Ellsworth American. [volume] (Ellsworth, Me.) 1855-current, 1880-04-29
Misffll
50
Geological Report of Prof. ". T. Stewart


swan Mine. Franklin. Ne.
The property OF the Swan Mining Com
pany. known a. the Swan Mine. is located
near the village Of Taunton. in the township
Of Franklin. Hancock County. Maine.
A. might be inferred from the foregoing
remarks. the Swan Mine rests in the mids,
Of wide depression. or expansive basin. the
borders of which surround one Of the grand
e.; sheets Of water in .America-markcd on
the maps-Frenehman Bay. The rock cN
po>uFes in the vicinity Of this magnificent
bay. e,eryw here bear evidences Of the ire-
mcndous effect. of glaeia! action. Ga every
hand there are crra;ic boulders. flrrowcd
strata and crodcd channels. In fact. the
entire region affords in19crishablc proof that
Frenohman's Bay owes it. present channel
10 the eroding energy OF moving glacier.
The country TO the eastward Of the Swan
Mine is graniiio-the prevalent species bc
ing hornhlendic Portion, Of this granite
bel; afford excellent building material. and
some iiHe quarries arc IN successful opera
ton a; po:n; near the village OF Taunton.
The mine IS situated at the distance Of about
a mile ives; Of the granite nm. IN the mids;
Of the wide bed sf sch.s;ose rocks, which en-
circle freachnans Bay
This ,la,y bed Is slightly ehloritic, and is
very tough and compact in ieNiur. below
the vea:hered surface. Like mos; of the
arg.laceous rock, IN that region. It contains
mica and shall therefore designate i; a. an
arsilo-fp.caccous schisi.
The lines OF laminaiion IN this bed. are
exceptionally distinct, and may he readily
traced long distance ~i,hou; giving the
slightcs, manifestation OF flcxurc,. or Of local
iauitings.
The yein-s,onc Of the Swan. is a true min
era!ized quartz having surface diameter at
! points OF exposure. Of from one 10 three
feet, and expands rapidly as ii desoends in
/ the schists The strike Of the vein for a
thousand feet or more, ) about north. $
deg. east. by the compass, and ii, average
inclination or Dip is from 81 deg. to IS deg.
below the horizon. Owing to the corrugated
condition Of the enclosing strata. the direc-
ton Of the dip Is very variable There aie
two openings upon the lode. separated by I.
space OF several rods At the mos, north
erly OF these. the dip is toward the east, at
an inclination of 81 deg while a, the prin-
cipal excavation. ward the south, the vein
pitches toward the west at - deg from the
. horizon.
The main shaft Of the Swan mine has
been driven vertically through the lode, and
at the present juncture, has reached the depth
of eighteen feet. The gangue, or vein mat
ter OF the lode at the present working, is
from six to eight feet in lateral diameter
This entire space, except the ore channel is
hllel with reiiculated seams of white quartz,
iron P!r,es and sla,y rocks. In fact, the
materials at this point Of excavation. clearly
indicate rapid and permanent widening Of
the lode. The true ore channel trayerses
the eastern side Of the gangue. and is, at the
present working, from twelve 10 sixteen
inches in width. The ore is compact ar
gentiferous sulphuret of lead, which trav-
erses the quartz in thin bands and dissem-
mated punches. The ore is very rich in
lead, and, as will appear from the accom-
panying certificates Of ASSAY, is also well
charged with silver.
Although the ore channel in the Swan
Mine is, as yet. merely well mineralized
band of silver bearing galena, still. it is un-
questionably true fissure vein, and its en-
tire Theological and geological surroundings
| are sure guarantees Of its permauency and
reliability. In addition to the fact that the
vein is undisturbed by local eruptive forces,
We have the comforting assurance that it trav-
erses system of strata in which ore veins
usually penetrate to profound depths. More
over, experience has proved that mineral
veins enyironed BY this species of laminated
rocks always increase in width and fertility
as depth is reached from the surface. As
yet, the mining exploitation in Eastern Maine
is too superficial to afford striking proofs of
this assertion; but sufficient development
has been made at Sullivan, Bluehill, Acton
and other mining districts, to warrant the
belief that the statement is well founded.
The experienced mining expert always
determines the value and reliability Of an
ore-bearing vein by ascertaining the species
Of rocks which environ it. Rich deposits Of
the precious metals are frequently found i'm
bedded in unstratiied rocks, such as granite
and homogeneous dolomite. Experience
has shown, however, that ore-bodies thus
situated are as a rule, disastrously unrelia-
bic, for the simple reason that they are
merely surface deposits. Compact GRANTEES
present no visible cleavage laminstions, and
hence, ore bodies penetrating them. have no
reliability of either depth or of width. The
same may be stated in regard to dolomitic
limestones. Ore bodies resting in such rocks
are usually found in the condition Of shall
low beds or chambers, and therefore soon
become exhausted. The Trustworthy mines
of the globe usually exist either in deep
| chasms between rocks of different species,