REPORT OF THE CHIEF ASTRONOMER 



409 



SESSIONAL PAPER No. 25a 



Analysis of chilled contact-phase, Hock Greek chonolith. 



Si0 2 .. 

 TiO.. 

 ALO\. 

 Fe.0,. 

 Feb.'. 

 MnO. 

 MgO. 

 CaO.. 



SrO 



BaO 



Na.0 



K„0 



H„0 at 110°C. ., 

 H 2 above 110°C. 



P 2 s .. 



CO, 



Mol. 



5243 



874 



•86 



Oil 



19-18 



188 



3-51 



022 



2-08 



029 



tr. 





2-61 



065 



3-71 



066 



42 



004 



•35 



002 



4-85 



078 



5-95 



064 



•27 





349 



-178 



42 



■003 



tr. • 





99-83 





Sp.gr 2-608 



The oxides are present in proportions essentially similar to those in the 

 central phase. The almost perfect freshness of this rock shows even more clearly 

 that the water, great in amount as it is, is an original constituent and is 

 derived chiefly from the base of the rock, a small part of it emanating from the 

 mica. 



The norm of the chilled phase of the chonolith has been calculated as 

 follows : — 



Orthoclase. . 



Albite 



Anorthite.. . 

 Nephelite. . . 

 Hypersthene . 

 Diopside.. .. 

 Magnetite.. . 

 Ilmenite.. .. 

 Hematite. . . 

 Apatite.. .. 

 Water 



35-58 



20-96 



12-79 



10-79 



4-90 



346 



4-18 



1-67 



-64 



-93 



. 346 



99-36 



The rock is borolanose in the Norm classification; a basic rhomb-porphyry 

 in the older classification. 



Other Intrusions of Rhomb-porphyry. 



A smaller intrusive mass of the porphyry occurs on the slope south of the 

 Kettle river about two miles below Rock Creek post office. The exposures are 

 not extensive but the body is elongated and seems to have a dike-like form, at 

 least 1-5 miles long by 400 to 800 yards in width. It cuts the Paleozoic phyllites 

 and quartzites as well as a small patch of Tertiary sandstone at the southern end 

 of the body. The northern end cannot be seen, as it is covered by the Kettle 

 river gravels. On account of the imperfect exposure, the exact structural rela- 



