A. A. Julien on Minerals of the Key of Sombrero. 377 
probable that in both B and C the material aay consists of 
zeugite, with bone sie cay of lime (as well as the 
of magnesia, etc.,) as mpurity, in proportions increasing 
until perhaps the seni bof 8CaO, 3PO, becomes too small to 
be distinguished. 
5. Ornithite—In the empty casts of Madrepores and other 
cavities of the coral limestone, in two Herre of the southern 
part of the Key, another new mineral o 
ystem monoclinic. Small crystals, whe over a fourth of an 
inch in length, usually very narrow, with the planes even and 
not polished, and —1-: very slightly convex, resembling some- 
h common form of gypsum. Clinodiagonal cleavage 
sb perfect; so that this, unlike the other minerals, is easi ly sec- 
. tile into very thin scales ; two other planes, as in gypsu 
: The broader crystals are arranged in radiating groups, while 
most of the narrower are isolated and strewn irregularly over 
the surfaces of the Seales No massive specimens of the min- 
eral have yet been fou 
Hardness =2°5; ( jut ‘scratches mica when rubbed upon - 
Lustre pearly on clino- ri greed Color white. Streak 
powder white. ‘Trans luce lexible. 
_When heated before the ipa pie in a closed tube, it darkens 
with sulphuric acid, the ereenish tinge of phosphoric acid is im- 
parted to the flame. ith 
solves readily, and apparently with greater effervescence than in 
es white and opaque by flaming: with a still ere 
excess, the bead is transparent and yellowish while hot, and 
Readily soluble in_nitrie 
Sesion under the jaro microscope. 
“The amount of this mineral in my possession being very small, 
only about one-tenth of a gram of pure crystals could be be used 
for analysis, and it was first ey dried at 100°C., with but 
7 Onaccount of the small size of the fragments _ their a the 
Wisiecios Cama flame, I was unable to datermine the effect of a long continued ignition; 
but at the end of a minute's ignition no trace of pet nape ey in 4 | 
