THE TRAP MINERALS OF NOVA SCOTIA—GILPIN. 291 
The following analysis is by Dr. How, of a specimen from 
Port George : 
Si 0. — Al 0. — Ca 0. — HO. 
57°43 — 21-64 — 1207 — 15-26. 
Gyrolite. Found on apophyllite between Margaretville and 
Port George. The following is an analysis of it : 
Si. 0. — Al 0. — Me. 0. — Ca. Oi KO — HO 
51:90 — 127 — 08 — 29:95 — 160 — 15-05 
Centrallasite. This mineral, regarded as a variety of Okenite, 
occurs with Cyanolite and Gertie in amygdaloid. It is of a 
radiated and lamellar form and of a whitish colour with pearly 
lustre. 
The following is the composition of a Nova Scotia specimen : 
si. 0. — Al 0 — Me. 0 — Ca.0— KO — HO 
2 2 3 2 2 
186 — 114 — 16 — 27:92 — +59 — 11°42 
Cyanolite. Amorphous of a bluish gray colour, and little lustre 
—oecurs at Black Rock and vicinity. The following analyses 
are by Dr. How : 
SiO — Al 0 — Ca 0.— KO ea) 
z 
7415 —_ 34 BaP EOt Ae Nite Sih Se NBO 
Ae ATS 39) So 6k Sete i 
Dana remarks that it is probably the same as Centrallasite 
but impure with silica, or it is the same mineral with Chalcedony. 
Lowisite. This, the latest addition to our list of trap mine- 
rals, may be inserted here. Its colour is leek green, translucent 
with vitreous lustre. 
The following analysis is by Mr. H. Louis : 
Si 0O—Al 0—Fe 0—Ca 0—Mg 0—K 0— Na 0—H 0 
6374— -57— 125—1727— 38 3:38-3:38 0812-96 
It is apparently intermediate between the two last named 
minerals, and may perhaps be considered a variety of Okenite. 
Chrysocolla. A silicate of copper holding water and iron is 
occasionally found as an incrustation. 
The Unisilicutes are represented by the Calamine and Apo- 
phillite groups. 
