[ellsworth-poiïevin] CAMSELLITE 7 



distinguishable by its characteristic cleavages, the latter by its low 

 birefringence. The fibres of camsellite are always flattened pareille! 

 to the axial plane. The extinction is parallel and suggests that the 

 mineral is orthorhombic. Its elongation is negative while that of 

 chrysotile is positive. The habit of the mineral does not allow the 

 emergence of an optic axis and for that reason jS could not be deter- 

 mined. No attempt was made to measure 2V, but this angle is 

 probably very large, a and y were determined by the oil immersion 

 method. 



Camsellite Chrysotile Serpentine 



Elongation Negative Elongation Positive 



a=1.575±0.005 /3=l.o44±0.003 



7=1.649±0.005 



Birefringence very strong 



(7-a) = 0.0"4' (7-a) = 0.013 



Pleochroism wxak. 



Paragenesis and Geological Relationships 



According to the description of Wm. McNeill of Merritt, B.C., 

 on whose claim the mineral occurs, it is located in an area of serpentine 

 14 mile wide by a mile long, about 30 miles east on a waggon road 

 Nicola station, which would bring it near the eastern end of Douglas 

 Lake in an area mapped by G. M. Dawson (Ann. Rep., G.S.C.. 1894, 

 vol. VU) as Lower Cache Creek formation of carboniferous age. Map 

 556 (B.C. Sheet No. 12, Kamloops Sheet) shows a mass of plutonic 

 rock, probably granite, about four miles in diameter occupying the 

 centre of this Cache Creek area, north of Douglas Lake, and probably 

 not more than a mile or two from the camsellite occurrence. Dawson 

 states that the rocks mapped as plutonic are chiefly granites and 

 syenites with some associated gabbro in places and are always in- 

 trusive, being chiefly of late Triassic age, while according to others 

 they are Jurassic. The Cache Creek formation, according to Dawson, 

 is made up. of limestone or marble as the upper members, with argil- 

 lites, cherty quartzites and contemporaneous volcanics in great 

 variety, as the lower part. Beds of nearly pure serpentine are associ- 

 ated with the volcanics. Dawson further states that "the rocks of 

 this formation are almost invariably shattered and dislocated in an 

 extreme degree." This fact is well evidenced in the camsellite, which 

 shows the effect of extreme shearing and crumpling actions which 



