RED CREEK ARCH^AN BODY. 269 



tion most in accordance with the observed facts is, that a line of fault, 

 approximately such as is indicated on the map, has been developed by the 

 uplift of the Archaean body and the adjoining Weber Quartzite beds, which 

 has crossed the formations diagonally to their strike; that this has produced 

 a displacement, such as is indicated by the steep dips of the Red Creek 

 divide, and the want of correspondence in the dividing lines of the different 

 formations generally, to the north of the Archaean body. The continuation 

 of this line of faulting and displacement eastward, may be adduced as an 

 explanation of the peculiar position of the rock on the Owi-yu-kuts Plateau, 

 where, as will be described later, the flat dips along the main portion of the 

 plateau, in the beds of the Weber Quartzite, are suddenly changed along 

 the northern portion to steep angles of 50° and 60°. 



Red Creek AKCHiEAN Body. — The best opportunity for studying 

 the structure and character of this body is presented by Garnet Canon, a 

 narrow, precipitous, and winding gorge, which has been cut by Red Creek 

 to drain the basin-like valleys, which have been worn out of the softer Cre- 

 taceous and Tertiary beds to the north. A fair transverse section of the 

 body is thus exposed, which shows that its beds have been compressed into 

 sharp, narrow folds, and so contorted that their structure is somewhat com- 

 plex. The general plan of this structure seems to be that of a double anti- 

 clinal, whose axes converge and perhaps cross each other, one of which, 

 the northern, has a direction of northwest and southeast, and the other of 

 northeast and southwest. The dips observed in descending the canon are 

 first 70° north, which changes a short distance down to 70° south, forming 

 the first fold, which has a northwesterly strike, and runs in the direction of 

 the elevation north of Ashley Park. About the middle of the canon, this 

 dip changes again to 70° north, forming a sharp synclinal, and the north- 

 ern dip is continued to the mouth, decreasing, however, to 45°, while the 

 beds have a northeasterly strike, which would produce the southern side of 

 this fold along the foot-hills of Brown's Park to the east of the cai3on-mouth. 



The first rocks observed in descending from the Cretaceous valley 

 below the gap of Red Creek are white quartzites of remarkable purity and 

 great thickness. These pass, by gradations of quartzites containing a little 

 white mica, into white mica-schists. Included in these beds, in the axiss of 



