C. U, Shepard—Mineral Notices. 247 
termined by heating the mineral under lime. The mineral con- 
tains a trace of phosphoric acid. 
Al Fe Ca »@ Mg Na Fl Si HO _Insol. 
12-00 5:82 11:20 2°30 845 40°10 179 1044 1:08 
12°21 5°87 11°16 Seid es 40°51 eoes Seca scl Se gtk 
11:98 617 11:16 Seek anes hae sees ao oe eae 
Mean, 12-06 596 11:18 2°30 845 40°30 719 «10-44 =61-08 
HO = 10°44 19344 — 1:16 or 2 HO 
Al “== 19-06 4498 = °0886) y oog « of Al 
ae oe 598 = 0202 | — Fe 
Ca = 11:181}98 = 0559 “ 1 Ca 
Mg =. Soy aes se OT) - Mg 
Na = 845945 = etter ge 87 
Fl = 40°30 4239 = 2125 “ 4 Fl 
St. = eae o520 * 3 TS 
The deduction of a formula is difficult. The following is sug- 
gested : 
2(Ca-+2Na+4Mg)Fl+($Al4-}Fe)?SiFl2-+-2HO 
but it is very complicated; and it is uncertain whether Sif, is 
capable of counbining thus with metals. The iron was found to 
be present as sesquioxyd.” 
2. Cotunnite at South Hamptan Lead Mine. 
In a recent number of this Journal I have described scheelite 
as a rare product of the Hampton lead mine. [am now able 
to add cotunnite (PbCl) as a production, though similarly scarce, 
of the same locality. ‘Two or three specimens have been brought 
me by one of my pupils (Mr. P. W. Lyman, of the Junior _ 
class in Amherst College); and I have since heard of a fourth 
Specimen, found by another visitor of the mine. The crystals 
are small, and occur in groups lining druses of quartz, They 
have the form of ape eaee NA priems, are without transpa- 
rency and perfectly milk-white. When reduced to a fine pow- 
ler the mineral is soluble in water, from which the nitrate of | 
silver throws down the chlorid of silver. 
