University of California Publications. [Geology 



than the center. Sometimes the pigment forms, zones and patches 

 in the neighborhood of the clearer region, as if brought from 

 there through secondary influences. A fibrous crocidolite occurs 

 around and in some cavities of the katophorite in close connection 

 with the light zones. Between crocidolite and katophorite there 

 are always definite lines of demarcation, although the crocidolite 

 zone begins with a greenish yellow substance. For katophorite : 

 C:c — -31? The longitudinal and transverse sections show 

 many hemitropic lamellae on the (100). The optic orientation 

 as usual 6 = b\ axial plane parallel to (010). 2 V large, posi- 

 tive ; no appreciable dispersion. 



Fig. 9. — Katophorite, k, with halo of crocidolite, Cr. a = prismatic section ; 



b =basal section ; c = polysynthetic lamellae parallel to 

 (100); d. = pseudomorphs of rutile, r, after katophorite; 

 e = kataphorite with a circle of crocidolite ; f and g = 

 same with halo or sheaf of crocidoliet. X30. 



Some fragments are very dark colored, and we find some grains 

 of rutile surrounded by fibrous crocidolite ; clearly they are 

 pseudomorphs of katophorite. The pseudomorph is more distinct 

 in some prisms which show a periphery of rutile and a center 

 of katophorite with some fibers of crocidolite. (Fig. 9.) Very 

 probably we meet here with the phenomenon of separation of the 



