Keyes — Meteorites on the Painted Desert. 147 



Bearing Upon Meteoritic Source of the Ores. 



In the consideration of the petrologic aspects of the 

 larger stony masses termed meteorites in the same man- 

 ner as that by which the igneous rocks of the globe are 

 examined, suggestive relationships are at once estab- 

 lished. They appear to have a very important bearing 

 upon the source of the ore materials. Of the four main 

 groups usually recognized among the common terrestrial 

 rocks of igneous origin the ultra-basic class is quite rare. 

 Among the stony meteorites the rock-species distin- 

 guished are not only largely ultra-basic in character but 

 the cosmical series begins with the most basic of the 

 earthly classes and continues through yet unnamed series 

 in which the metals form a large proportion of their 

 make-up. 



So long ago as 1871 Meunier 40 recognized nearly 50 

 lithologic types among the meteorites, of most of which 

 he later 47 described the microscopical characters and 

 among which he noted a wide range of metallic elements. 



The metals occurring in meteorites include nearly all 

 of those found in the common ores. Gold and silver are 

 the only conspicuous metals which do not yet appear to 

 exist abundantly in celestial minerals. There are, how- 

 ever, good grounds why these two metals have not been 

 reported; and other equally good reasons why certain 

 other metals seemingly occur only sparingly; so that the 

 apparent absence of some of these elements in the compo- 

 sition of known meteorites in no way precludes their de- 

 rivation from this source. 



In explanation of the notable difference in the relative 

 abundance of elements in terrestrial and sideral rocks 

 it is suggested by Farrington 48 that there are good 

 grounds for believing this unlikeness to be apparent 



ia Geol. des. Meteorites: Moniteur scient.ifique Quesneville, 1 et 15 

 fevrier. 1871. 



"Bull. Soc. d'Hist. nat. d'Autun. 16. 1893; and Ibid. 17. 1895. 

 4S Journ. Geol. 9:394. 1901. 



