I2 NEW YORK STATE MUSEUM 
tions which were being conducted near Hackettstown, says: “ Ore 
has been uncovered in many places, but in most instances it has been 
found as a constituent mineral of granitic and syenitic dykes — more 
rarely in gneissic strata.” (p. 17) 
Smock thought that while such rock masses might be closely 
related to ore beds, it was improbable that they would lead to beds 
or veins of commercial value; the significance of their occurrences 
totally escaped him, for, in the following year, in the report for 
1873," he says: “ The greater portion of the Azoic rock is syenttic 
gneiss, being composed of crystalline grains of quartz, feldspar and 
hornblende, like syenite, and being stratified like a true gneiss” 
p. 17), and as to the origin of the rocks of this formation he says: 
“The rocks of this (Azoic) formation are now conceded by all 
geologists to be of sedimentary origin. They were originally de- 
posited from water as sand, earth, clay, shells, and corals or marls, 
and oxide of iron.” (p. 19) 
Very little of additional interest or importance was contributed to 
the literature on the geology of the Highlands until 1880; and indeed, 
so far as the Highland area in southeastern New York is concerned, 
a literary hiatus exists between Mather’s last report in 1843 and the 
Tenth Census report of 1880.° This report, covering both coal and 
iron, was issued by the Department of the Interior, and contains the 
results of “special investigations into the iron resources of the 
Republic.” B. T. Putnam was the author of that portion of the 
report dealing with the iron-ore mines of New York. Putnam con- 
fined himself to a discussion of the operation, production, location, 
quality of the ore and extent of workings of the mines then operating, 
with but brief reference to the forms of the ore bodies and the nature 
of their associated rocks. He did not speculate on the origin of 
the magnetites and did not discuss the general geology of the area 
in which they occur, as indeed this phase of the situation was 
beyond the scope of his paper. While the Tenth Census report bears 
the date of 1880 it did not see the light of day until 6 years later; 
in the meantime James D. Dana,*® who had been making a lengthy 
study of Green Mountain geology, extended his investigations into 
14 Annual Report of the State Geologist of New Jersey for 1873. 
15 Report on the Mining Industries of the United States. Tenth Census, 
1880. The Tenth Census report was not published until 5 or 6 years after 
the census year, however. 
16 Dana, James D. Geological Relations of the Limestone Belts of West- 
chester County, New York. Am. Jour. Sci., 3d ser., 20: 21-32, 194-220, 
450-56, 1880. Idem. 21: 425-43, 1881, and 22: 103-19, 313-15, 327-35, and 
appendix, 1881. 
