24 Field Columbian Museum — Geology, Vol. i. 



cally in an amorphous or crypto-crystalline ground. The occurrence 

 and association of these minerals is similar to that in the eruptive 

 rocks of the earth, and these they closely resemble. Representatives 

 of many of the different varieties of eruptive rocks can indeed be 

 found among the aerolites, so that, in the view of Wadsworth, no 

 distinctions in classification should be made between rocks of terres- 

 trial and extra-terrestrial origin if they resemble one another in con- 

 stitution. Thus the aerolites containing no feldspar and made up 

 chiefly of chrysolite are classed by him with the peridotites, the dif- 

 ferent varieties finding representatives as follows: — Dunite, a rock 

 made up chiefly of chrysolite and chromite, is represented by the 

 meteorite of Chassigny; saxonite, composed of chrysolite and ensta- 

 tite, by those of Homestead (313) Knyahinya (284) and Waconda (389) ; 

 lherzolite, made up of chrysolite, enstatite and diallage, by those of 

 Pultusk (289) and New Concord (274). 



Similarly the aerolites containing feldspar may be considered as 

 corresponding to the basalts and gabbros in mineralogical constitu- 

 tion ; basalt, made up of augite and anorthite, finding a representative 

 in the stones of the Stannern (225) fall; gabbro, composed of anor- 

 thite and enstatite, in the meteorite of Juvinas (237). 



While such a grouping is convenient for keeping in mind the 

 mineral constitution of the different aerolites, it is doubtful whether 

 its application should be pushed much farther, since the distinction 

 of origin is one of considerable importance. 



The classification suggested b}' Tschermak* for the aerolites is 

 as follows : 



I. Aerolites made up of chrysolite and bronzite with iron subor- 

 dinate, texture mostly chondritic. (L'Aigle, Knyahinya, New Con- 

 cord, Pultusk, etc.) 



II. Aerolites made up chiefly of chrysolite or bronzite or other 

 pyroxene. 



(a) Chassignite, composed mostly of chrysolite. (Chassigny.) 



(b) Amphoterite, composed of chrysolite and bronzite. (Man- ' 

 bhoom.) 



(c) Diogenite, composed of bronzite or hypersthene. (Ibben- 

 buhren, Shalka.) 



(d) Chladnite, composed of enstatite. (Bishopville). 



(e) Bustite, composed of diopside and enstatite. (Busti). 



III. Aerolites made up of augite, bronzite, and lime feldspar and 

 having a shining crust. 



(a) Howardite, composed of augite, bronzite and plagioclase, 

 (Frankfort, Lontolaks.) 



(b) Eukrite, composed of augite with anorthite or maskelynite. 

 (Juvinas, Jonzac, Stannern, Peterborough.) 



*Ber. Ak. Wien., Bd. 88, pp. 347, 371. 1883. 



