i?. A. Daly — Secondary Origin of Certain Granites. 187 



occasionally interrupted by thin intercalations of argillaceous 

 material. The formation is generally composed of nearly pure 

 quartz with a little mica, but some bands are feldspathic to a 

 notable extent. The total thickness of the formation is at least 

 9900 feet in the vicinity of Port Hill ; its base was not directly 

 observed. 



Immediately overlying the Creston quartzite is the conform- 

 able Kitchener quartzite, composed of about 7400 feet of a 

 highly ferruginous indurated sandstone. This formation is, in 

 the field, distinguished from the Creston quartzite not only by 

 the rusty color of the outcrops but also by a relatively thinner 

 bedding and a greater proportion of micaceous cement, once 

 somewhat argillaceous. Individual beds of the Kitchener 

 quartzite are charged with detrital feldspar, but the formation 

 as a whole is essentially composed of cemented quartz grains. 



Dark-colored red, brown, and gray shales with thin inter- 

 calations of gray quartzite conformably overlie the Kitchener 

 quartzite. The series, totalling 3200 feet in thickness, has 

 been grouped under the name of the Moyie argillite. This 

 formation appears but twice in the section and then only in 

 comparatively small areas. 



This great group of formations, from end to end of the sec- 

 tion, has been mountain-built. A few open folds broken by 

 faults appear in the eastern half of the belt, but the deforma- 

 tion has generally been due to the tilting of monoclinal blocks 

 separated by strong normal faults and, more rarely, by thrusts. 

 The tilting ranges though all angles up to verticality, but the 

 average dip is less than forty-five degrees. In consequence of 

 the deformation and subsequent denudation the edges of some 

 20,000 feet of well-bedded ancient sediment are now exposed 

 for study. There have also come to light a number of thick 

 sills of gabbro intruded at various horizons into the Kitchener 

 quartzite and the upper part of the Creston quartzite. The 

 intrusion and crystallization of the gabbro is believed to have 

 taken place before the upturning of the sedimentaries. The 

 faulting and tilting has repeated the outcrops of certain of the 

 sills. One of the thickest of them has, along with the quartz- 

 ites, been warped into one of the rare synclinal folds. The 

 thickness of the sills varies from 100 feet to more than 2500 

 feet. 



The main mass of each sill was uniformly found to consist 

 of a hornblende gabbro with essential green (primary) horn- 

 blende and plagioclase (labradorite to anorthite, the latter in 

 the cores of occasionally zoned feldspars). Accessory quartz, 

 often in considerable amount, always accompanies the other 

 accessories, which are titanite, titaniferous magnetite, and apatite 

 with often a little biotite and sometimes a little orthoclase in 

 addition. Epidote and chlorite are the principal secondary 



