Washington telegraph., 1853-08-31
Remarks OF Julius Froebel,

On the -4ppearaRceof Sloer an northern bfsg.co IN
connection Nth the Geology Of I.1qs
The following remarks, translated from the
San Antplio Crexas) Zeitung may be entitled TO
some interest, and it seems that people, by their
searches icr old mines in Texas uSflaily let thei-
selves be guided by such circumstances and sup
positions rs are generally observed in the discor-
cry of silver ore in Europe:
Ihe geological structure Of the middle conn
tries Of the North American continent is a very
uniform one; and the formations OF Texas. par
ticuariy. are either an immediate continuation or
repetition OF those in the State ol Chihuahua
1t Is therefore wei founded conclusion. that if
silver ore exists IN Texas, II Is b be found under
the same geological circumstances as In the said
parts Of Mexico; and much more SO, lor it is gen
orally known on the banks of the Rio Grande
that the mountains Oh both sides oi the river the
geological structure OF which are perfectly uni
ioriii, DO contain silver ore. 1t is a remarkable
fact tilaL the silver ore discovered in Chihuahua
Is very seldom connected with potiers' ore with
which II IS most generally connected IN other
parts OF the world. In tac Sierra Madre. in the
extreme w' st, silver is mostly found pure. con-
tanning little gold. But although mines ci th!s
kind oi ere are very rich, and although great
masses OF silver ol tais kimd may he found occa-
sionally. veins OF tins kind Iar more difficult
10 work tilan those mixed win p4tters' ore. as
The metal a. them Is more dis ta uied ia the rocks
The silver ere ot the mines OF Central America
contain antiIony and Is easily worked. but as
greater masses oi metal strike te eve il ratural-
~ attracts the attention o.. a superficial and uHu-
stTuctet observer. On the contrary, s1me OF tie
richest silver mines OF CLibtshu:t. lof inslanc..
those oi Santa Eualia from whiei dtrin- their
best yie.d, silyer 10 lie aaaouni ot slgJ.cO0 coo
were taSeH in tie cGuIge Of lew yeaps contain
silver ere which may be overlooked, rot only by
an ordinary observer bat cren hv ruineral6sfsf
IT he be not previously instructed as 20 lis ap-
pearuce.
The silver ores OF Santa Eualia come Crib in
company with, or in the neighboIaood vi carbonic
lead. t'yhte lead oTe] mineral which has no
metalc appearance at all. Even the silver ore
itself does not look like metal and is oniy recog-
nlzabe ia PARTICLES of white, grsv or green color
which are very fine, nlostiy indiscerifihlc with
the naked eye, and distributed throughout the ore
Those silver consist of course OF chloride o.
silver, iodine OF silver and bromide OF silver.
though have not vet had time to subject To
myself in the mines ofSaata Eulalia a hort tirr.s
previous to my departure.
AZ regards the iormatioH Of the mountains in
which slich ores found. 50 Tar as they came
under my observation, found them, in all eases,
lime rock, bordering upon porphyry, or sruroUni-
Ell by porpllyry-f. 2. either in lime k.yers be-
tween pofpoyry. or in solid lime mountains near
the great porphyry structures O. this latter sort
! are the IA acs oi Santa Eulalia.
Hereafter should geological researches be made.
ii would be well 10 be governed to some extent
by said analogles. The same MAY be said of
Central America, so FAR as have had an opportu-
nifty OF obsery ing silver and gold different PAGES.
where silver is mainly found in layers ofantImonv.
the same can also be seen in iroe layers between
pofphyry or in lime rocks near pophyry.