0. U. Shepard— Mineralogical Notices. 405 
This raised to 100 gives 
Calculation requires 
a8 38°08 49°30 + 142 = 0°347 
CaO 35°35 44:59 — 56 = 0°796 44°06 
H,O 4°84 61ll— 18 = 0°339 6°29 
79°27 100-00 100°00 
Admitting the foliowing formula: 
3(Ca,H,P,O,)+Ca,P,0,+H,0. 
The substance above analysed is undoubtedly identical with 
that from Monk’s Island (Caribbean Sea) described in 1856, in 
this Journal, vol. xxii, p. 97, and named Pie from its very 
striking property of decrepitation when ted.* Whether it 
forms a true mineral ie — aepent von more extended 
an uniform compound af bnanite and monite. It may, how- 
ever, prove only a mechanical mixture of the two. Whether 
chemical or certains it is re pee to admixture with 
gypsite, alumin and iro n phosphates, silica and organic 
ase i covstitating the Pri coe shaphato rock of the West 
Indies and Sout 
It Ay be ndded i in + coneliniod that the collection embraced 
several specimens of antillite, which is identical with the 
trappean rock mentioned in connection with the pyroclasite of 
Monk’s Is nd. 
* Ana ated mineral which | then ap ea and called glaubapatite is 
siladatilly the the « same thing; the soda found therein having without doubt been 
i aged state of t i 
Note on Crystals of dies The erystals of enna placed in ag hands 
may with tolerable certainty be referred to the triclinic e general 
form is that of a rather thin rhomboid The longer lateral oda is replaced by the 
plane 100 (a), Pe the shorter by the — 110 (J); there are se present in 
this zone the brachypinacoid 010 (), and two other hemi-prisms hko (m and n) 
te ‘ 
ment angles are: «J (100 _110)=42°, ab (100 . 010) = 81°, am=17°, an=28°, 
al=18°, ac==76°, ae (100 . 101)=1: 38°. “There appears to be a distinct cleavage 
el to a e crystals often interpenetrate each o) forming complex 
groups, but there is no uniform law of composition.-—-E. 8S. Dana 
Charleston, Feb. 18, 1982. 
