Appendix C. 

 REPORT ON AURIFEROUS SANDS FROM YAKUTAT BAY. 



BY J. STANLEY-BROWN. 



Among the specimens obtained by Mr. I. C. Russell during the course of 

 his explorations on and about Mount St. Elias is a bottle of sand procured 

 from the beach on the extreme southern end of Khantaak island, Yakutat 

 bay, and characteristic of the shore material over a large area. This sand 

 was turned over to me for examination, and additional interest was given 

 to its study by the fact that it is from a comparatively uninvestigated 

 region and jjossesses, perhaps, economic value ; for the sample is gold-bear- 

 ing, and it is said that a " color " can readily be obtained by " panning " 

 at many points on the bay shore. ' 



Macroscopically, the sand has the appearance of ordinary finely commi- 

 nuted beach material ; but it differs in the uniformity of the size of its 

 particles from beach sand from Fort Monroe and Sullivan island, South 

 Carolina, with which it was compared. Its mineralogic constituents 

 greatly surpass in variety those of the sands referred to, but are markedly 

 similar to those of gold-bearing sand from New Zealand. At least twelve 

 minerals are present, with an unusual predominance of one, as will be 

 noted later. Through the mixture of white, green, and black grains, a dull 

 greenish-black color is given to the mass. The roundness of fragments is 

 such as usually results from water action, bvit it is less than that which re- 

 sults from transportation by wind. 



When put into a heavy liquid (Thoulet solution of a density of 3.1) in 

 order to determine the specific gravity of the constituents, it was found 

 that the sand is made up largely of the heavier materials, for the amount 

 that floated was trifling compared with that which quickly sank. Even 

 the abundant quartz was largely carried down by the weightier ingredi- 

 ents bound up within it, and only a few water-clear fragments were left 

 behind. This would seem to suggest that the lighter minerals are lacking 

 in the -neighboring rocks, or else have been carried to greater distances by 

 the sorting power of the water. 



Among the minerals recognized, gold is the most important, though rela- 

 tively not abundant. It occurs in flakes or flattened grains fi'om a quarter 

 to a half of a millimeter in size. The particles are sufficiently numerous 

 to be readily selected from their associates by the aid of " panning " and 

 a hand lens of good magnifying power, and if distributed throughout the 

 beach as plentifully as in the sample would, under favorable conditions, 

 pay for working. The flakes in their rounded character show the effect 

 of the agency which separated them from their matrix ; a separation so 

 complete that no rock is found adhering to the grains. 



(196) 



