The silver star., 1897-04-08

4 parativeiy recent volcanic crater. whose now
rsssS ss %ssOw sSa wa. Gs'
modern stream IL Eagle river. The lays
rom cones Iii formed
elected materials from q distinct crater, Into
crater i: GSs e .6css sS So 81 a. MSs S'
@ sSSs 'sss brush. Sespr prhsrs is m no Visible oStis A
lava iIs 'S. broke I through the frisbie material
| forming tho cone and rushed down through
e. liver ssyes the II empty
Ing. Of Stag from q alag pot.
ne history q u: rsuption briefly is; A. A.
human race. connections Of steam took place.
below this area; the steam forced or found
s:s snd rOss ,sP tSs sed%ssnary ns rsGc
pSiosion: carried yoIumes & the material q
". We 'h have "a aescribed. IN SSo sSoWers :roand tSe
explosions ceased. lava began to rise up in
closely compscted wall and poured, ss We
this eruption was succeeded by great solfn-
teric action afterwards, We have ut present
has been put down in the " bottom on Of the
cratsr but 20 far re 6sieve witnSat @ ,.Y en-
10 basalt, and very hOneycomby or sc0ria
eruption. We have heard OF a crater near
two n The sns San Iusp Sxe sne
der In New Mexico and Arizona compara
lively recent craters and lava flows are not
uncommon. In none OF these however,
have we as yet heard Of any notable discov
cries Of ore. Az these craters are mostly. Of
we mentioned In our previous address, Viz:
bssalt as an ore.bearing form Of lava.
consequence compared with the vast bodies
Of eruptive rock we hnd from one end Of
&c ss ssp sss Gss
Ration Peaks. Trinidad, Or aooding the region
boandaries Of Utah and Ariaons, Or The lie dei IT,
ssn ct sna AZ rp h s
iines Of South Park; and again patches and
Middle Parks. to the boundary line Of wyo
ming. These surface eruptions are mostly
sns ss W ses
are also surface flows OF rhyolite and trachyte
Of more limited character. The basait
heavy lavas; the rhyolite and trachyte gen
orally light colored and light In weight.
Tnsse BEFORE ws refer to are surface ve
currences Of the other form OF eruptive man
Hesitation in Colorado. Wig: that Of the in.
or two striking examples Of the relation O.
these crater or surface eruptions to the oc
currence Of ore bodies.
THE oRIrrED EDtUnNoKksA. 4nEEK AND RosIrA
s, In the % case Of Cripple Greek and Rosita Q,
Silver Clln. although neither Of these iocali
ties show b. existing cones or typical eraters
Iavas came from orinces Of this Kind. II
both cases We have ample proof Of violent
craters whose surface sppearances haSs
been carried away by erosion, leaving only
sita. is covered by sheets Of lava breccia
and tuR Of Just such fragmentary. material
eraers and eapiUsiSe ven rsoT
Cripple Greek there once occurred much Of
the phenomena we have described at Monte
Ing open Of the ground after protfacted
earthquakes, the assures divcrgiu9 from one
or Sre central VENT: the grand a.d re
cloud nled with Its forebodinE storm, which
finally descended in awful cloudbursts Of
roandns reson q srsn,te sIshf1 ss ssd S 1seys
with mudfows Of adobe. formed Of andesits
snd oSst s Late: ss s wa. com
Cured, Which,. andinG the old vsnts ssoked,
tnstezd p bfoa6cilK 6sw SIxitlS. cfsaSst
the nsw wno,s sm regicn g s for %les and alIsd Ii:
hot spring action set in, and the whole ares
with discharges Of various 9ases. smonsst
which that Of 6uor!ne gas was conspicuous.
,rrs These S.,S sasSeou. !nnnences decomPcsed th:s
drew from them the gold :besrinS minsrsis
they contained and depoeited them IN the
snd other o:s:. 5, se:a De
yions eruptive agencies. The conditions Al
Rosita were analogous. varying but slightly
one ptodncins breccis and tais. tsS sstissi sotsci
lava We have rHyote ana srschSs. ~;
sd nsr- ap With Il shs1.s sssa,ss
ssmented. together with a paste formed
nrssy nssyy # eSna.: s.ui 1ss ss;, n ,y
%oss vaIs.Ss sIs sSa: asoss so.wSs' sa:I
IN ana Hnni. e L. Grpp. srppp
where the shaft follows down vertically 4
volcanic throat full Of little lava pebbles,
Greek, 80 at Rosits,. the most striking riki'ixsd I'D
view. Is the soifsteric action THAT that saccesded s Il
leachipg the ores and depositine them 10
means Of the orthodox 6asure kind. but a.
we have, described. In every natural wesi
Ss ,ossne s.s .s ~ ss ssSs:
or space that was open for II.
INTRUSIVE EBUPTIONG.
| Time will not allow us to do iustice "a thai
other. and equally Important FORM of esup. r.
trnnive bodies. and sheets Of lava called lac.
col!uc--one of the. striking examples or
which 10 the Spanish Peaks. The cainps and
regions which illustrate best the laccojitic
nnd intrusive sheet form OF eruption. are
those Of Ieadvilie. Houth Park, the Mosauit0
eion. Hahn's Pesi and Aspen. N. II Il ths it Lead. "a
Vile and South Park region we nnd numer.
Gus enormously thick lnccolitic sheets Of Va.
rions kinds OF pOrphyry intruded between.
and opening M, the leaves Of sediment a ~
strata and sometimes following between
sheets for esirsoTdinary distances. NJ much much
so That az hrst sight such narrow and par.
nllel sheets might readily be taken Tor suc-
censfve enunlve surface lows aIternntjnr
With and covered oyer by sediments; hut
closer examination shows them 70 b. truly
Intrusive. to have been forced In or wedse6
ln and 6own betwcen the beddins pisncs
they have ahundsntly fiuited. the sediment.
ary rocks lying above them. a. would not -
the case had they been surface lows aujetjy
covered BY sciimentary beds. The lava foo.
u massive and crystalline, shoWIna nc
.coriaceous siens. such 40 accompany sur.
face nowa. Hut little evidence of heat on
the strata above or below The lava n sSovn ~
| a. hn :" saoW n