32 CALIFORNIA ACADEMY OF SCIENCES. 



y (3 P|^) and iv (7 P^) occur each with a single face on a small 

 mutilated fragment showing, in addition, faces of s, t, n, v, o, h, 

 d and x. y is a very small rhombic face, determined by the 

 zones v : n and s : o, and replacing the angle formed by these 

 four faces. It gave a very faint, but single, reflection. 



to (7 P^) occurs on the same crystal on the edge and in the 

 zone y : n. It is extremely minute, barely discernible with the 

 unaided eye, but easily observed with a low power under the 

 microscope. It gave reflections on the goniometer only when 

 the lens was thrown in front of the telescope. 



V ( — P oo ) was observed once as a very minute face on the 

 edge b : b in the zone of the hemidomes. It has nearly the same 

 inclination to the orthodiagonal section as the positive heini- 

 doma h (2 Poo). For V, this angle is 42" 1' 33"; for h, it is 

 41° 44' 54". 



W (3 P oc) occurs on a crystal of totally different habit from 

 those figured in the plates. The form is columnar parallel to 

 the vertical axis, the front pair of faces of the primitive prism s 

 being largely developed, while its rear faces are comparatively 

 small; the only other lateral faces are those of the clinopiuacoid, 

 which are extremely small. Of the terminal faces, W itself 

 greatly preponderates over all the others; h (2 P oo) and ® (3 P 3) 

 are moderately developed, while o (2 P 2), v (2 P), d (2 P 2), y 

 ( — P), c (Poc), and g (o P), are all very small on the edges 

 of (~), W, and It with the front pair of faces of s (oo P). 

 All of the negative hemipyramids and hemidomes, togeth- 

 er with a (2 Poo) and n (oo P oo) are absent. The crystal thus 

 assumes somewhat of a pointed wedge -shape, the point 

 lying over the front edge of s : s, and one of the faces of the 

 wedge consisting almost wholly of W (3 P oo). The face of W is 

 somewhat curved and delicately striated, the striae radiating 

 from the lower part of the face. All of the faces on the crystal 

 are affected more or less with striae, mainly parallel to the plane 

 of symmetry, or irregular markings. The crystal was broken 

 from a large geode in massive colemanite, the inner surface of 

 which is completely lined with crystals of the same habit, all 

 of which show similar imperfections. The disturbance in the 



