1885. ] Mineralogy and Petrography. 1097 
pasoite (no. sp.) ; (7) proposite. Phenacite, zircon, topaz, cassiterite, 
uorite and several other species also occur in the granite of Pike's 
Peak, in addition to the common microcline and smoky quartz. 
Minor investigations on the luster of sanidine in certain rhyolites ; 
on the occurrence of topaz in nevadite; short notes on many ob- 
served minerals, including the two new species zunyite and guiter- 
manite, already mentioned in the Naturatist’s notes, make up 
the other chapters. 
Bulletin No. 12 of the U. S. Geological Survey contains a ve 
interesting study, by Professor E. S. Dana, of “thinolite,” a 
name applied by Mr. Clarence King to an enigmatical calcite 
pseudomorph which occurs abundantly in the old lake basins of 
the far West. This mineral was at first considered a pseudomorph 
after gaylussite ; Professor Dana, however, shows that this cannot 
be the case as the original form was clearly tetragonal. What the 
‘chemical composition of the original mineral was, it is impossible 
to state with certainty, but judging from the analogy of well-know n 
lead-carbonate pseudomorphs after phosgenite (PbCO; + PbCl,), 
the author thinks it quite probable that the original form may 
lave been a similar double salt with the composition CaCO; + 
NaC? or CaCO, 4 2NaCl. 
_ M.S. L. Penfield! has described crystals of the rare selenide of 
mercury, tiemanite, from Marysvale, in southern Utah. They 
are tetrahedral and closely resemble crystals of sphalerite. Ob- 
Served forms are Oœ (a); + (o0); — > (Or 5 555 (w) and 
TAT 
ea s3 (g) — other indistinct positive hemi-trisoctahedra appear 
on some crystals as striations. The crystals measure less than 
3™™ in diameter. They are of a black color with a high metallic 
luster. Twins parallel to the octahedral face are very common 
he same writer? also describes crystals of the allied black 
Sulphide of mercury, metacinnabarite, which has heretofore been 
generally regarded as amorphous. They come from the Red- 
dington mine, Lake Co., California, and measure as much as 4™™ 
in diameter. This mineral is in all respects isomorphous with 
i : o $ 202 209 
tlemanite. Observed forms are + -; + agit Por and ae (?), 
The intermediate compound, onofrite, Hg (S, Se), is not yet 
known in distinct crystals, but is doubtless isomorphous with the 
two minerals mentioned above. 
_ Mr. Penfield? has likewise described and figured some interest- 
ing analcite crystals from the Phcenix mine in the Lake Superior 
Copper region. They show the usual trisoctahedron, 202, with 
‘American Journal of Science, June 1885, p. 449. 
a P. 452. 
pe Aug., 1885, p. 112. 
