336 University of California Publications in Geology [Vol. 10 



calcite. This friable granular variety has every appearance of having 

 been thrown down as crystalline precipitated granules from a cooled 

 saturated solution of the lime silicate. The precipitate was crystalline 

 as every grain is transparent glassy, but the imperfectly formed 

 crystals were not cemented into a compact mass which would have 

 been ordinarily the case in a dense crystallization such as this implies. 

 Presumably this mass, which seems to be a large segregation in the 

 limestone, was formed by rapid crystallization and sudden precipita- 

 tion from a solution whose temperature was rapidly lowered. This 

 variety is only found on the northern end of the hill and at some 

 distance from the intrusive dikes. 



The fourth type consists of distinct crystals which have formed 

 by later silica solutions acting upon the limestone in the vicinity of the 

 pegmatite dikes and on the outer border of the contact zones. Acicular 

 and slender crystals with terminations on one end occur associated 

 with apophyllite and okenite. The crystals are clear and colorless, 

 with bright lustrous faces. By pressure they separate into silky fibers. 

 They possess perfect orthopinacoidal cleavage and have the usual 

 elongation parallel to the ?>-axis. Twenty-three forms were observed, 

 of which twelve were new, as follows : 



c (001) v (101) g (Oil) u (T44) new 



a (100) r (104) new p (744) new <p (122) 



I (740) new 6 (T04) new o (344) new ^ (T22) 



h (540) (T03) n (144) new u, (142) new 



q (340) a (T02) b (744) new e (T42) new 



m (140) new t (T01) i (344) new 



The crystals are slender and consequently the dome faces are nar- 

 row and apt to be striated. The base, orthopinacoid and three domes 

 vat are common to all the crystals. One crystal gave readings for 

 narrow but distinct forms corresponding to two new domes (104) and 

 (T04) . The end terminations of the crystals are remarkable. The unit 

 prism (110) and elinoprism (120), which are common forms on wol- 

 lastonite, are absent, and a new prism (140) predominates; the prisms 

 (540) and (340), known forms but very rare, are common on these 

 crystals. The pyramidal forms are likewise remarkable in showing a 

 similar odd series of symbols and no forms common to the usual 

 crystals of wollastonite. Practically all of the pyramids are new 

 forms. The forms (144) and (144) are common on all, with (344) 

 and (344) usually present. Two of the crystals have small faces of 

 the forms (744) and (744). The forms (544) and (544), which 



