478 COSMOS. 



which were contributed by me and 20 by Boussingault. 10 * 

 In the basalt formations of the jN"ew World, olivine along 

 with augite is as abundant as in Europe ; but the black, ba- 

 saltic trachyte of Yana Urcu, near Calpi at the foot of the 

 Chimborazo, 1 as well as those enigmatical trachytes called la 

 reventazon del volcan de Anzango, 2 contain no olivine. It was 

 only in the great, brown-black lava-stream, with a crisp, 

 scoriaceous surface raised like a cauliflower, whose track 

 we followed in order to reach the crater of the volcano of 

 Jorullo, that we met with small grains of olivine imbedded. 3 

 The prevailing scarcity of olivine in the modern lavas and 

 the greater part of the trachytes seems less striking when we 

 recollect that, essential as olivine appears to be for basalt in 

 general, yet (according to Krug von Nidda and Sartor ius 

 von Waltershausen) in Iceland and in the German Rhone 

 Mountains the basalt destitute of olivine is not distinguish- 

 able from that which abounds in it. The former it has been 

 the custom from the earliest times to call trap and waclce, the 

 latter we have in modern times denominated Anemasitc^ 

 Olivines, which sometimes occur as large as a man's head in 

 the basalts of Rentieres in the Auvergne, attain also in the 

 Tinkler quarries, which were the object of my first youthful 

 researches to the size of 6 inches in diameter. The beautiful 

 Jrypersthene rock of Elfdalen in Sweden, much employed 



100 A considerable portion of the minerals collected during my Ame- 

 rican Expedition, has been sent to the Spanish Mineral Cabinet, to the 

 King of Etruria, to England and to France. I do not refer to the geologi- 

 cal and botanical collections which my worthy friend and fellow-labourer 

 Bonpland possesses, with the twofold right of self-collection and self- 

 discovery. This extensive dispersion of the materials, (which, from the 

 very exact account given of the places in which they originated, does 

 not prevent the maintenance of the groups in their geographical rela- 

 tions,) has this advantage that it facilitates the most comprehensive and 

 exact definition of those minerals whose substantial and habitual asso- 

 ciation characterises the different kinds of rocks. 



1 Humboldt, Kldnere Schriften, Bd. i, s. 139. 



2 Ibid, s. 202, and Cosmos, see ab^ve, p. 232. 



3 Humboldt, Kl. Schr. vol. i, p. 344. I have also found a great deal 

 of olivine in the Tezontle (cellular lava, or basaltic amygdaloid ? in 

 Mexican, tetzontli, i.e., stone-hair, from tetl, stone, and tzontli, hair) 

 belonging to the Cerro de Axusco in Mexico. 



4 Sartorius von Waltershausen, Physisch-ycographische kizze von 

 Island, s. 64. 



