276 The Stillwater Deep Well— Meeds, 



25. This rock consists of material same as last but 



mixed with a large amount of calcite and pinkish 

 grains of feldspar, giving it a^ mottled light ap- 

 pearance. At a depth of 2,450 ft. another salt 

 pocket was struck and a small amount of brine 

 continued to flow into the well to the close. A 

 thin section of a piece of the light material proved 

 to be a hornblende biotite granite in which the 

 feldspar is quite badly altered to kaolin 650 ft. 2900 ft. 



26. Darker than last; less of the light colored material. 



In this was found a piece of quite a large pebble, 



one surface worn smooth and rounded 46 ft. 2946 ft. 



27. Dark red sandstone about same as 21. In thin sec- 



tion it appears to be almost identical in general 

 characters with that occurring at 2,200 feet. It is 

 badly altered and the more intimate structure of 

 the grains is difficult to make out 4 ft. 2950 ft. 



28. A very dark-brown diabasic rock with pieces of 



kaolinized feldspar and some green grains 235 ft. 3175 ft. 



29. Consists of the dark brown diabase similar to last, 



with some kaolin, calcite, and a notable amount of 

 a green mineral found in long slender fibres, half 

 an inch long, probably serpentine 100 ft. 3275 ft. 



30. Slate colored, fine grain diabase. In this rock 



pieces of native copper were found 25 ft. 3300 ft. 



31. Same as last but mixed with considerable white 



material as in 29 5 ft. 3305 ft. 



32. Same as 30 5 ft. 3310 ft. 



33. Same as last 91 ft. 3401 ft. 



34. A very fine grained drab colored rock which is 



reduced to dust, it is so finely broken up. It is a 

 diabasic rock, with some white and some green ma- 

 terial 39 ft. 3440 ft. 



Slides were made of the rock at 3,275 ft., and at other depths 

 to the bottom. The rock appeared to be a diabase porphyrite, 

 which at places is very fresh, as at 3,300 ft., and at other depths 

 somewhat altered, as at 3,275. Where altered, it shows a darker 

 color, the formation of hematite, the kaolinization of feldspar 

 which is near labradorite, and the occurrence of quite numerous 

 cavities filled with calcite. It does not appear from thin sections 

 examined whether the calcite fills amygdaloidal cavities or cavi- 

 ties formed during the process of alteration which the rock has 

 undergone. The feldspars for the most part have the peculiar 

 lath-like shape noticed in layers above and the augite occupies in- 

 terstitial places. There is comparatively little opaque mineral in 



