304 Hillebrand and Washington — Minerals from Utah. 



r (101, -1-i), t (ill, 1) and^> (ll3, -§•), the other planes observed, 

 were all dull or rounded, and only capable of giving angles 

 accurate enough to identify the forms. Of the planes above, 

 t and p are new to the species. Most of the crystals were 

 apparently made up of two or more individuals in nearly par- 

 allel position but inclined slightly in the zone c/b. A measure- 

 ment in one case gave the angle 4° 10', but as it is not the 

 result of twinning, this angle of course is not constant and only 

 shows the very slight inclination of the individual crystals. A 

 consequence of this method of growth will be described later. 



The crystals were all simple ; fig. 3, or a combination of that 

 with r, being the most usual. Occasionally the lower half of m 



is replaced by t, as shown in fig. 5, giving the angle 13° 20' 

 (calculated 13° 17') for in^t. The new plane <p (il3) was ob- 

 served in several crystals and is shown in fig. 4. The follow- 

 ing angles were obtained for it : 



c*p, 001 / 

 s*p, 302, 

 p ~p', 113 



Observed. 

 113 = 61° 6' 

 11;! = 50° 14' 

 ^113 = 82°" 



Calculated. 

 61° 26' 30" 

 51° 19' 10" 



85° 48' 



The angles are merely approximate, but sufficient to establish 

 the form. The crystals are for the most part elongated in the 

 direction of the b axis, with a length of from 2 to 3 mm , and 

 show easy cleavage parallel to c. 



The other type of clinoclasite is interesting, as showing the 

 consequence of the nearly parallel growth of the crystals men- 

 tioned above. In some of the specimens the crystals are 

 grouped about the b axis, with c exposed. They are inclined a 

 trifle in the zone c/b an'd also in the zone a/b, thus rounding off 

 the group in two directions, but decidedly more in the latter 

 zone, forming, with the elongation in the direction of b, dis- 

 tinctly barrel shaped forms. Occasionally the curvature in the 

 zone c/b is carried still further, producing globular forms. In 

 all cases c forms the outer surface and the crystals are closely 

 crowded together, producing a bright and coarsely rough sur- 

 face. 



The material analyzed consisted of the globular masses men- 

 tioned above, and was probably not as pure as the crystals and 

 barrel-shaped forms. A trifling amount of insoluble matter 

 (0*05 per cent) has been deducted. For comparison Mr. 

 Pearce's partial analyses are also quoted. 



