F.W. Clarke — Some Nickel Ores from Oregon. 483 



Aet. XLII. — Some Nickel Ores from Oregon • by F. W. 



Clarke. 



In or about the year 1881, extensive deposits of nickel sili- 

 cates were discovered in Douglas County, Oregon, In appear- 

 ance, the ores are identical with the so-called " garnierite " and 

 " nonmeaite " of New Caledonia, and many specimens bearing 

 those names have found their way into collections of minerals. 

 At present, the deposits at Riddle, Oregon, are being worked 

 by the Oregon Nickel Company, and through, the kindness of 

 Mr. Will Q. Brown, an admirable series of the ores was re- 

 cently sent to the United States Geological Survey for investi- 

 gation. According to Mr. Brown the deposits all lie at or 

 near the surface, in beds from four to thirty feet thick. Min- 

 ing is carried on through open cuts or quarries, and no second 

 bed has ever been found underlying the first. 



The specimens at my disposal represent a wide range of 

 appearances. They include samples of the country rock and 

 of the associated chromite, and the nickel silicates themselves 

 vary much in color and texture. The finest specimens are 

 bright ajjple green, and quite compact, and from this they 

 range through duller shades into masses of distinctly earthy 

 texture. Most of them are intermixed with oxides of iron 

 and with quartz, and even the purest mineral, like the garnier- 

 ite of New Caledonia, is seamed with thin sheets of chalced- 

 ony. All of the nickel bearing samples are much decom- 

 posed ; and one particularly beautiful specimen is distinctly a 

 conglomerate or breccia, having nodules of the green ore im- 

 bedded in it side by side with pebbles and fragments of other 

 material. Like all the nickel silicates which have been so far 

 observed in nature, these ores are unmistakably products of 

 alteration ; and the problem of their genesis is somewhat inter- 

 esting. For comparison with them I had a suite of the New 

 Caledonia minerals, received from Professor Liversidge, and a 

 large series of the genthites from Webster, N. C, collected 

 last summer by Mr. W. S. Yeates. All three localities have 

 much in common, and the three sets of specimens point clearly 

 to one conclusion, which will be stated farther on after the evi- 

 dence for it has been presented. 



In composition, the nickel silicates from any locality vary 

 widely ; for the earthy nature of the material renders it im- 

 possible to secure anything like a homogeneous substance for 

 analysis. The purest specimen of the Riddle ore was dark 

 apple green, compact, and amorphous ; but so permeated with 

 films of silica that a definite mineral could not be isolated. 

 With the best material obtainable I secured the following re- 



