W. P. Headden — Golumbite and Tantalite. 99 



Etta Mine, but I have not been fortunate enough to find any 

 tantalite at this locality, and Professor Schaeffer's analysis does 

 not justify his identification. Professor Schaeffer states that he 

 was unable to find the least trace of columbic acid, and conse- 

 quently only the tantalic acid appears in the analysis. If we 

 calculate the atomic equivalents on this basis we obtain the 

 following values : 



Ta 35-60, Sn 0-26 = 35-86 and Fe 11-57, Mn l7*09 = 28-66 



The ratio is then 35*86 : 28 -66 = 1J : 1 instead of 2:1. If we 

 calculate the oxygen ratio on the same basis we obtain 31:1 

 instead of 5 : 1 ; whereas, if we consider that the 79-01 per cent 

 is all columbic acid and calculate the atomic ratios, we obtain 

 for Cb : Fe+Mn, 2 # 06 : 1 and the oxygen ratio becomes 5-1:1; 

 which are very close approximations to the true ratios for 

 columbite. A comparison of Professor Schaeffer's analysis 

 with analyses Xlla and b makes it evident that his specimen 

 was essentially the same mineral. 



The assumption that there is no tantalic acid in an Etta 

 columbite is contrary to the results of my tests and analyses, 

 still, it is only on this assumption that the analysis gives a cor- 

 rect ratio showing the mineral to be a columbite, but a very 

 exceptional one for the locality. 



In the summer of 1886 or 1887, Mr. Frank Hebert of Grizzly 

 Bear Gulch brought some stream tin to the Dakota School of 

 Mines to have it smelted and the tin run into bars. The yield 

 was exceedingly unsatisfactory and a portion of it was not 

 smelted, but by accident or otherwise was mixed with some 

 stream tin from Bear Gulch, a locality in the Northern Hills. 

 A little over a year ago I examined some of this material and 

 was lead to believe that some of it was tantalite, and the preced- 

 ing facts not being fully known to me at the time I supposed the 

 tantalite to be from the northern section of the Hills. This 

 was not the case ; as I have since found more of it in stream 

 tin from Grizzly Bear Gulch but have found none in the stream 

 tin from Bear Gulch. The stream tin in which I found the 

 tantalite was also from Mr. Hebert's placer ground near the 

 Tin Queen Mine. The largest piece weighs 5 grams and has a 

 specific gravity of 8 -2. The mineral has not yet been found in 

 place but these fragments have unquestionably been derived 

 from the Tin Queen lode which lies immediately above the 

 placer ground — this placer is worked for gold. The tantalite 

 is perceptibly harder than the columbite and the streak and 

 powder are dark brown. The method of analysis was the same 

 as for columbite. 



4m. Jour. Sci. — Third Series, Vol. XLI, No. 242. — February, 1891. 



