sufficient to 

 justify the name of andesite, by which this kind of rock, consisting of predomi- 

 nating albite mixed with a little hornblende, has been already more than once 

 presented to notice." Almost at the same time, in the additions with which, in 

 1836, he so materially enriched the French edition of his work on the Canaries, 

 Leopold von Buch entered into still further details; considering the volcanoes 

 Pichincha, Cotopaxi, Tungurahua, and Chimborazo all to consist of andesite; 

 and, on the other hand, calling the Mexican volcanoes true (sanidine-containing) 

 trachytes ! (Description physique des lies Canaries, 1836, p. 486, 487, 490. 

 and 515.) The lithological classification of the Mexican and Andes volcanoes 

 which has been given in this work, shows that there is no such uniformity of 

 inirieralogical constitution, and that no general designation, taken from an ex- 

 tensive region of the earth, can be scientifically applicable. Not long afterwards, 

 I also twice committed the fault of employing the name of andesite, the use of 

 which tends to create confusion: once, in 1836, in the description of my attempt 



