134 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



In fact it became strongly suspected toward the close of the season of 1904, 

 that a large part of the Kitchener quartzite is the strptigraphic equivalent, of 

 the Siyeh formation of the Rocky Mountains proper. This suspicion was raised 

 to a practical certainty when, in the following year, the sviccession and charac- 

 ters of the Galton series were marked out. So clear were the field evidences of 

 the equivalence that that part of the Kitchener formation which covers the 

 eastern twelve miles of the Boundary belt in the Purcell range could be 

 coloured in the map sheet as belonging to the more closely defined Siyeh 

 formation, rather than to the more extensive division, the Kitchener quartzite. 

 It was further deduced from a review of all the sections in the Purcell range, 

 that the top of the Kitchener formation coincides, in stratigraphic position, 

 almost precisely with the base of the Purcell lava formation. 



Since the eastern phase stands about midway, lithologically, between the 

 already described western phase and the Siyeh formation of the Galton range, 

 there is no special need of describing the eastern phase in detail. A thin 

 section of the molar-tooth limestone at the West Pork locality was specially 

 studied for purposes of 'comparison with the Siyeh limestone. The limestone 

 is here a light to medium gray or brownish gray, compact rock, weathering 

 buff and interrupted by the usual irregular partings, lenses, stringers, or round, 

 eye-like masses of much less magnesian, light-gray, compact limestone, weather- 

 ing gray or, rarely, pale buff-gray. 



The buff-weathering main part of the rock effervesces to some extent but 

 is clearly magnesian and silicious; the gray partings effervesce violently and 

 seem to be nearly pure calcite. The diameters of the carbonate grains in the 

 magnesian part vary from 0-02 to 0-1 mm. with an average of perhaps 0-06 or 

 0-07 mm. They enclose a notable amount of clastic quartz, orthoclase, micro- 

 perthite, and an indeterminable plagioclase, in grains averaging less than 0-1 

 mm. in diameter. The carbonate grains have the characteristic rhombohedral 

 development seen in the Siyeh and Altyn limestones and often show clean-cut 

 crystal outlines. 



The gray calcite partings are extremely uniform in character and lack 

 any significant admixture of silicious particles. The diameter of the calcite 

 grains steadily averages 0-03 mm; they are usually allotriomorphic. Here again 

 the evidence of the thin section corroborates the field evidence that the calcific 

 partings are segregations or secretions, formed after the limestone was well 

 buried. The systematic lamination of the specimen illustrated in Plate 10, B, is 

 clearly due to segregation of the calcium carbonate along shearing planes. In 

 the average case, the secretion seems to have accompanied a contraction of the 

 magnesian portion of the rock, possibly occasioned by the dehydration of the 

 original sediment. 



It should be noted, further, that the grain of this rock is very similar to 

 that found for the magnesian limestones of the Galton and Lewis series, an 

 important point to which attention will be directed in the section on the origin 

 of these limestones. 



The average specific gravity of thirteen specimens of the limestone (range, 



