Eakle.] 



Oolemanite from Southern California. 



39 



22. c, b, a, /, m, z, «, <*, h, U, P, y, v, «>. <1, x, o, ®, B, e. 



23. c, 6, r/, /, m, 2, K , a , \ i, °", //, ''. 0, </>. 



24. b, a, t, m. <*■, h, ifr, y, v, d. 



25. c, &, a, w*, K , a , //, </\ CT, //, y, d, 0. 



26. c, &, t, m, «, a, /, ft, r, /?, //. v, u >, r, d, e. 



27. c, a, ^, »?, K , A., i, //, P, y, v, (J, x, 0, £ , y. 



28. c, />, (/, /, K , u , h, *P, <r, ft, y, v, </, d, <>. 



29. C, 6, /, W, 2, k, <*, /8, //, y, 5, rf, £, Q. 



30.. c, &, >w, K , a , ?, h, //, v, q, d, <>. 



Projections. — Figures 1— 10, Plates 2 and 3, are clinographic 

 projections to show the habits and some of the combinations. 

 Figure 10 is a drawing of Crystal No. •">, which has the five new- 

 forms besides the two rare ones, e and y. The new form 

 (341) is a large face on this crystal. About two-thirds of the 

 crystal is broken, otherwise it would probably have shown a rich 

 combination of forms, as most of the common terminal forms 

 ai-e missing. 



Figure 11, Plate 3, shows an orthographic projection on the 

 base of all the forms, with their relative predominance. 



Plate 4 exhibits a gnomonic projection of the forms. The 

 pole of the projection, represented by the dark circle, is almost 

 midway between the projection of the base (001) and the dome 

 (101), and since e' is almost -y-, the angles <t> and p for the faces 

 on the positive side of the pole vary only a few minutes from 

 those at corresponding distances from the pole on its negative 

 side. The crystals of colemanite therefore have an apparent 

 orthorhombic symmetry, and the definite orientation of some of 

 the crystals had to be determined by the direction of extinction 

 on the clinopinacoidal section, this direction making an angle 

 of about 6° with the vertical axis, in the acute angle @. 



The projection shows the excellent series of zones in which 

 the forms lie. Most of the prominent zonal intersections on the 

 negative side of the pole are occupied by faces, while on the 

 positive side, several of these prominent intersections are not 

 represented by forms, as, for instance, the cross zone 2p n has 

 only the one form (201) in it. Two of the negative pyramids, 

 p(.123) and w>(182) have their projections on the positive side of 



