ALASKA-TREADWELL MINE 
61 
tween walls diminishes from about 400 feet at the pit level 
to about 350 feet at the 440-foot level, and the thickness 
of ore in the lower level is still further reduced by the 
presence of two bands of barren syenite, one 50, the other 
20 feet in width, and by a slate 6 horse ? about 45 feet wide. 
In other words, the ore body which at the pit level had a 
thickness of about 300 feet has diminished by one-third 
at the 440-foot level. It was expected by the superin¬ 
tendent that drifting along the deposit would show this to 
be only a local pinching of the ore-body, but whether this 
expectation has been confirmed I am not informed. 
The portion of the Treadwell deposit lying next south 
of the Treadwell mine and known as the ‘ 700’ claim was 
being exploited by an open cut in 1899, and ore was being 
taken out to a width of about 100 feet. 
No work was being done on the Alaska-Mexican mine, 
the next claim south, the mill being run on ore from the 
other mines. 
At the southernmost of the developed claims, the Ready 
Bullion, vigorous operations were being conducted, and 
had shown that here the regular Treadwell lode was much 
reduced in width, varying from thirty to not much over 
sixty feet; but in the foot-wall of the lode a well-defined 
quartz vein forty feet in width, dipping at a lower angle 
to the west and carrying much higher values, was dis¬ 
covered. Its relation to the main lode had not been 
thoroughly developed by deep exploitation; but it seemed 
to consist almost entirely of vein quartz, and thus to 
differ essentially in origin from the larger replacement 
deposits. 
Collections of ore and wall rock were made from all 
the parts of the mine visited, and their study confirms the 
results of Mr. Becker in all respects. The ore consists 
of a somewhat silicified sodium-syenite, which has been 
intruded as a large dike in the prevailing black slates of 
