156 FIELD CoLuMBIAN MusEuM—GEo Loecy, VoL. III. 
in Fig. 3; Pl. LIII. In calculating the forms the axial ratios estab- 
lished by Stevanovic have been employed rather than those of Mohs. 
These values are as follows: 
QD 3G. 4 =. 70,5002) ia 008 B= 000gsae 
The following is a list of the forms observed on the Mercur ae 
ment, those marked with an asterisk being new: 
a (100) @ (103) q (449) 
b (oto) *q (103) k (123) 
m (110) rie (O23 } *y (133) 
u (120) vp (343) t (243) 
OARS vu (ar) | 
Observed _—_ Calculated 
D A.0. oe (O16) aes = go° 28’ go° oo! 
aA I =e (TOO) a (110) — ae ee 30° 48/ 
aA ub.” = Goo) pat 25) = 80° 10! ioe ies Wi 
Gd. Ai O>, oe LOO ey menos = 41> 19° Wy ees 
Gi oA: +6 en TOO) a an Oa i TO ieee OOcmra 
e Ad = (ros) Ando ee 4o° 58 41° 32! 
DASE = O1O) Sey ano aay) a 65° aay COTras: 
OA LT OT eee oe = <4° ae siete! heh 
Vaan og) ene (343) A (343) = 61° a 1° e377 
DU Keg =: aflame oe = 82° 5B ees seas 
b Nm ‘= (010) Ay G33) = 59° 4503 5 Sonam 
OAR ie CTO Thee een ay Pes 7G a 72% a2" 
DN es OY KOLO) rales = 68° 413 Eye: 
OMAN RO b= (TOT) yet leas = 70, 100° 70° 48’ 
DA vs, el Ol ima ah) 75° 52 oa 
D°A 4 ~ =)\‘(or0) A 1243) = 54a 54° 43’ 
OWN 4 0) (TOL aN ray = 360°° 37) aes 
In connection with these crystals the well-known crystals * from 
this locality occurring in cavities in clay were examined. These 
crystals are of smaller size and are for the most part obviously twins 
but their planes were found to be so poorly developed that no satis- 
factory measurements could be obtained. 
-** App. Dana’s Mineralogy, 1890, p. 50. 
