ROGERS. | Minerals of the Galena-Joplin District. . 483 
WYP WA, (Oopaplae 8 ti gapaeles’s Ion JR) S: (Gap —MR)) 8 (Gog ——eales) 6 
(m-,+4h) ; (b, oh) ° 
Small, colorless crystals from the mines of the Spring River 
Mining Company, west of Galena, and small to medium-sized 
ones from the Big Six mine, Chitwood hollow, are referred 
to this type, though the subordinate forms are not exactly the 
same on the crystals of the two localities. All the faces are 
bright except those of K-—R. : is striated in the direction 
of its acute polar edges. Figure 49 represents a crystal of 
this type. The following measurements were made: 
CRYSTAL. Angle. ee eee Average. Calculated. 
ments. 
No. 0. | t:atz | 21384,2314 5 41° 55’ 41° 55’ 
Wo; ©, | tient | BIBL ASIA 5 HO) 20 36 
No. 0. | t:,S- | 2134,0112 4 1 al 20 574 
No. 1. ‘t:atz | 2184,23814 1 42 ~«0 ANE) e) 
We. 1, | make | LOMMA~ALITT 4 90 52 90 48 
Now tt Sanke Onl Aol: 2 16 30 18 21 
Type 13. 9.,—2R; --,—5R; 8-,—3R; (D-,—4R) ; (O,OR). 
Medium-sized crystals of light amber color, with the first 
three mentioned forms (in a few cases S8- is lacking), occur at 
the Homestake mine, Granby, and at the Pelican mine, Jop- 
lin. Small, colorless crystals with the forms --, O, and D. 
are quite common at the Aurora mines. The faces of these 
crystals are rounded, and the combination edge ¢- A -: is not 
well defined. Figure 50 illustrates crystals of this type. 
Some of the measurements made on these crystals are as 
follows: 
Crystat. | Angle. measure Average. Calculated. 
INO, I, || @ Ase |) OBB pOSsI 5 15° 18’ 15° 25! 
Wa, @ | Ds poe lh OI MOA 3 93 45 23 56 
No. 3. |} s-ag- | 0112,0221 1 38 30 36 52 
No. 4. | ¢-a-- | 0221,0551 3 16 10 15 25 
No. 5. | ¢@ ja | 0221 ,0551 2 15 538 15 25 
