36 CORUNDUM IN THE UNITED STATES. [bull. 180. 
CORUNDUM IN LIMESTONE. 1 
Extending from Byram, Sussex County, N. J., to Warwick Town- 
ship, New York, a distance of about 25 miles, there is a belt of lime- 
stone having a general northeast-southwest strike, which widens 
out toward its northern end. About 1828 a specimen of sapphire 
corundum was found at Franklin Furnace in a detached piece of 
rock composed essentially of feldspar, and although search was made 
no more specimens were found in this vicinity. A few years later 
sapphire corundum was found in Newton Township, about G miles 
from Franklin Furnace, embedded in a feldspar and partly surrounded 
by a carbonate. This occurs near the contact of the limestone with 
the granitic rocks of this section, and it is very evidently the result 
of contact metamorphism. Dana reports the occurrence of sapphire 
corundum in these limestones near Newton and Vernon, Sussex 
County, N. J., and near Amity, Orange County, and Crugers Station, 
Westchester County, N. Y. 
Prof. W. P. Blake 2 has described the occurrence of red sapphire 
corundum in the white crystalline limestones in Vernon Township, 
Sussex County, N. J. The finest specimens were ruby red in color 
and the others were of various shades of purple. The crystals were 
translucent, but no transparent ones were observed. They were 
embedded in the limestone and it is not improbable that crystals 
may occur in the similar rocks of the adjoining counties of New York. 
The New Jersey occurrences seem to be well authenticated, but 
those from New York are not. In the report of the New York State 
Museum for 1895 on the mineral resources of the State there is no 
mention of the occurrence of corundum at this locality, and in the 
report for L898 it is stated that no sapphire corundum is found in the 
State. 
CORUNDUM IN CYANITE. 
The occurrences of corundum associated with cyanite are quite 
widespread, and at times there are large masses of cyanite in which 
are numerous hexagonal crystals of corundum. At Litchfield, Conn., 3 
a mass of cyanite containing crystals of a dark, grayish-blue corundum, 
which was said to have weighed 1,500 pounds, was found. Large 
masses of cyanite have been found at various points in North Caro- 
lina in which there were well -developed crystals of corundum. 
All the occurrences that have been noted have been from surface 
specimens, and the rocks in the vicinity have always been either schists 
or gneisses. It is without doubt in connection with these rocks that 
the cyanite and corundum originated. I do not believe that the cyan- 
ite is usually an alteration product of the corundum, as has been sug- 
1 Am. Jour. Sci., 1st series, Vol. XXI, 1832, p. 319. 
2 Idem, 2d series, Vol. XIII, 1852. p. 116. 
3 Idem, 1st series, Vol. VI, 1823, p. 219. 
