386 Correspondence. 
characteristic of the Animike iron-bearing rocks of the Mesabi range. 
That there is sideritic iron in the Vermilion range we do not question. 
It is found in breccias and veins, but it is of secondary oi'igin and not 
a primary constituent. It is found in large crystals in company with 
vitreous quartz, pyrite and coarse micaceous hematite. 
N. H. WiNCHELL AND H. V. WiNCHELL. 
Minneapolis, Nov. 17, 1889. 
GiLSONiTE OR UiNTAiTE. This mineral was discovered by S. H. 
GiLsoN of Salt Lake and has ever since borne the local name of Gilson- 
ite. The first description, however, was published in a paper by Prof. 
W. P. Blake in the Engineering and Mining Journal of Dec. 26, lb85, 
under the name of Uintahite.^ He said : 
"It breaks witli a conchoidal fracture, is very brittle, and has a hard- 
ness of 2 to 2.5, wijth a sp. gravity of 1.065 to 1.07. It is black, bril- 
liant and lustrous, with a rich brown streak, fuses easily in the fiame 
of a candle, and has considerable plasticity when warm. It dissolves 
in the heavy oils and fats and in warm oil of turpentine. Ether dis- 
solves it in powder. It also dissolves in melted wax forming a com- 
pound resembling ozokerite. It is more fusible than Albertite and 
Grahamite, heavier than Piauzite and contains less oil and gas than 
Wolongonzite." 
The following analysis is reported in the same paper : 
Carbon 78. 43 
Hydrogen 10 20 
Nitrogen 2.27 
Oxygen 8 . 70 
Ash 40 
100.00 
With the added report on solubility — Bisulphide of carbon and chlo- 
roform dissolve it completely ; benzole dissolves 95 percent.; ether 
86.5 per cent, and absolute alcoliol 9.5 per cent." 
Spirit of turpentine, it is said, appears to be the best commercial 
solvent of this mineral. 
The Gilsonite or Uintaite occurs near Fort Duchesne and the line of 
the Uinta & Uncompahgre Indian reservations. It occurs in a vein 
about 5 feet thick, with smooth sides traversing sandstone. The vein 
has been followed for about two miles and traced downward about one 
hundred feet still retaining its full thickness. The upper twenty feet 
are somewhat comminuted by the weather, but not apparently altered 
in quality. 
It seems likely from other reports that there are other seams of the 
same or a very similar mineral in the neighborhood of the vein above 
described, and a company has been formed to work it in the hope that 
it will be suitable for the various purposes for which asphalt is now in 
■demand, especially for paving. Thus far it has been used for the man- 
