58 G. F. Kunze—Meteoric Iron from Virginia. 
same chemical composition, and that the granular rocks as a 
group have been less intensely heated than the porphyries. 
It is well known to those who are likely to read the fore- 
going pages, that Messrs. Hague and Iddings have drawn 
very different conclusions* from a study of my collections 
from the neighborhood of the Comstock lode; and, that they 
have disputed many of the results both lithological and struct- 
ural reached in my memoir on that great ore-deposit.t I have 
replied to their conclusions elsewhere ;{ but I may be per- 
mitted to repeat here, that I have re-examined the district and 
mines with their paper in hand and am only the more con- 
vinced that my elucidation was substantially correct. The 
diorite, diabase and augite andesite are not a single eruption or 
series of eruptions, as they maintian; but constitute three and 
_ probably four eruptions which took place at long intervals of 
time. ‘There is very strong evidence that the diorite and dia- 
base are pre-Tertiary rocks both at the Comstock and that 
Steamboat Springs, six miles distant, where diabase pebbles are 
included in metamorphic conglomerates of pre-Tertiary (prob- 
ably Jura-Trias) periods. The earlier hornblende andesite of my 
report is intermediate in age between the diabase and the augite 
andesite. ‘The quartz porphyry is pre-andesitic, orthoclastic 
and does not intersect the Sutro tunnel. The Washoe district 
presents no valid argument for asserting a progressive increase 
of crystallization in the rocks, while it offers the strongest argu- 
ments in favor of the conclusions drawn in this paper. 
‘U.S. Geological Survey, Washington, D. C., Oct. 1886. 
Art. VIL—A fifth mass of Meteoric Iron from Augusta Oo., 
Va.; by GEorGE FI. Kunz. 
THIS mass of meteoric iron was given to the late Colonel 
W. B. Baldwin, of Staunton, Augusta Co., Va., and was found 
at or near the place where the largest of the three masses from 
Augusta Co., first described by Professor Mallet,$ was found. 
Col. Baldwin was under the impression that it was a detached 
part of the largest mass. Professor Mallet received it from 
him ata considerably jater date than the large mass, and having 
chipped and filed a small flat surface, he found, after etching, 
that the Widmanstatten figures were like those on the large 
mass. A careful examination satisfied him that this piece of 
iron had not been in any way artificially detached from any one 
* Bull. U. S. Geol. Sur., No. 17. 
+ Geology of the Comstock Lode, ete., U. S. Geological Survey, Monograph III. 
t Bulletin of the California Academy of Sciences, No. 6, p. 93. 
§ This Journal, III, ii, 10, 1871. 
