CHAPTEK IT. 



THE SIDEROLITES AND PALLASITES. 



Sectio]^" I. — SideroUlc. 



In" this, the first or most basic, species or group, the rock is composed 

 chiefly of iron — either native or in its secondary states, as magnetite, 

 liomatite, menaccanite, etc. — and with or without nickel, schreibersite, 

 ]iyrrhotite, graphite, etc. 



It inchides all those masses of iron and iron ore that have fallen as 

 meteorites, or which formed an original, not secondary, portion of the earth, 

 or are of eruptive origin, or directly derived, as fragmental deposits, from 

 any of these. No veins or chemical deposits of iron ore are intended to be 

 nicluded in this species. 



The characters of the supposed meteoric siderolites have been so fully 

 described in numerous papers and treatises on the subject, that it is not 

 necessary to describe them here in any detail. A few specimens only will 

 be spoken of below, that the writer has seen, which will give a few of the 

 characteristics. 



In such meteoric siderolites as that from Shingle Springs, Eldorado 

 Co., California, the iron is in a nearly homogeneous mass, since only two 

 small masses of pyrites have been reported to have been found in it. 

 The etched surface of a specimen in Professor Whitney's collection shows 

 an oljscure granular structure, which under the lens is seen to be formed 

 by some brilliant points, and small elongated ridges of like bright metallic 

 lustre, rising above the dull gray surface left by the acid. 



Professor B. Silliman states of a specimen in his possession that the 

 etched surface showed under a lens " a reticulated structure with numerous 

 brilliant points and v-shaped lines." * 



The meteoric siderolite from Stanton, Augusta Co., Virginia, is a very 



* Amcr. Jour. Sci., 1S73 (3), vi. lS-22. 



