298 



IRVING. 



Union, the Big Bonanza, the Little Bonanza, the Baltimore, the 

 Ross-Hannibal, and the Fanny. There are also many others. 

 Of these the writer has examined the Union and the Bie Bo- 



o 



nanza, and in addition many abandoned workings. 



The Union Mine. — The Union Mine is situated in Whitetail 

 Gulch, just west of Sugar Loaf Hill. The shaft has been sunk 

 through the base of the Sugar Loaf laccolite into the shales and 



Fig. 15. Diagrammatic section of the Union Mine in Whitetail Gulch. The 

 section is supposed to be in a north and south direction. The shaft was sunk some 

 distance east of the ore shoot but the ore has been shown in the diagram at the foot 

 of the shaft to illustrate its occurrence immediately above the basal Cambrian 

 quartzite. 



sandstones of the Cambrian, as far as the top of the conglom- 

 eratic quartzite, which immediately overlies the Algonkian. 

 See Fig. 15. Upon this quartzite the ore occurs as " Shoots " 

 or long flat channel like masses, >vhich have in general a north 

 and south direction. \\\ thickness the shoots vary from a thin 



