164 DEPARTMENT OF TEE INTERIOR 



2 GEORGE V., A. 1912 



The great homogeneity of the three huge formations in the Purcell range 

 has rendered it as yet impossible to correlate in detail the 20,000 feet of strata 

 there exposed with the well-marked members of either the Galton or Lewis series. 

 As already noted, the fortunate exposure of the Purcell Lava conformably 

 overlying the Kitchener quartzite in its typical, eastern phase, affords an invalu- 

 able datum-plane. 



The Moyie argillite-sandstone formation is regarded as the equivalent of 

 the whole Gateway-Phillips-Boosville group as well as of the Sheppard-Kintla 

 group, though it is probable that the Moyie formation is stratigraphically a 

 larger unit than the Sheppard and Kintla combined. 



Apart from the occurrence of lenses or tongues of molar-tooth limestone in 

 the upper Kitchener, there is no indisputable field evidence as to the exact 

 relation of the Kitchener to the variegated rocks of the two eastern series. 

 A probable but tentative correlation may be based on the fact that the Kitchener 

 quartzite is typically ferruginous. The strata of the Galton series are domin- 

 antly ferruginous down to the base of the upper MacDonald; the strata of the 

 Lewis series are dominantly ferruginous down to the base of the Grinnell. 

 As illustrated by Table I. and Plate 20, the base of the Kitchener is accordingly 

 correlated with these two horizons, while the top is definitely fixed at the 

 Purcell Lava. 



The Creston quartzite was, in the field, differentiated from the Kitchener 

 quartzite by the non-ferruginous character and lower stratigraphic position 

 of the older formation. The gray quartzites and argillites of the Appekunny 

 and MacDonald correspond, even in details of colour, composition, ripple- 

 markings, etc., to the top beds of the Creston quartzite. The reddish beds of the 

 Hefty and lowermost Appekunny are not paralleled, so far as known, by reddish 

 beds in the Creston, but may be equated with the somewhat rusty-brown, strata 

 which occasionally occur in the Creston at horizons 1,500 feet or more below 

 its summit. Similarly, there is no evident lithological equivalent of the Altyn 

 anywhere within the Creston as exposed in the Boundary belt. 



The perfect conformity within each of the three great series is, however, 

 a strong argument for considering even the strongly contrasting Altyn dolomite 

 and Creston quartzite as stratigraphic equivalents. The massive Waterton 

 dolomite is similar in field-habit to certain parts of the eastern phase of the 

 Creston in the Purcell range. The vigorous upturning of the fault-blocks 

 in that range has occasioned the exposure of a specially great thickness of 

 beds filling the ancient geosynclinal; the lower one-half of the Creston forma- 

 tion as exposed in the Boundary belt seems to be older than 'the oldest beds 

 exposed in the Galton, Clarke, or .Lewis ranges in the same belt. 



The lithological contrasts between the different members of the Summit 

 series when compared with the members of the Purcell series, is almost as 

 great as the contrasts existing between the Lewis and Purcell formations. 

 Moreover, in the correlation of the western series we have no datum-plane 

 of absolute contemporaneity such as the Purcell Lava affords in the eastern 

 part of the wide geosynclinal. 



