242 DEPARTMENT OF T\HE INTERIOR 



2 GEORGE V., A. 1912 



1. Type specimen of Creston quartzite. Analyst: Prof. Dittrich. 



2. Type specimen of Kitchener quartzite. Analyst: Mr. Connor. 



3. Specimen of Kitchener quartzite from contact zone, Moyie sill C. 



Analyst: Prof. Dittrich. 



4. Average of analyses 1 and 2. 



5. Average of two analyses of biotite granite in the Moyie sills. 



Mr. Connor has analyzed a specimen collected as a type of the Kitchener 

 quartzite itself. It was taken from a point about 400 feet measured perpen- 

 dicularly from the upper contact of the Moyie sill C, and this specimen repre- 

 sents what appears to be the average quartzite above, below, and between the 

 sills. It is .rather thin-bedded, the thin individual strata being grouped in 

 strong, thick plates sometimes rivalling in massiveness the beds of the Creston 

 quartzite. 



The thin section discloses a fine-grained interlocking aggregate of quartz 

 grains cemented with abundant grains of feldspar and mica. The feldspar 

 is so far altered to kaolin and other secondary products that it is most difficult 

 of accurate determination. Only one or two small grains exhibit poly synthetic 

 twinning and the preliminary study referred practically all the feldspar to the 

 potash group. Mr. Connor's analysis shows conclusively, however, that soda 

 feldspar is really dominant. The analysis was most carefully performed, the 

 second complete determination of the alkalies agreeing very closely with the 

 first. Supplementary optical study of the rock has pointed to the probability 

 that pure albite, as well as highly sodiferous orthoclase, is present. Quartz 

 makes up, by weight, 50 to 60 per cent of the rock, and feldspar from 25 to 

 40 per cent. Biotite both fresh and chloritized is the chief mica; sericite is 

 here quite rare. Colourless epidote is the principal accessory; tifanite, magne- 

 tite, apatite, a few zircons and pyrite crystals are the remaining constituents. 



The analysis is given in Table XIV, Col. 2. Column 4 of the same table 

 shows the average of Cols. 1 and 2 and may be taken as nearly representing the 

 average chemical composition of the quartzite invaded by the Moyie sills. 

 This average is to be compared with that of the two analyses of the biotite 

 granite of the sills, represented in Col. 5. The general similarity of the two 

 averages is manifest. There is clear chemical proof that the greater propor- 

 tion of the elements in the granite could have been derived directly by fusion 

 of the quartzite. 



The conviction as to such a secondary origin for the granite has been 

 enforced by an examination of the exomorphic contact-zone at the upper limit 

 of sill C For the perpendicular distance of at least 60 feet fiom the upper 

 surface of contact, the quartzite has been intensely metamorphosed. The rock 

 is here vitreous, lightened in colaur-tint, and exceedingly hard. Under the 

 microscope the clastic structure is seen to have totally disappeared. Reerys- 

 tallization is the rule. It takes the form of poikilitic or micrographic inter- 

 growth of quartz with various feldspars, along with the development of abtmd- 

 ant well crystallized biotite and (less) muscovite. The feldspar is chiefly micro- 

 perthite and orthoclase, the latter often, perhaps always, sodiferous. Albite in 



