BCHALLER.] 
MINERALOGICAL BOTES. 
129 
Two terminated crystals of measurable size showed the following- 
forms: <?={00l}, 5={010}, «={100}, m={110}, t=$0l}, s={02l}, 
|=:{I31}. 
Measured. 
Calculated. 
*• 
p. 
</>• 
?■ 
c = 001 
o / 
90 25 
00 
90 14 
62 08 
90 03 
24 32 
18 18 
/ 
14 57 
90 00 
90 00 
90 00 
40 36 
32 50 
42 45 
/ 
90 00 
00 
90 00 
62 05 
90 00 
24 28 
18 03 
o / 
14 58 
1 =010 
90 00 
a = 100 
90 00 
90 00 
40 05 
i= 110 
t =201 
z = 021 
32 50 
1 = 131 
42 49 
Crystal No. 1 shows: a, b, c, m, t, z, i. 
Crystal No. 2 shows: a, b, — , m, — , z — . 
10. TRIDYMITE. 
Small hexagonal plates of tridymite, 1 mm. in diameter and rarely 
larger, are rather plentiful in places. The forms present on two 
crystals which were partially measured are <?={000l}, m={l0l6\, 
i={3250}, Z={5490}, r={3034{, /=}1012}. The first crystal measured 
was a twin. 
Measured. 
Calculated. 
Cyv C 

35 
90 
23 
26 
54 
43 
/ 
06 
02 
20 
39 
48 
54 
o / 
35 18 
c ^ m 
90 00 
m^l 
23 25 
iii^l 
26 20 
c,n r 
55 03 
c^f 
43 39 
11. ZINNWALDITE. 
The occurrence of this lithia mica has already been mentioned by 
Collier, a who has very kindly furnished the writer the numerous sam- 
ples collected. He gives as the exact localit} 7 : On Cassiterite Creek 
(extension or branch of Lost River), 5 miles from the coast and 8 miles 
i Collier, A. J., The tin deposits of the York region, Alaska: Bull. U. S. Ceol. Survey No. '229, p. 20. 
Bull. 262—05 9 
