The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1891-08-19

broad road of ore twenty-elght feet wide
and traceable up the mountain side till
lost beneath the perpetual SHOWS.
The ores taken from this and other
mines are very much alike in appearance
to the unscientific observer. They appear
to be masses of leaden-colored rock bright
at points of recent fracture, notable for
nothing more than their exceptional
weight. In general character they are
base ores bearing sulphurets of iron, and
galena ore showing some zinc. The per-
centage of lead is very large-much larger
than is required for smelling the precious
metals that they contain. Parallel with
nearly all the veins of galena ore there are
bodies of iron pyrites frequently mixed
with metamorphosed porphyry. In gen.
eral way, it may be said, that these ores
carry from to 80 dollars in gold,
from 10 to IS dollars in silver, and from
Il to 60 per cent. of lead. The greater
part Of the ores are of a sort which can be
worked by concentration processes, but
some of the heavier gold ores will require
roasting and perhaps treatment by the
chlorinatlon process
With the idea of atfording the scientific
reader something better than a report on
mere superficial observations, asked Mr..
r. HI. Stretch, mining engineer, whom /
found al Monte Cristo, for brief treatise
on the geology of the district, and he
kindly furnished me with the following,
which is the result of close and accurate
observations made by himself, while pur-
s;iing his work as an engineer and sur
veyor:
The rocks of the district are few in number,
consisting OF highly metamorphosed states and
cougIomerates underiaid by granite, traversed
bv a numerous series OF porphyritie dykes
running east ana "est' "aieh control tns
metallic deposits.
The states are greatly twisted and tilted to
hfph angle and have their principal exposure
on the TANKS of the so Basin" the western
sIoue or rather bluffs OF the Glacier Basin. con-
sistiug of the same group OF rocks broken of
into perpendicular preeiplces, many hundreds
of feet in height, while from me eastern side OF
the basin they have been almost entirely re-
moved. exposiug the granite with abrupt slopes,
hrt not absolutely inaccessible as on the west
eru flank II we draw north aad south line
tbrafrb the center OF the map it would roughly
indicate the junction OF the two rocks, the
western half being a slate aud the eastern q
granite exposure. the fails being on The hoEn-
dary inc outerops OF Amestone are reported
from ire northwest corner OF the map, but have
NOT hon personally examined. n the fact is
correctly stated, it would indicate that the
states bslons 70 an older series than those which
carry the iron ores OF Hamilton. The strike OF
the strati6ed ROCKS is nesrly north and south,
and their dip is probably about 60 deg. 70 the
west
4 The porphyries OF the dykes are OF obscure
tents and structures, snd cannot De certainly
classified without microscopic examination.
They oee,1r As dykes, varying N width from
five TO thirty feet with strike about north -
deg east 70 line east and west, and 4 dip from
perpendicular TO about 90 DEG. east Their
number is very great, there being in ;he seventy
SIX basin AZ least ten in distance of 400 feet.
They decay easier than the states which have
been baked. SO TO speak, by their Intrusion, and
their location is always indicated iu the bluffs
by ravines. often Of great depth. with preeipIt.
Gus sides Each OF these dykes has formed a
vein and much OF the ore is found IN the altered
pOrphyry.
When il is remembered that the ore accom-
pspies these dykes that thev were tutrgs5ous
from below, and that they cut the country al
right angles or nearly 50. . It's structure, ira
versing both the states and the GRANTEES, the
perrnauence OF the veins eonaoE be doubted
The same facts bear on the prodEetlyeaess oi
the mines in depth. IL VIII not be questioned
that the formation Of the veins was prior 70 tat
carving of the country into its present topo
graphical features by the glaciers. OF which ths
remains st;ll exist, 50 that Tie exposures ol ors