522 



0 0 P P E 11 ORE ON THE BARRABOO R I V E R. 



tion of the rock, it lies exposed on the surface in loose, rough masses, usually small, 

 but occasionally six or ten inches in diameter. 



Amongst the loose rubbish thrown from one of the " prospect holes" where the 

 sandstone had been reached, I found numerous remains of Trilobites, like those 

 which occur in F. 1, d, immediately above the Coarse Lingula Grit, seven miles 

 above Richland, on the Wisconsin. 



The position of the copper-bearing " pockets" seems to be in members c and d of 

 F. 1. No regular veins have been discovered. Mr. Barry collected in all about 

 eight hundred pounds. 



About one mile beyond these copper discoveries the hills are two hundred feet 

 high. 



On Section 34, Township 12 north, Range 6 east, I found another quartzite range, 

 bearing nearly east and west. Some part of this formation, near its base, is regu- 

 larly stratified in layers from an inch to a foot in thickness, with a dip of about 

 15° to the southwest ; above these beds, however, the massive cliffs of flinty quartz- 

 ite exhibit no regular bedding. This range extends for more than a mile to within 

 a short distance of the Second Mill on the Barraboo. Here, as at the other locali- 

 ties where the quartzite exists, veins of milk-white quartz traverse the formation 

 without regularity as to bearing. The altitude of the range is one hundred and 

 ten feet above the Barraboo. 



Two miles and a half southeast of Adams, another quartzite range was traced by 

 Mr. Pratten, precisely similar to those heretofore described, having a bearing nearly 

 east and west, and an altitude of one hundred and fifty feet. Here the veins of 

 milk-white quartz had a more regular disposition, running nearly vertically with a 

 north-and-south bearing. 



Four miles east of Adams, the sandstone is but slightly altered, and has a height 

 of seventy-five feet ; though much broken, the layers are stratified. 



One mile beyond, in the same direction, ten feet of nearly white quartzite crops 

 out at the base of the hills, exposed in layers of about one inch in thickness, and 

 surmounted by thirty-five feet of sandstone ; this again is overlaid by one hundred 

 and fifty feet of reddish quartzite. From this point the quartzite ridge can be 

 traced, bearing to the east, across the Barraboo, with an elevation of about four 

 hundred feet above the river. 



In the valley of a small creek, a mile and three-quarters southwest of the Barra- 

 boo, the encrinital calcareous bed :!: of F. 1 is seen in a quarry where it has been 

 got out for the use of the limeburner. Its thickness is fifteen feet. 



* An analysis of a specimen from this bed yielded : 



Carbonate of lime, ...... 50-00 



Carbonate of magnesia, ..... 41-70 



Insoluble earthy matter, ..... 3-10 



Alumina, oxide of iron, etc., ..... 2-60 



Water, . . . . . . 1-00 



Loss, . . . . . 1-6 



100-00 



