INTRODUCTOIIY. Ho 



rated as a variety, the same as the ohvine-enstatite-diallagc ones have been 

 erected into the variety IherzoHte. Beheving, as he does, that the same 

 methods, rules, and principles should be employed in studying meteorites 

 as those used for the terrestrial rocks, and that both classes are in reality 

 the same, it follows that the same name should be used for both, and the 

 differences expressed adjectively if necessary. 



In accordance with this, the variety of peridotite distinguished by olivine 

 should, both as meteorites and terrestrial rocks, be designated by the term 

 already in common use for the latter — dunile. For that variety which con- 

 tains olivine and enstatite, the German term enstatit-oUvinfcls employed by 

 Dr. Dathe is too cumbersome for Anglo-Saxon use, or even for any general 

 use. It is, then, proposed here to designate all these rocks by the term 

 saxonite, from the country in which the terrestrial form was tirst so well 

 described by Dathe. 



The term IherzolUe is here applied to those rocks characterized by ensta- 

 tite, diallage, and olivine. The forms that are characterized by the presence 

 of olivine, enstatite (bronzite), and augite, are designated by the term buch- 

 nerite, given in honor of Dr. Otto Buchner, to whose writings on meteorites 

 we are so much indebted, and who gave the first description of a meteorite 

 having this composition. 



The term enhjsite is employed for the olivine-diallage forms, and picrite for 

 the olivine-augite variety. Of course, for all of the highly altered forms for 

 which the term serpentine has been already used, that name is retained ; but 

 in many cases, when it is known from what special variety the serpentine 

 has been produced by alteration, it has been described under that variety in 

 order to show its relations. This has particularly been the case with forms 

 coming from the same rock in a single locality, but showing different 

 stao;es of alteration. The fragmental forms, of which ouh a few have been 

 described, are classed under the term porodlte * for the old and altered forms, 

 and tufa for the unaltered. Thus far, in meteorites, the fragmental rocks are 

 all tufas, and in the terrestrial peridotites, porodites. 



* Bull. Mas. Comp. Zool., 1879, v. 280. 



