214 FIELD COLUMBIAN MusEuM—GEOLOGY, VoL. II. 
ring in the form of “‘octahedrons, or of octahedrons modified by the 
cube and trapezohedron. The hematite is described as showing 
striations which indicate rhombohedrons. The phenacite is described 
as occurring in crystals, in part imbedded in a quartz porphyry 
and in part loosein clay. The crystals are said to be generally dull 
and whitish on the surface, but clear and wine-yellow in color within. 
An analysis of the phenacite is given, but some peculiarities of this, 
as pointed out by Cohen,* throw doubt not only on the analysis, 
but also on the report of the occurrence. The pycnite is stated to 
occur in stalk-like aggregations lacking determinate crystal form 
and yellowish brown in color. The fluorite is described as occurring 
in very beautiful crystals of green and blue colors, having generally 
the cubical form, at times modified by the tetrahexahedron and 
hexoctahedron. The garnet is described as occurring in small trans- 
parent crystals of rose color. No mention of the occurrence of martite 
or apatite 1s made by this writer. 
Martite from the mountain was described by Silliman. Dana 
mentions this martite, also phenacite,t apatite,§ topaz, magnetite, 
cassiterite, and durangite,|| references to authorities for the latter 
occurrences not being given. 
Rangel reports in addition to hematite—of which he notes solid, 
specular, micaceous, and ochreous varieties—martite, quartz, apatite, 
topaz, and a phosphate of iron occurring in the form of a yellowish 
powder. 4] 
The topaz, or pycnite (‘‘pricnita’’), is described by Rangel as be- 
ingin the form of small, symmetrical rhombic prisms, presenting various 
prismatic faces, and at one extremity combinations of pyramids and 
domes, while the other is terminated by the base. ‘The color of the 
crystals is described as hyaline white, rose, or pale yellow. 
The apatite is described as occurring in simple crystals, either 
alone or in company with oxide of iron; likewise as in veinlets or 
masses in which well-formed crystals of large size occur. The best 
crystals are said to occur at the point called “‘Cueva de los birilés”’ 
(Cave of the beryls?). Thecolor of the crystals is described as honey- 
yellow to greenish yellow, and their length as nine or ten centi- 
meters. . The crystals are said to present a multitude of prismatic 

LSA VSUVIOL 13 ht aes 
fAm. Ji, Sc. 24; 375, 183395 
tSystem of Mineralogy, 1893, p. 463. 
§System of Mineralogy, 1893; p. 767. 
System of Mineralogy, 1893, p. 495. 
(Op. cit., p. 6. 
