Roeers.| . Minerals of the Galena-Joplin District. 481 
has the etch-pits as shown in figure 26. y. is characterized 
by curved striations. The other forms are subordinate, and 
may be dismissed without further remarks. Contact twins 
with S-,—3R as the twinning plane are frequent with this 
type of calcite. Following are the measurements made on 
crystals of this type: 
CrystaL. | Angle. measure Average. Calculated. 
No. 1. | p-am- | 1011,4041 3 30° 50’ 31° 29' 
No. 1. | p» aK: | 10114041 1 29 30 29 02 
No.1.] pan. | 1011,5051 2 33) 15 33 56 
No. 1. | F:aF:¥| 4151,5141 2 17 30 18 07 
No. 2. | e:ae:! | 4156/4516 1 55 00 54 07 
No. 2. | e:ae:¥ | 41565146 1 1137930 13 34 
No. 3. | e:ae:! | 415644516 2 54 55 54 OT 
- No. 4. | ean. | 0221p0445 1 25 00 94 40 
No. 5. | F:ajFz | 41534513 1 78 30 78 05 
No. 6. | e:ae:! | 41564516 2 54 55 54 OT 
Typr 8. 2-, —11R; ¢-, —2R; —¢R:S-—dh. 
Small amber crystals, averaging about 2 cm. in length, 
from Crystal Palace mine, west of Joplin. The three com- 
binations given above intergrade. They may be designated 
asa single type. The faces of %. have on them indistinct 
vertical striations, while those of ¢- are occupied by minute, 
slightly elevated, etch-hills of triangular shape, the apex of 
the triangle being directed toward the edge ¢g-/ 2: as shown 
in figure 44. Figures 42 and 43 illustrate the type. The 
following measurements were made ° 
No. of 
Angle. measure- Average. Calculated. 
ments. 
g-AX> | 0221,0-11-11-1 4 22° OT’ 21° 37’ 
aes OVAL a@st le Miell 8 22 22 21 37 
meats | 0445 ,0-11.11-1 3 46 10 46 27 
Se pars OULD AOS WIS Nsa 2 58 30 58 29 
