20 
THE PORCUPINE PLACER DISTRICT, ALASKA. [bull. 236. 
ASSAYS OF SAMPLES. 
Hardly enough material was taken to assure reliable commercial 
tests, but the presence of gold in all the samples indicates the advis- 
ability of careful prospecting for lode deposits. The following list 
gives the assay values of several samples from quartz ledges, min- 
eralized slates, etc., in the vicinity of Porcupine: 
Assay of mineralized quartz, slate, etc., from Porcupine district. 
No. 
Gold. 
Silver. 
Value. 
Oz. per ton. 
Oz. per ton. 
Per ton. 
1 
0.12 
0.08 
$2.48 
2 
.02 
Trace. 
.41 
3 
.26 
Trace. 
5.37 
4 
.06 
.08 
1.28 
5 
.02 
None. 
.41 
6 
1.10 
.08 
22.78 
7 
266. 60 
68.32 
5, 544. 20 
Locality. 
Mineralized slate, Porcupine Creek. 
Mineralized slate 1 mile north of Pleasant Camp. 
Large quartz ledge on ridge back of Porcupine. 
Large quartz ledge on north bank of Klehini 
River. 
Prospect 2 miles east of Porcupine. 
Glacial mud, Cranston claim; sample take 
at random. 
Black sand concentrate, 
Nugget Creek. 
from sluice box* 
Though a large amount of black sand has been thrown away in the 
past, its value is now generally recognized. The test given merely 
emphasizes the wastefulness of the rough methods of mining which 
have been employed. The sample marked "glacial mud, Cranston 
claim," was taken from a layer of rock flour and small pebbles, several 
feet thick, occurring between two beds of gravel. Too much impor- 
tance, however, must not be placed upon the high assay of this material, 
which was taken at haphazard, but it suggests that careful tests of the 
so-called glacial muds should be made. 
SOURCE OF PLACER GOLD. 
I 
The gold from Porcupine basin is well worn and flattened, occurri 
in flakes or small nuggets, and is but rarely rough and irregular. Its 
assay values are reported to vary from $16.80 on McKinley Creek to 
$17.20 on the lower portion of Porcupine Creek. It is of a bright 
yellow color, though some of the finer gold on the lower claims has a i 
dull bronzy appearance. Nuggets of an ounce weight are not unusual, 
and one piece is reported weighing 8 ounces. 
It is generally believed by the discoverers and operators that the 
gold of Porcupine and Nugget creeks has been brought from some dis- 
tant source. The supposed necessity of this view is urged from the 
coarseness and worn condition of the nuggets, and from the absence of 
coarse gold and of more than small amounts of free metal in any of the 
local veins. The importance of these facts can not be overlooked in 
