UNJVERSJTY OF CALIFORNIA
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RKSOURCICS
WARREN T. HANNUM, Director
DIVISION OF MINES
W. BURUNG TUCKER, STATE MINERALOGIST
GEOLOGIC BRANCH OLAF P. JENKINS
FERRY BUILDING. SAN FRANCISCO CHIEF GEOLOGIST
SAN FRANCISCO] BULLETIN 134 - PART II - CHAPTER I [DECEMBER 1946
CHROMITE IN CALIFORNIA
PART II — COAST RANGES
CHROMITE DEPOSITS OF THE NORTHERN
COAST RANGES OF CALIFORNIA
By D. H. Dow and T. P. Thayer
Geological Survey, U. S. Department of the Interior
CHROMITE DEPOSITS OF THE NORTHERN COAST RANGES
By D. H. Dow" and T. P. Thayer'*
U. S. DEPAKTilENT OF THE INTERIOR, GEOI-OOICAL SURVEY
OUTLINE OF REPORT
LOCATION AND ACCESSIRILITY 4
HISTORY OF MINING 4
SCOPE OF REPORT AND ACKNOWLEDGMENTS 5
GENERAL GEOLOGY 1 6
CHARACTERISTICS AND OCCURRENCE OF CHROMITE 7
JUNES AND PROSPECTS 8
Colusa County 8
Glenn County 9
Avery claims 9
Black Diamond or Grey Eagle group (1) ; — 9
Conklin and Williams claims (2) 10
Higlj Point mine (3) 10
Manzanita mine (6) 10
Swastika claims (7) 10
Lake County 10
Western group 10
Black Bart (Great AVestern) (1) 10
Brown prospect (2) 11
Butler claims (3) 11
Copsey claims (4) 11
Glad I Found It (5) 12
Gordon Springs deposits (6) ■ 12
Gunn claims (7) 12
Harp and Sons ranch deposits (8) 12
Holmstedt deposits (9) 13
Kangaroo Court mine (10) 13
Mastick ranch deposits (11) 13
Popp and Nichelini claim (12) 13
Schaffer prospect (13) 15
Sutro mine (14) 15
Whispering Pines prospect (15) 15
Young Adams prospect (16) 15
Eastern group 15
Betwixt claim (17) 15
Lucky Strike mine (19) 15
Red Devil claim (20) 16
Smythe or Herman prospect (22) 16
Chromite occurrence (23) 16
Unnamed prospects (24, 25) 17
Cabbage Head or Fir Root Ridge claim (26) 17
Mendocino County 17
Crawford prospect 17
Graham group (1) 17
Guthrie group (2) 18
• Published by permission of the Director, Geological Survey, U. S. Department
of the Interior. Manuscript submitted tor publication April 2, 1946.
•• Geologist, Geological Survey, U. S. Department of tlie Interior.
CHROMITE DEPOSITS — COAST RANGES [Bull. 134 Pt. II
xi S"i<"=^ xf
1 -!-- 3
1 ° «
T"* ! WILLOWSO
^s C L U S A
' ^— --:
'7 16 15 14 13 12 II r
10 9 e 7 6V5 4 3_
\ 5 UKIAH 1
L tW K E f
\ "l 4 "^-e ^ ., \oWilbur Springs '*
Heoldsburg ^ x^^ 9
X SONOMA^" x^'» '%
PRODUCTION X^^ G.e,n..il,. SsiH„eleno _ ^^j °
® Over 1000 tons ^\
S x^" ■" ,, -
• 150 to tOOO tons, ^
•" SANTA ROSA V-, ,
o Less ttian 150 tons, \
,? " (" N A P A
X None, or location uncertoin- \
Numbers refer to fexf descriptions \)^
r^~'\ \ ONAPAC-
] \\ M A R 1 N X^ c-* _ 1
Fio. 1. Index map showing distribution of known chromite deposits in the northern
Coast Ranges of California.
Chap. 1] NORTHERN COAST RANGES 3
Mendocino County — Continued Page
Little Red Mountain (Dunn) deposits (3) 19
Lloyd prospect (4) 19
Moore prospect (5) 19
Shields prospect (6) 19
Unnamed prospect (7) 19
Napa County 20
Northern deposits 20
Black Hawk claim (1) 20
Cigarette mine (2) 20
Crystal Creek claim (3) 20
Pollerhyde claim (4) 20
Ferris claim (5) 21
Graves mine (6) 21
Grey claim (7) 21
Hightower claim (8) 21
Moore mine (9) 21
Mullaly mine ( 10) 22
Nevada claim (11) 22
Turner mine (14) 22
Unnamed prospects (15-17) 23
Southern deposits 23
Astute mine (18) 23
Chrome Center claim (19) 23
Elder claim (20) 23
Fourth of July claim (21) 23
Glad I Found You No. 2 claim (22) 24
Graves ranch deposit (23) 24
Nichelini mine (24) 24
Reeve claims (25) : 24
Claims in vicinity of Samuel Springs (26-30) 24
Sullinger claim (31) 25
Tarry claim (32) 25
Unnamed prospects (33, 34) 25
Sonoma County 26
Barnes mine (1) 26
Gaver prospect (2) 26
Laton mine (3) 26
Madeira claim (4) 27
Red Hill claim (5) 27
Rough Crossing claim (6) 28
Shanks and Copps claim (7) 28
Sonoma Chrome, Inc. (8) 28
Warner and Clark claim (9) 29
Welch prospect (10) 29
Alphabetical list of mines and prospects 29
The chromite deposits in the northern Coast Ranges of California, in Colusa,
Glenn, Lake, Jlendocino, Napa, and Sonoma Counties, have yielded about 50,000
long tons of chromite since the early eighties. One of the first commercially success-
ful chromite mills in the country, located at the Grey Eagle mine in Glenn County,
produced 30,800 long tons of concentrates before the mine was exhausted In 1944.
Except for the Grey Eagle mine, production from this region during World War II
was very small.
The report consists mainly of descriptions of individual mines and prospects
based on published and unpublished information gathered chiefly during the war
years 1918-19 and 1941-43. The general geology of the region and of the chromite
deposits is outlined, and a complete alphabetical list of chromite mines and prospects
4 CHROMITE DEPOSITS COAST RANGES [Bull. 134 Pt. II
The ehromite deposits of the northern Coast Ranfres in California
have yielded about 50,000 long tons of ehromite, of whicli abont 20,000
tons was lump ore and the remainder concentrates. The southern part
of this mountainous area was an important source of ehromite in the
early eigfhties, and one of the largest commercial ehromite milling opera-
tions in the country was successfully completed at the Grey Eagle mine
near the eastern edge of the area. This region, therefore, has had an
important part in the history of ehromite mining in California.
LOCATION AND ACCESSIBILITY
The depo.sits described in this report lie within an area of about
7250 square miles which includes Lake and Mendocino Counties, most
of Napa and Sonoma Counties, and the western edges of Colusa, Glenn,
and Yolo Counties. The area covers the Coast Ranges between the
northern boundary of Mendocino County and an east-west line 40 miles
north of the Golden Gate (see. fig. 1). The region is characterized by
narrow, steep mountain ranges that trend northwest and as a group
rise toward the northwest. The southern part of the area, where the
valleys are wide and the ridges are relatively low, is served by num-
erous highways and rail lines from San Francisco Bay. and supports
about three-quarters of the population of the reaiou as a whole.
The portion north of the latitude of Clear Lake is rugged, and the
peaks attain altitudes of 7000 to 8000 feet ; some areas are almost inacces-
sible. The principal transportation routes in Mendocino County are
TJ. S. Highway 10] and the Northwestern Pacific Railroad, which follow,
the Russian and Eel Rivers. The eastern margin of the region is served
by roads alonsr the west side of the Sacramento Valley. Most of the
roads in the mountains are narrow and graded but otherwise unim-
proved, and ore haulage over them is impractical in wet weather.
HISTORY OF MINING
ehromite deposits in Lake, Napa, and Sonoma Counties are first
briefly mentioned in the report of the State Mineralogist for 1884
(Hanks, H. G. 84, p. 137) with the statement that 2000 tons of ore '
from a deposit of float 4 miles south of Cloverdale, Sonoma County,
was sold by Edward Barnes to three buyers at $7.50 and $10.00 a ton.
The cost of the ore on the dock at Petaluma was said to be $3.50 a ton.
The produc+ion from the northern Coast Ranges up to 1900 is estimated
at about 7300 tons; the accuracy of this estimate is indicated by the
following statement (Hanks, II. Q. 84, p. 138") :
"In attempts to g.iin information as to the quantit.v uf [chniinite] ore raised
in California, the State SlineraloKist has met with so much opposition from those
who are interested to conceal the amount that no reliable data can lie given."
The total production appears to be slightly more than 50,000 long
tons (see table 1).
During the period 1916-20 ehromite production was stimulated
in the region as a whole by wartime demands, and in the southern part
by the needs of a tannery at Napa. The operators of the tannery, the
Sawyer Tanning Company, purchased high-grade ore either delivered
at the plant or at the mine, and leased and operated a few mines in
NORTHERN COAST RANGES
Table 1. Shipments of chromite ore and concentrates from northern Coast Ranget of
California, by counties, from 1915 to 19^^ (in long tons)
1938 . . .
** Includes 6 tons from Colusa County.
Napa and Sonoma Counties. Shipments ofSeially reported to the
Geological Survey during these years amounted to 8200 long tons, in
addition to which production in Glenn County during 1916 was esti-
mated at 3000 long tous^. The shipments reported in 1920 probably
came from stock piles left at the mines at the end of the war.
Shipments between 1935 and 1943 were from two main sources.
The 565 tons shipped from Napa County between 1935 and 1941 prob-
ably was taken in part from mine stocks estimated at 655 tons at the
end of 1918. The Glenn County production in 1942, 1943, and 1944
came entirely from tlie mill operated at the Grey Eagle mine by the
Rustless Mining Corporation.
Most of the chromite shipped, except that from the Grey Eagle
mill, was high-grade ore averaging 45 percent or more Cr203, and was
mined from small deposits. The mill at the Grey Eagle mine treated
ore from the Grey Eagle and Black Diamond No. 11 claims, and pro-
duced concentrates which averaged about 46 percent CrjOa with a
chromium-iron ratio of 2.67.* Although a few deposits of dissemi-
nated ore, in addition to the Grey Eagle deposit, have been mined,
shipments have been limited to sorted high-grade ore.
SCOPE OF REPORT AND ACKNOWLEDGMENTS
Although substantial amounts of chromite have been shipped from
the northern Coast Eanges, the Grey Eagle is the only mine that has
been worked on a large scale since 1918. As the high prices during
"World War II failed to stimulate production in this region, exami-
nations made as part of the chromite investigations of the Federal
' Diller, J. S. 19. p. 31, and unpublished data of the U. S. Bureau of Mines.
•Rustless Iron and Steel Corporation, written communication, 1945.
6 CHROMITE DEPOSITS — COAST RANGES [BuU. 134 Pt. II
Geological Siirvej' were limited to a few of the larger mines, and no
systematic attempt was made to visit all reported chromite prospects.
Many prospects, however, were examined and accurately located during
geologic mapping of serpentine masses in connection -n-ith the Survey's
quicksilver program. The present report is based on examinations of
the larger deposits by Survej' geologists between 1941 and 1945, and
on unpublished data gathered by engineers of the U. S. Bureau of
Mines, the California State Council on Defense,^ and the State Division
of Mines between 1916 and 1918. Although much of the information
is sketchy and incomplete, it seems desirable that the available data be
compiled and made a matter of public record. The descriptions of
deposits, accordingly, include the most complete information available,
which in many instances was obtained when the mines were in operation
during World War I. Deposits for which descriptions and maps have
recently been published are not redeseribed in this report, but refer-
ence is made to the publication in which the description appears. As in
most mining districts, many reports of production are contradictory
and cannot be reconciled ; the reader therefore may find unexplained
discrepancies between officiallj' reported and unofficially estimated pro-
duction from certain deposits. The tables show only production reported
to the Geological Survey or Bureau of Jlines for the annual volumes of
Mineral Resources of the United States.
This summary has been compiled by D. H. Dow and T. P. Thayer
from reports, published and unpublished, by F. G. Wells, P. W. Cater,
Jr., and Fred Gros, of the Federal Geological Survey; F. B. Caldwell
and others of the Federal Bureau of Mines; and E. F. Davis of the
Committee on Geology and Mineral Resources of the California State
Council on Defense. Most of the information dating from World War I
was compiled as a project of the Works Progress Administration, under
the auspices of the California Di\asion of Mines and the supervision of
Olaf P. Jenkins, Chief Geologist.
Although the northern Coast Ranges have been mapped only in
part, the}' are known to be geologically similar to the central Coast
Ranges, which have been well studied in the search for oil, and were
described by Taliaferro (41).
The bulk of the ranges is made up of rocks of the Franciscan group
and Knoxville formation of Upper Jurassic age. The Franciscan group
is composed of many different kinds of rocks, the chief ones being
arkosie sandstone, radiolarian chert, pillow lavas, basic and ultramafic
intrusives, and metamorphic rocks closely related to glaucophane schist.
The Knoxville formation contains rocks similar to the Franciscan, which
it overlies, but in most places consists mainly of shale, with sandstone
and conglomerate in less amounts. The ultramafic rocks or serpentines
which carry the chromite deposits were intruded into the sedimentary
series as sill-like sheets, which are most numerous and largest in the
upper part of the Franciscan group and the lower part of the Knox-
ville formation. The serpentines have been intruded by dioritie and
more basic rocks which grade into diabase.
•For a description of the work of this Council, see Jenkins, O. P. 43, pp. 9-10.
Chap. 1 J NORTHERN COAST RANGES 7
Younger rocks, whieh range in age from Cretaceous to Recent and
sliow great diversity, are present in many parts of the region.
The structure of the ranges is dominated by folds and faults which
break the rocks into narrow blocks that trend north-northwest. The
serpentines form lenses up to 15 miles loug by 2 miles wide and are
distributed in irregular belts parallel to the major folds and faults.
Many of the lenses are localized along the contact between the Fran-
ciscan group and Knoxville formation; they commonly dip more steeply
thau the enclosing formations, and therefore are not true sills.'*
The serpentines were derived from chromite-bearing peridotitic
rocks by alteration which may have immediately followed intrusion or
may have been much later. The original rocks appear to have been
mainlj' saxonite, composed of olivine and enstatite, accompanied by
subordinate masses of duuite and pyroxenite. Although some of the
intrusive bodies are massive, most of them are sheared, especially along
their contacts. The contacts between serpentine and country rock have
been faulted in many places, probably by movements which took place
after the rocks had been serpentinized. Some of the serpentine has
been converted into a hard silica-carbonate rock in which many quick-
silver deposits have been localized. For a fuller discussion of the
general geology of the region, and detailed descriptions of areas in
which geological relations are well shown, the reader is referred to two
recently published reports on quicksilver deposits by Paul Averitt (45)
and R. G. Yates and L. S. Hilpert (46) of the Geological Survey.
CHARACTERISTICS AND OCCURRENCE OF CHROMITE
The only ore mineral in the chrome deposits is chromite, a dark,
submetallic mineral which is characterized by a bro\vn streak and
specific gravity ranging from about 4.1 to 4.9. Its composition is
indicated by the general formula (Mg,Fe) (Cr,Al,Fe)204; cleaned chro-
mite from Coast Range deposits averages 50 to 55 percent Cr203, and
has a chromium-iron ratio between 2.5 and 3.2. Chromite occurs as
irregular pods and lenses in dunite — a rock composed entirely of
olivine — or its altered equivalent. High-grade ore consists of massive
chromite mixed with a minimum of gangue ; low-grade ores are mix-
tures of chromite and gangue in various proportions, and commonly
grade into barren dunite or serpentine. In districts which, like the
Coast Ranges, have been highly deformed, the bodies of high-grade ore
usually are bounded by faults and can be readily mined out. Bodies
of low-grade or disseminated ore, however, may be intimately mixed
with barren serpentine by complex faulting and therefore may be
difScidt to mine.
The chromite deposits in most peridotites appear to be distributed
at random, and no reliable guides to concealed ore bodies have been
found. Man}' ore bodies are alined in shear zones, probably as a result
of shearing of large deposits into a number of smaller lenses. In those
places, therefore, where shear zones are kno\vn to contain ore bodies,
prospecting should be concentrated along the strike of the zone. Most
shear zones, however, are probably not much more favorable prospecting
ground than any other parts of a given peridotite mass.
'Yates, Robert, personal communication, 1945.
8 CHROMITE DEPOSITS — COAST RANGES [BuU. 134 — ^Pt. II
The lack of response of mining in the nortliern Coast Ranges to
high prices for chromite is probably the best index to the reserve situa-
tion. The accessible parts of the region, particularly in Napa and
Sonoma Counties, have been thoroughlj- prospected, aud the high-grade
ore bodies have been mined out. The largest locally known low-grade
ore body, at the Grey Eagle mine, has also been exhausted. The pos-
sibilities for future production therefore would seem to be limited to
i-elatively small low-grade deposits that are accessible, and to undiscov-
ered deposits in unprospected areas. The estimates of reserves given
may be changed considerably by future developments, for information
on most low-grade deposits is incomplete.
The reserves of milling-grade ore are estimated as equivalent to
about 4400 long tons of Cr203 or 8800 long tons of concentrates con-
taining 50 percent Cr203. The approximate quantities of ore of various
grades are as follows : 4000 long tons averaging 20 percent ; 29,000 tons
averaging 12 to 13 percent ; 5000 tons averaging 10 percent ; and 12,000
tons averaging 6 percent CraOs. More than half of these reserves are in
12 deposits in the vicinity of the Grey Eagle mine, and the rest are in
the Laton, Sonoma Chrome, Inc., and Ilolmstedt mines, in Napa and
Sonoma Counties. Development of significant reserves, even of miUing-
grade ore, obviously, depends on new discoveries.
Discovery of large deposits of high-grade ore in Napa, Sonoma, and
southern Lake Counties seems improbable. The high prices during
World War I apparently led to exhaustion of many deposits, and the
Sawj^er Tanning Company mined out most of those remaining at the
end of the war. The lack of new discoveries of high-grade deposits
between 1941 and 1943, in view of government aids such as access roads,
does not augur well for future production, even in less-explored areas.
MINES AND PROSPECTS
In the following descriptions, the deposits are numbered and
arranged alphabetically by counties. The names most commonly used
appear first, followed in parantheses by others by which the deposit
may also be known currently. Deposits which are identified by num-
ber on the Economic Mineral Map of California^ are indicated by the
corresponding number in brackets.
The source of unpublished information on deposits is indicated by
the name of the person reporting, followed by the initials of the organi-
zation and the last two figures of the year in which the mine was
examined. The abbreviations used are as follows: G.S., Geological
Survey, Department of the Interior; B.M., Bureau of Mines, Depart-
ment of the Interior. All published and some unpublished reports to
which reference is made (i.e. Averill, C. V. 29, etc.), are listed in the
Bibliography at the end of this report.
Six chromite prospects in Colusa County, none of which appar-
entty has shipped any ore, are listed in Bulletin 76 of the California
State Division of Mines (Bradley, W. W. 18, pp. 123, 124). Three of
' Outline geologic map of California showing locations of chromite properties ;
Economic Mineral Map of California, No. 3 — Chromite : California Div. Mines, 1942.
NORTHERN COAST RANGES
these, the Chrome Wonder (1), Liberty chrome mine (3), and Teathers
chrome prospects (5) are in the vicinity of Stony Ford (T. 18 N.,
R. 6 W.") and may be the ones to which Taliaferro ("C.S.C.D. 18) refers
as near Fonts Springs (T. 17 N., R. 7 W.). The F. C. Innes pros-
pect (2) was reported to be near Wilbur Springs (T. 14 N., R. 5 W.),
and the Princess chrome mine (4) about 1^ miles northwest of Cook
Springs, in T. IG N., K. 6 W. No location was given for the Stella
chrome mine, owned by Elmer and Geoi'ge Evans of Sites.
Avery Claims. — Oscar Avery was said to have three claims 18 miles
from Fruto, from which he had mined 80 tons of disseminated ore.
R. D. Adams and Company sampled the deposit, but apparently found
it to be too low grade to work. The distance from Fruto suggests that
this deposit may be near the Black Diamond group, but because of the
uncertaintv in location it has not been plotted on the index map.
(Thompson, H. 18.)
Blaclt Diamond or Grey Eagle Group (1) [87,88]. The Black
Diamond or Grev Eagle group of claims covers a number of chromite
deposits in sees. 13, 14, 24, and 25, T. 22 N., R. 7 W., and see. 19, T. 22
N., R. 6 W. For simplicity in description, the following claims are
included in this group, although they belong to various owners : Black
Diamond, Black Diamond Nos. 2 to 12, Boulder City, Emmeline, Grey
Eagle, Grey Eagle Extension, Hooligan, Hospital Ridge, Katherine,
Loleta, Manzanita, Manzanita Extension, and Mary Ellen. As all the
deposits on these claims were mapped in detail and described as of
January 1, 1944, only the developments since then will be reviewed here.
The Rustless Mining Corporation mined 135,800 long tons of ore
from the Grey Eagle mine and 640 long tons from the Black Diamond
No. 11 claim between February 1942 and March 1944. The ore was
mined in open pits, and about 878,000 long tons of overburden was
handled, making the ratio of wa.ste to ore about 6.5 to 1. The ore aver-
aged 13 percent Cr^Os and the mill produced 30,806 long tons of con-
centrates averaging 46 percent CroO.^, indicating a recovery of slightly
more than 80 percent of the chromite. The tailings averaged 3.33 per-
cent CroOs. Exhaustion of the Grey Eagle and Black Diamond No. 11
deposits forced the mill to close down, and the inability of the Rustless
Mining Corporation to mine the nearby deposits when it had the mill in
operation does not seem promising for the future of the district. (Rynear-
son and Wells 44.)
» Meridian is Mount Diablo throughout.
Shipments of chromite from Glenn County mines, 1916-44 (in long tons)
Grey Eagle and Black
Diamond No. 11
10 CHROMITE DEPOSITS — COAST RANGES [Bull. 134 Pt. II
Conklin and Williams Claims (2) . — Claims were held by Wells Conk-
lin and Ed Williams of New^dlle on two deposits three quarters of
a mile apart in sec. 3, T. 22 N., R. 7 W. A ehromite lens 2 feet wide
was exposed on one claim, and about 100 tons of high-grrade ore had
been mined from six lenses on the other claim. None of the ore had
been shipped in 3918. (Bradley, W. W. 18, p. 147.)
High Point Mine (3). — The High Point mine is described as in the
Newville mining district, 32 miles west of Orland. There were three
claims on a deposit on top of a rough barren mountain, where open
cuts exposed the main deposit over a length of 250 feet. The ore con-
sisted of irregular streaks of disseminated ehromite, and the ore body
as a whole was said to strike north and dip 60° W. The grade of the
ore averaged less than 40 percent Cr203 and reserves were estimated as
200 tons of blocked-out ore, 250 tons of probable ore, and 1000 tons of
possible ore. Apparently the deposit contained very little ore of ship-
ping grade. (Thompson, H. 18.)
Mamanita Mine (6). — The IManzanita mine is in the NE:J sec. 31,
T. 22 N., R. 6 W., on the Cushman ranch. The workings were caved
in 1942, but available evidence indicated possible reserves of milling-
grade ore in excess of 1000 tons. The mine yielded 79 long tons of
lump ore in 1917. (Rynearson and Wells 44, p. 22.)
Swastiha Claims (7). — The Swastika claims in sees. 4 and 5, T. 18
N., R. 6 W., 4 miles north-northwest of Stonyford, were owned by
A. B. Brune and leased to A. H. Noyes in 1917. A deposit of exceed-
ingly fine-grained, high-grade ore was opened up by an open cut and
a short tunnel. The ehromite occurred as small irregular pockets in
soft light-green serpentine. About 40 tons of ore had been mined and
10 tons was exposed in the tunnel in August 1917. (Taliaferro, N. L.,
in Louderback, G. D. 18.)
Twenty-seven ehromite mines or prospects in Lake County have
been examined and described bj^ State or Fedei-al engineers or geol-
ogists. With the exception of the Cabbage Head claim in the northern
part of the county, the deposits fall into two groups, western and
eastern. The western group is rather indefinite, but the eastern is well
defined and apparently related to a major belt of serpentine which
extends southward into northeastern Napa County. The deposits
included in the southeastern corner of the western group are, likewise,
in the northern end of a serpentine belt which extends into Napa
County (see fig. 1). The descriptions of deposits, accordingly, are
arranged alphabetically in two groiips.
Black Bart (Great Western) (1) .— The Black Bart mine is in
see. 16, T. 10 N., R. 7 W., on patented land o^vned in 1942 by W. B.
Shepherd of Monticcllo and leased to the Anglo-American Mining Com-
])any, of Clovis. It is on a steep hillside about 2400 feet above tide and
several hundred feet above the Great Western quicksilver mine.
Reports of production differ: in Bulletin 76 (Bradley, W. W. 18, p.
149) the mine is credited with 125 tons of ore carrjung 45 to 50 per-
cent CroOa, but Davis (Louderback, G. D. 18) said it shipped 400 tons
of ore averaging 48 percent CroOs. Davis' figure seems rather high,
Chap. 1] NORTHERN COAST RANGES 11
Shipments of chromite from Lake County mines, 1916-^3 (in long tons)
Mine or shipper
Thn nporp (T Smvthpl*
• Source of ore or location of mine uncertain.
althoiiirh it is probable that at least 150 tons were shipped to the Sawyer
The ore ranged from massive high-grade chromite to low-grade
disseminated ore. and from 20 to 50 percent CroOs. The high-grade ore
was very irregularly distributed in the various ore bodies, and much
of it was broken and friable. Most of the contacts between ore and
serpentine were faulted, and the serpentine wall-rock was highly sheared.
Mining was started in IftlS on a massive chromite lens 10 to 15 feet
long by 5 to 6 feet wide, which trended east and apparently dipped
south. " The east end of this lens split into three stringers each up to
a foot tliicl; ; all were followed 40 to 50 feet. A series of drifts were
driven on about 20-foot levels, the lowest 50 to 55 feet below the surface,
with a number of cross-cuts and raises. The workings appear to have
been driven at random, and suggest that several irregular ore bodies
were mined, some of them up to the surface.
Operations in 1942 were limited to cleanins out some of the old
workin-^s. (Gros, F., G. S. 42; Caldwell. P. B. 18; Davis, E. F., in
Louderback, G. D. 18; Bradley, W. W. 18, p. 149; Diller, J. S. 20,
Broirn Proftpcci (3). — Chromite float was found in sec. 29, T. 12
N., R. 8 "W., on land o-i^ed by J. H. Bro^Ti of Cobb. Although a large
quantity of float was scattered about, none of it had been gathered and
no prospecting had been done up to the time of Davis' visit (1917).
(Davis, E. F., in Louderback, G. D. 18.)
Bidler Clainut C.3).—\Y. E. and Theresa Butler of Middletown had
two claims, probably in sec. 24, T. 10 N., R. 6 W., three-quarters of
a mile from the Calistoga road at a point about 12 miles from Calistoga.
A total of 16 tons of ore from these claims was sold to the Sawyer
Tanning Company in 1918. A chromite lens IJ feet wide was exposed
over a fengtli of 4 feet in a pit on the southern claim when examined
by Davis. This ore was estimated to contain 45 percent Cr^O.^. On the
northern claim, held by Theresa Butler, lenses striking about N. 30° E.
and dipping 65° W. were mined by an 8-foot trench and 18-foot inclined
shaft. The ore was estimated to range in srade from 38 to 50 percent
Cr^O.,, and the ore mined averaged 48 to 50 percent. (Davis, E. F., in
Louderback, G. D. 18.)
Copsey Claims (4). — The Copsey group of three claims — the Uncle
Josh, Manzanita, and Mint— was located in 1918 by Arthur Copsey of
Middletown, who leased shares to W. P. Moore and Joshua Spiers. The
claims cover a number of chromite deposits that occur in a belt that
extends about N. 65° W. from the northern part of sec. 4, T. 11 N.,
12 CHROMITE DEPOSITS COAST RANGES [BuU. 134 Pt. II
R. 7 W. into the SW^ sec. 33, T. 12 N., R. 7 W. The workings are
a quarter to IJ miles from the main road at a point 7 miles from
Middletown and 23 miles from Calistoga.
A good deal of black chromite sand, but relatively little lump ore,
was found on the claims. The largest lens of high-grade ore yielded
less than 10 tons. Most of the lenses are of disseminated ore and dip
about 40° S.
About 20 tons of ore was mined from several lenses on the Man-
zanita claim in 1917 and sold to the Union Chrome Company. Although
chromite sand occurred over an area about 500 by 600 feet on the Uncle
Josh claim, several trenches and tunnels indicated that the main stringers
and lenses were restricted to an area 20 to 50 feet wide. Little work was
done on the Mint claim, although there was some float. (Gros, F., G. S.
42; Davis, E. F., in Louderback, G. D. 18; Caldwell, F. B. 18; Aubury,
L. E. 06, p. 362; Bradlej^ W. W. 18, p. 148.)
Glad I Fojmd It (5). — The Glad I Found It claim is near the
county line and about half a mile from the Butts Canyon road between
Middletown and Lower Lake. It is probably in sec. 24, T. 10 N., R.
6 "W. Three tons of ore from this claim was sold to the Sawyer Tanning
Company. (Davis, E. F., in Louderback, G. D. 18.)
Gordon Springs Deposits (6). — Chromite float was found at two
places in sec. 2, T. 11 N., R. 8 W., about a quarter of a mile from the
Calistoga-Kelseyville road and 25 miles from Calistoga. In 1918 the
land was owned by Mrs. Laura Miles of San Francisco and Mrs. Irene
Anderson of Petaluma, who refused to allow prospecting or mining
on their land.
A few blocks of chromite occur at one place, and at the other about
200 pounds of ore in chunks up to 10 inches in diameter was scattered
over a few square yards. The ore was said to be unusually massive, and
to have a glassy luster on freshly broken surfaces; it may be a high-
alumina variety, for it assayed only 37.8 percent CroOg. Davis believed
that the float must indicate a small ore body in place and recommended
surface trenching. (Davis, E. F., in Louderback, G. D. 18.)
Gunn Claims (7). — J. A. Gunn of Kelseyville located 5 claims, the
Lakeview, Helen Ray, Mummu, Juniper Ridge, and Popgun, in see. 14
and the BWi see. 11, T. 12 N., R. 9 W., 8 miles south of Kelseyville.
The Bruce claims, which were recorded as in sees. 18 and 19, T. 12 N.,
R. 8 W., and also belonging to Gunn, are believed to be the same.
The chromite was found as float and in small lenses trending north-
west. The lenses contained up to a ton of ore, and most of it was mas-
sive. A total of 17 tons was mined and shipped to the California
Chrome Company, the average grade being 38 percent Cr.jOj. About
7| tons was mined from both the Helen Ray and Juniper Ridge claims,
and 2 tons of float from the other three. (Davis, E. F., in Louderback,
G. D. 18.)
Harp and Sons Eanch Deposits (8). — The Sa-^vA-er Tanning Com-
pany mined about 50 tons of ore, which was said to have contained
50 to 52 percent CtsOx, from open cuts in see, 20, T. 11 N., R. 7 W., on
the Harp and Sons ranch. The chromite occurred in small lenses,
which had been mined out bv 1918. (Bradlev, W. W. 18, p. 149 ; Averill,
C. V. 29, p. 341.)
Chap. 1] NORTHERN COAST RANGES 13
Hohnsiedt Deposits (9). — The Holmstedt deposits are in sec. 22,
T. 10 N., R. 7 W., on land owned by Victor Holmstedt and Van Warner
of Middletown, and leased in 19i3 to J. H. Scott Company of San
Francisco. They are 4 miles south of Middletown, near State High-
way No. 29. A small amount of ore is said to have been shipped from
here during "World War I.
The chromite deposits occur in serpentinized peridotite in a zone
which is about 250 feet long, 30 to 35 feet wide, and trends north.
As shown in figure 2, the zone has been explored by a number of trenches
and drifts. A series of caved trenches to the southeast suggests a con-
tinuation of the zone, that lies at an angle of about 45° to the main part.
The chromite occurs as small lenses up to a foot in width and as layers
of disseminated ore 1 inch to 3 feet wide, separated by essentially barren
serpentine. The laj-ers strike parallel to the long axis of the zone, but
dip southward at various angles; this structure suggests folding.
A sample of average ore analj'zed in the Geological Survey laboratory
assayed 16.09 percent CraOa, and had a chromium-iron ratio of 1.63.
As cleaned chromite from the same sample contains 52 percent CrgOs
and has a chromium-iron ratio of 2.53, a commercial concentrate averag-
ing 45 percent CroOs with a chromium-iron ratio of 2 or more probably
could be produced.
The ore bodies consist of swarms of small lenses and laj^ers, and are
estimated to be made up of about 40 percent of chromite-rich layers
and 60 percent of barren serpentine. The average grade of the ore is
therefore about 6.5 percent Cr203 or 13 percent chromite. The trenches
at the north end exposed a bodj^ of chromite about 60 feet long by 18
feet wide to a depth of about 8 feet. The layering in this body dips
70° to 80° S. The south ore body has been explored by four trenches
that continue into the hill as adits ; the southernmost one gives a section
100 feet across, and at the face is 40 feet below the surface. The south
ore bod}^ is about 120 feet long by 45 feet wide and at least 25 feet deep.
About 40 feet of relatively barren serpentine lies between the two ore
bodies. (Phoenix and Cathcart, G. S. 43.)
Kangaroo Court Mine (10). — The Kangaroo Court mine was worked
in 1918 by its owners, E. L. Wilkinson of Middletown, and C. L. Russell
of Calistoga. It Ls on a rather steep slope in sec. 25, T. 10 N., R. 7 W.,
500 feet from the road and 12 miles from Calistoga.
Small chromite lenses containing up to a ton of ore and connected
by narrow stringers were found in a shear zone striking northwest and
dipping northeast. About 15 tons of ore averaging 40 percent Cr203
was mined from an open cut and a short tunnel and sold to the Sawyer
Tanning Companv. Xo ore was visible when Caldwell visited the mine
in July 1918. (Caldwell, F. B. 18 ; Davis, E. F., in Louderback, G. D. 18.)
Mastick Ranch Deposits (11). — Massive chromite float was found
in several places on the Mastick ranch, which in 1918 included about
14,000 acres of patented land. The northwesternmost deposit was in
sec. 3, T. 10 N., R. 6 W. As the owners refused to lease mining rights,
the deposits were not prospected systematically and no shipments have
been reported. (Caldwell, F. B. 18.)
Popp and Nichelini Claim (12). — Davis reported that in 1918 F. W.
Popp and William Nichelini of Calistoga shipped 40 tons of chromite
from a deposit in sec. 13, T. 12 N., R. 8 W. Davis did not examine the
CHROMITE DEPOSITS — COAST RANGES [BuU. 134 Pt. II
Serpcnlinized ond locolly
Approximate limits of
ore zone on surface
Pit or trench
CONTOUR INTERVAL 10 FT.
Pits filled witti debris
very little ctiromite
GEOLOGY BY 0. A. PHOENIX AND J.BCATKCART, 1943
Fig. 2. Geologic map of the Holmstedt chromite deposit.
Chap. 1] NORTHERN COAST RANGES 15
deposit as he was told it had been mined out. (Davis, E. F., in Louder-
back, G. D. 18.)
Schaffer Prospect (13). — F. Schaffer, of Kelseyville, found small
amounts of chromite on his propert.v in sec. 36, T. 13 N., R. 9 W., 4 miles
southeast of Kelseyville. Davis indicated that the ore appeared to be
of good quality but did not examine the deposits. (Davis, E. F., in
Loiiderback, G. D. 18.)
Suiro Mive (If). — The Sutro mine is in the southeast corner of
see. 26, T. 10 N., R. 7 W., half a mile from the road and 11 miles fi-om
<\distoga. In 1918 F. W. Popp and AVilliam Nichelini of Calistoga had
leased the mine from the owner, Charles Sutro of San Francisco.
Numerous lenses of chromite from a few inches to 3 or 4 feet in
thickness were found strung out in a shear zone striking N. 35° E.
and dipping 45° NW. The ore-bearing zone was 3 to 5 feet wide and
was followed 30 feet in an open cut and 12 feet down the dip by an
inclined winze. Most of the ore was soft and friable with well-defined
eontacts against serpentine. About 12 tons of 42 to 45 percent ore
Two other ore bodies were found about 1000 feet southeast of the
main workings. One of these was a small mass of high-grade ore, but
the other was low-grade and contained about 20 percent CrnO.-j. The
low-grade body had been only partly explored. (Caldwell, F. B. 18;
Davis, E. F., in Louderback, G. D. 18.")
Whisjiering Pines Prospect (15). — David Streckler found chro-
mite on his land in sec. 14, T. 11 N., R. 8 W., 8 miles north of Middle-
town. Although float was found in several places, the only ore dis-
covered in place was an 800-pound lens exposed by a trench near his
house. (Davis, E. F., in Louderback, G. D. 18.)
Young Adams Prospect (16). — The Young Adams prospect is near
the center of sec. 12, T. 12 N., R. 9 W. Except for the eollection_ of
5 tons of high-grade float ore which was sold to the Sawyer Tanning
Companv, little work has been done on this prospect. (Davis, E. F., in
Louderback, G. D. 18.)
Betwixt Claim (17).- — The Betwixt claim is one of a group of three
claims located in 1918 by G. B. Smith and P. B. Edwards of Lower
Lake. The claims are a short distance south of Reiff, in T. 12 N.. R. 5 "W.,
and were located by sections as follows: Betwixt, SE:| sec. 30; E.Z., sec.
29 ; and Riverside NTV'i see. 29. About 500 pounds of ore was found
in loose and broken serpentine on the Betwixt claim ; 200 pounds of high-
grade float was found on the E.Z. claim; and the Sawyer Tanning
Company mined 4 tons of high-grade ore from the Riverside claim for
a rovaltv of $3 a ton. The claims were abandoned in 1918. (Davis,
E. F., in Louderback, G. D. 18.)
Lucky Strike Mine (19) .- — The Lucky Strike mine is in sees.
13 and 24, T. 12 N., R. 6 W., 7 miles by road from Reiff. It is on a
gentle grassy slope at an elevation of 2300 feet, a mile west of, and 400
feet above, the floor of Morgan Valley. In 1942 the mine was owned
by TV. B. Shepherd of Monticello and leased by the Anglo-American
16 CHROMITE DEPOSITS — COAST RANGES [Bull. 134 — Pt. II
This mine has been the most productive chromite mine in Lake
Count}', and is credited with shipments of between 1350 and 2000 tons.
Although accounts differ on the amount shipped in 1918, all agree that
1350 to 1450 tons was shipped to the Sawyer Tanning Company in
1916 and 1917. No shipments have been reported since 1918.
The workings consist of 25 to 30 pits and open cuts and a few short
drifts, concentrated mainly in an area 1000 feet long by 100 feet wide.
The largest cut is about 200 feet long, 20 feet wide, and 35 feet in
greatest depth ; the next largest is about 40 feet long. Very few of the
workings show any ore.
The ore is black, massive, coarse- to fine-grained chromite; all of
the ore shipped contained 43 percent or more CroOa and 90 percent of
it is said to have exceeded 48 percent CroOs. The ore formed well-
defined lenses with sharp contacts. The main production came from
a large kidney-shaped mass which was over 100 feet long, 18 feet in
greatest width, and 35 feet deep; it yielded about 1000 tons. The
40-foot cut is said to have yielded 200 tons from a single ore body.
The ore bodies were said to trend N. 45° to 65"^ W. and dip steeply to
the north or south.
Exploration in 1942 had uncovered 5 lenses alined parallel to the
main zone and 30 feet to the southwest. The largest ore body was 20
feet long, up to 15 feet wide, and only 5 feet deep where exposed in
a 35-foot shaft. The other 4 lenses averaged about 5 feet in length
and 2 feet in width. (Gros, F., G. S. 42; Bradley, W. W. 18, p. 149;
Averill, C. V. 29, p. 341; Diller, J. S. 19, p. 31; 20, p. 664; Caldwell,
F. B. 18; Davis, E. P., in Louderback, G. D. 18.)
Red Devil Claim (20). — Davis reported that the Red Devil claim
was 2^ miles northeast of the Lucky Strike mine and south of Lower
Lake. He did not visit the deposit, and the location given him seems
to be in error, for the Lucky Strike mine is 7 to 8 miles southeast of
Lower Lake. The deposit j'ielded 15 tons of ore in 1917. (Davis, E. P.,
in Louderback, G. D. 18.)
Smythe or Herman Prospect (22). — The Smythe and Black Dia-
mond prospects are about 1000 feet apart in sec. 28, T. 11 N., R. 5 W.,
a quarter to half a mile from the main road. They are near the southern
end of a serpentine mass 4 miles long by a mile -wide. Development
was retarded by a dispute over ownership in 1918, and no ore is known
to have been shipped. August Herman claimed both prospects, Joe and
Frank Ehoda claimed the Black Diamond, and Tom Smj-the claimed
In 1942 Gros reported that 4 small ore bodies apparently had been
mined out on the Smj'the or Herman claim, and only one was seen in
place. This ore body was about 10 feet long, 5 feet wide, and 10 feet
deep at the exposed end.
Chromite boulders were scattered over a distance of 60 feet in
an east-west line across the top of the hill on the Black Diamond claim,
but no prospecting had been done. (Gros, P., G. S. 42; Caldwell,
F. B. 18.)
Chromite Occurrence (23). — Davis mentioned chromite float in sec.
35, T. 14 N., R. 7 AV., just below the road from Lower Lake to Arabella.
Glaueophane schist was exposed in the road and in a ledge 50 feet
below it. The surface debris below the ledge contained pieces of chro-
NORTHERN COAST RANGES
mite up to 6 inches across. The ore appeared high grade and contained
nnmerons masses of nvarovite, or chrome garnet. (Davis, E. F., in
Londerbaek, G. D. 18.)
Unnamed Prospects (24, 55). — Dnrin? mapping of the Knoxville
quicksilver district small chromite shovrintrs were noted in the SWi sec.
33, T. 12 N., R. 5 W., and in the NW^ see. 3, T. 11 N., R. 5 W. The first
of these occi:rrences consists of about 100 pounds of chromite in an expo-
sure of serpentine and the second is of the same order of magnitude. The
names and owners of these prospects are not known. (Averitt, P., G. S.
Cahhnqc Head or Fir Jxonf Nidfie Claim (26). — Dave Dondero and
W. M. JIcLeod, of Hullville, both claimed some small deposits of fine-
grained chromite in sec. 32, T. 19 N., R. 9 W., in northern Lake County.
About a ton of ore had been picked up when Caldwell visited the claim
in 1918, but there is no record of any shipment. (Caldwell, F. B. 18.)
The known chromite deposits in Mendocino Count.v appear to be
relatively small, and development of the principal prospects is handi-
capped by lack of roads. Comparison with Del Norte County, however,
which is equally iindeveloped, indicates that if the deposits in Men-
docino County were large, production from 1940 to 1944 would have
far exceeded the 2.5 tons reported.
Two main Erroups of deposits are known, both of them on "Big
Red Mountain." It should be noted, however, that there are two Big
Red Mountains, one southeast of LTkiah. in the southeastern part of the
county, and the other west of Cummings, in the northwestern part.
Crawford Prosvcct. — Davis and Woodford reported that W. L.
Crawford removed 2 tons of chromite from his ranch at Largo, 9 miles
south of Ukiah. No other information was given. (Davis and Wood-
ford, in Louderback, G. D. 18.)
Graham Group (1). — W. S. Graham of Ukiah located a group of 17
claims on Big Red Mountain, the ridge which forms the boundary between
Mendocino and Lake Counties, 11 miles southeast of Ukiah. The moun-
tain is 4,000 to 4,200 feet in altitude, and stands 3,000 feet above the val-
ley to the west. Access to the deposits is by 4 miles of very steep dirt
road to Lost Valley from the county graveled road and 2 miles of trail
from Lost Valley. The deposits are distributed over a distance of about
half a mile along the high part of the ridge, near the center of T. 14 N.,
R. 11 W.
In 1918 three of the claims were leased by the Noble Electric Steel
Company, who mined a few tons of high-grade ore and about 75 tons of
low-grade ore. The high-grade ore was later shipped by H. B. Chase
Shipments of chromite from ilendocino County mines, 1918-42 (in long tons)
Mine or shipper
• Source of ore unknown.
18 CHROMITE DEPOSITS COAST RANGES [Bull. 134 Pt. II
of San Francisco. The claims had been allowed to lapse after World
War I, and in 1941 were held bj^ Edward George of Ukiah.
The deposits consist principally of thin layers and small lenses of
massive and disseminated chromite in dunite that is essentially barren.
Many of the layers of ore average 30 to 50 percent CroOs, but they are so
thin and intermixed with barren dunite that the minable rock would
exceed 20 percent CroOg in very few places. The largest of tlie high-
grade ore bodies jdelded about 5 tons of ore. Davis and Woodford
emphasized the fact that, although high-grade float was abundant in
places, the individual pieces were small and obviously were derived from
thin laj^ers. The deposits, therefore, would have to be worked by bulk
mining and milling methods.
The principal body of low-grade ore, according to Davis and Wood-
ford, is near the north end of the high part of the mountain, just east of
the divide. There the streaks and lenses of chromite strike north and
are nearly vertical ; they were exposed in pits and cuts over a distance of
300 feet. The chromite-bearing zone was described as at least 25 feet
wide, and in places outcrops indicated a width of 50 feet, although expos-
ures were not continuous across the entire width. A vertical depth of
50 feet of ore was indicated by exposures in a gulch below some open
pits. Davis and Woodford estimated a possible reserve of 10,000 to
30,000 tons of ore containing about 10 percent CroOs.
About 35 tons of ore averaging 40 percent Cr203 was dug from sev-
eral trenches near the top of the mountain, on the old Summit claim.
Near the south end of this claim, and about 200 feet below the crest of
the mountain, a tunnel was driven about 30 feet along the strike of an
ore body in which the layers strike N. 20° E. and dip 35° E. Wells
stated that this ore body is about 15 feet thick, and estimated the reserve
at about 500 tons of ore containing 5 to 10 percent CroOa.
When Wells visited the claims in 1941 most of the workings were
caved and very little ore could be seen. He mentioned a few nodules in
layers near the portal of the tunnel, which had caved in. (Wells, P. G.,
G. S. 41 ; Bradley W. W. 18, p. 154 ; Caldwell, F. B. 18 ; Davis and Wood-
ford, in Louderback, G. D. 18.)
Guthrie Group (2). — In 1918 more than 100 claims had been filed on
Big Red Mountain, in sees. 18, 19, 20, 29, 30, 31, and 32, T. 24 N., R. 16 W.,
northwest of Cummings. The claims extended more than a mile along
the crest of the ridge, at altitudes of 4500 to 4700 feet. In 1941 the
claims were reached bj^ steep county road from U. S. Highway 199 and
41/4 miles of road that could be negotiated only with an extra-low gear.
The deposits are 37 miles bj' road from Longvale, a station on the North-
western Pacific Railroad.
The claims are named for Alex Guthrie, who with Frank Asbill held
47 of the original claims on the mountain. These claims were leased
in 1918 to the Moreland Motor Truck Company which packed the ore out
to the road on mules. The total cost of transportation to Longvale was
about $30 a ton.
The summit of the mountain appears to be covered with a lateritic
soil in which chromite has been concentrated by weathering; in places
the soil is said to be 15 feet deep. There were few chromite outcrops,
but most of the ore was found by digging or hand-auger holes below
Chap. 1] NORTHERN COAST RANGES 19
accumulations of float. Much of the surficial ore was very friable, aud
some of it was very ]iip;h grade as a result of leaching of the serpentine
gangue. The ore that was sliipped came from 10 or more lenses which
ranged from N. 35° W. to N. 15° E. in strike, and dipped 50° to 65° NE
or E. The largest deposit is believed to have jaelded about 100 tons.
When Wells examined the deposits in 1941 little ore could be seen.
A few streaks of chromite were seen in dunite in a pit, about 100 feet
long, on the Blitty claim, but widespread saxonite float indicated that the
ore-bearing zone was probably 15 feet or less in width. Some streaks
and nodules of chromite were seen on the Marie, Surprise, and Last
Chance claims. (Wells, F. G., G. S. 41; Bradley, W. AV. 18, p. 152;
Davis and Woodford in Louderback, G. D. 18 ; Caldwell, F. B. 18.)
Liftle Red Mountain (Dunn) Deposits (3). — The Little Red Moun-
tain claims are in sec. C^, T. 23 X., R, 16 W., about 3 miles from U. S.
Highway 101. The claims were originally filed by E. A. and W. K.
Dunn, C. H. Hawkins, and J. L. Kelley, and in 1941 were held by
Eva Dunn. The topograpliic conditions and the character of the
deposits are similar to those on the Guthrie claims. In a trench near the
northwest corner of sec. 6, Wells saw a lens of coarse-grained massive
chromite about 2 feet wide that strikes N. 30° W. and dips 45° NE.,
and is said to have assayed 52 percent CroO-!. About half a ton of ore
was on the dump. High-grade dis,seminated ore in which some nodules
were noted was exposed in another trench, but the exposures were not
(rood enouch to justify an estimate of tonnage. (Wells, F. G., G. S. 41 ;
Davis and Woodford "in Louderback, G. D. 18; Caldwell, F. B. 18.)
Lloyd Prospect (4). — Arthur D. Lloyd of Longvale told Woodford
and Davis about chromite float in sec. 35, T. 23 N., R. 15 W., 6 miles by
trail from Nashmead, on the Northwestern Pacific Railroad. Appar-
ently the deposit has never been developed. (Woodford and Davis, in
Louderback, G. D. 18.)
Moore Prospect (5). — 0. B. Moore of TTkiah is said to have mined
15 to 20 tons of high-grade ore from a deposit in see. 24, T. 15 N., R.
13 W., IJ miles west of Ukiah. The deposit was mined out. (Wood-
ford and Davis, in Louderback, G. D. 18.)
Shields Prospect (6).-~W. E. Shields of Covelo collected about 30
tons of high-orade float ore in sec. 11, T. 23 N., R. 11 W., 25 miles north-
ea.st of Dos Rios. No ore was found in place, and because of the inacces-
sibilitv of the deposits none of the ore was shipped. (Bradley, W. W.
Unnamed Prospect (7). — Taliaferro described chromite occurring
as blocks up to 6 or 8 inches in diameter in a slide made up largely
of serpentine fragments, on the west bank of the middle fork of the
Eel River opposite the locality known as the Hell Hole. This deposit
appears to be in the WtI sec. 1, T. 23 N., R. 11 W., opposite Hell Hole
Canyon. A few hundred pounds of ore had been piled in one place,
but Taliaferro indicated that the source of the ore probably would be
difficult to find because of the extensive slides.
The deposit may be the same one described in 1918 as the Shields
prospect, for the locations and descriptions of the two deposits are very
similar. (Taliaferro, N. L., in Louderback, G. D. 18.)
CHROMITE DEPOSITS COAST RANGES [BuU. 134 Pt. II
Shipmenta of chromite from 2fapa County mines, 1916-41 (in long tons)
Mine or shipper
Bradley and Eckstrom*._
1937-39: 64,20, 20
G. W. Elder* .
H. W. Mullaly*
Sun Slope (T. L. Neil)*
* Source of ore or location of deposit unknown.
Chromite deposits are distributed over the northeastern part of
Napa Countj' in a number of serpentine masses. Half of the deposits
are concentrated in the northeastern corner of the county between Putah
and Eticuera Creeks, in the southern end of a large serpentine mass
which extends northward about 15 miles into eastern Lake County.
The other deposits are much more widely scattered. For convenience,
the deposits between Putah and Eticuera Creeks are described together
as the Northern deposits and the others as the Southern deposits.
Black Eaivk Claim (1). — The Black Hawk claim was apparently
located by T. L. Neil in 1916, in sec. 23, T. 11 N., R. 5 W., about 2 miles
west of the Moore mine (59). Caldwell did not visit the claim, for he
was told that little ore remained after 126 tons had been mined and
shipped in 1916 and 1917. (Caldwell, F. B. 18.)
Cigarette Mine (2) \94].- — The Cigarette mine is in sec. 5, T. 10
N., R. 4 W., 6 miles from Monticello. In 1918 it was covered by a claim
located by "W. M. Noel of Monticello. Davis reported that the mine had
produced over 250 tons of high-grade ore, which was sledded a mile,
hauled 4 miles over a bad road by light trucks, then hauled 30 miles in
heavy trucks to "Winters. Onlj^ small patches of chromite were left
on tile walls of the cuts in July 1918. (Bradley, W. W. 18, p. 157;
Davis, E. F., in Louderback G. D. 18.)
Crystal Creek Claim (3). — The Crystal Creek claim, which was
abandoned in 1918, was on a deposit in the SW^ see. 12, T. 10 N., R.
5 W., on a fork of Cement Creek. Forty tons of ore was mined and
shipped from an open cut about 50 feet above the creek. The ore body
was about 10 feet square by 4 feet thick and dipped about 10° S. in
sheared serpentine. A few 2- to 3-ineh stringers were left. (Davis,
E. F., in Louderback, G. D. 18.)
Dollerkyde Claim ('4 j.— High-grade chromite float was found on a
claim held in 1918 by R. A. Dollerhyde, in sec. 6, T. 10 N., R. 4 W. Trench-
ing failed to uncover ore in place, and after some ore was shipped the
claim was abandoned. (Davis, E. F., in Louderback, G. D. 18.)
Chap. 1] NORTHERN COAST RANGES 21
Ferris Claim (5).— The Ferris claim, in sec. 36, T. 11 N., R. 5 W.,
was owned by Georjie Graves and leased to the Sawyer Tanninp Com-
pany in 1918 and 1919. Eight tons of ore was shipped in 1918 from
an 8-foot open cut and 10-foot shaft. When Caldwell visited the mine
a chromite lens 6 to IS inches wide was exposed over a length of 10 feet.
This body and small nearby lenses were said to strike about north and
dip steeply either east or west. (Caldwell, F. B. 18.)
Graves Mine (6) . — The Graves chrome mine is in the NE^ sec.
36, T. 11 N., R. 5 "W., at an elevation of about 1120 feet, on a gentle grass-
covered hillside. In 1942 the deposit was owned by "W. B. Shepherd of
Monticello and leased to the Anglo-American Mining Company of Clovis.
George Graves owned the mine in 1918 and leased it three times, the last
time to the Sa^vA•er Tanning Compan.y after the others thought it was
mined out. From 1916 to 1918 about 410 tons of ore was shipped, 230
tons of it by the Sawj-er Tanning Company.
At one time in 1918 ore was exposed continuously along one side of
an open cut 50 feet long, iip to 30 feet wide, and 20 feet deep on the uphill
side. There were also several smaller cuts. The main ore body evidently
was about 50 feet in length, 20 feet in maximum width, and about 8 feet
in greatest thickness. The strike of the chromite lenses was about N. 80°
"W. ; they dipped at a low angle into the hill.
The old workings were badly caved in 1942, and only low-grade
disseminated ore could be seen in three of the pits. About 50 tons of
low-grade ore was stockpiled when Gros visited the mine, and reserves
of low-grade ore in place apparently were very small. (Gros, F., G. S.
42;Caldwell, F. B. 18.)
Grey Claim (7).— The Grey claim, held in 1942 by W. B. Shepherd
of Montieello and leased to the Anglo-American Mining Company of
Clovis, was owned and operated in 1918 by John Moore, of Montieello.
The claim is 14 miles from Calistoga, in sec. 13, T. 11 N., R. 5 W.
About 100 tons of chromite was shipped from this mine in 1918.
The ore was roughly divided into two grades: gray sandy ore mixed
with serpentine, and containing 30 to 38 percent CroO.-j ; and friable high-
grade chromite that contained 40 to 45 percent CroOa. Truck-load lots
sent to the Sawyer Tanning Company ranged from 29.2 to 44.5 percent
The ore was mined from an open cut 70 feet long, 6 to 10 feet wide,
and 20 feet deep, and a shaft sunk 8 feet below the floor of the cut near
the face. The chromite formed a number of closely packed lenses in a
space about 25 feet long, 3 to 6 feet wide, and 30 feet deep, in a north-
south vertical shear zone. In 1942 the cuts were badly caved, and no
ore could be seen in place. About 200 tons of ore of various grades was
stacked near the workings. (Gros, F., G. S. 42 ; Caldwell, F. B. 18.)
Eightower Claim (8). — "W. C. Hightower was said to have a claim
in sec. 12 or 13, T. 10 N., R. 5 "W., from which 5 or 6 tons of ore was mined.
(Caldwell, F. B. 18.)
Moore Mine (9) . — John Moore of Montieello owned several
chromite deposits in sees. 17, 18, and 19, T. 11 N., R. 4 W., which as a
group were knovm as the Moore mine or Moore claims. The largest
deposits were on the Marshall and Vanderbilt claims, and shipments of
about 450 tons were about evenly divided between the two claims. Part
of the ore was sold to the California Chrome Company and part to the
Sawyer Tanning Company.
22 CHROMITE DEPOSITS — COAST RANGES [BuU. 134 Pt. II
On the Marshall claim a vertical shear zone striking northeast was
explored over a distance of 1500 feet by three groups of open cuts, pits,
and trenches. At the main workings several open cuts, the largest of
which was 50 feet long and 25 feet deep at the face, were dug on 5 parallel
chromite lenses ranging up to 30 feet long and 1 to 3 feet wide. These
lenses were scattered over a width of about 50 feet in the shear zone.
One of the ore bodies had the form of a very irregular pipe that ranged
from 1 to 25 square feet in cross-sectional area and was mined to a depth
of 15 feet. A 3- by 4-foot lens was found 1000 feet southwest of the main
deposits, and two parallel ore bodies were found 500 feet farther on.
Davis said that the ore averaged about 40 percent CroOs, and Caldwell
indicated that it ranged in grade from 35 to 40 percent Cr^Oa.
The workings on the Vanderbilt claim revealed chromite in a curved
zone about 75 feet long, swinging in strike from N. 45° W. to N. 60° E.
The lenses of chromite lay parallel, and some of them cut across the trend
of the ore-bearing zone. The descriptions by Caldwell and Davis are
somewhat obscure, but Caldwell 's mention of a shaft 10 feet square and
40 feet deep suggests that one of the ore bodies mined after Davis' visit
was pipe-like in form. Caldwell describes the ore as black, speckled, and
homogeneous, and rann-ing from 41 to 46 percent in Cr-^Os content.
(Caldwell, F. B. 18; Davis, E. F., in Louderback, G. D. 18.)
Mullaly Mine (10). — About 85 tons of ore assaying 43 to 50 percent
CroOg was shipped to the Saw^-er Tanning Companv from a deposit in
sec. 18, T. 11 N., R. 4 W., by H. "W. Mullaly of Monticello. The deposit
was near the road to the Moore mine (9) and about 28 miles from Monti-
The chromite occurred as lenses of various sizes in a shear zone
trending northeast and dipping 45° N"W. In September 1918, the work-
ings consisted of a cut 70 feet long and 20 feet deep at one end, and .smaller
cuts at irregular intervals over a distance of 200 feet along the shear
zone. The largest ore body appears to have been about 20 feet long and
I to 3 feet wide. (Caldwell, F. B. 18; Davis, E. F., in Louderback,
G. D. 18.)
Nevada Claim (11). — The Nevada claim was one of a group of three,
the others being the Rockerfeller and St. Gabriel, located in 1918 by
George Vanderbilt of Monticello. The Nevada claim was in sec. 32, T.
II N., R. 4 W.
Trenches at places where high-grade float was found on the Nevada
and Rockerfeller claims failed to find ore in place, and a trench on the
St. Gabriel claim revealed a half-ton deposit of disseminated ore estimated
to contain 38 percent CroOs. A tunnel, 75 feet down the hill from this
ore body, was abandoned after being driven a few feet. There is no
record of ore shipped from these claims. (Davis, E. F., in Louderback,
G. D. 18.)
Turner Mine (14). — The Turner mine is in sec. 1, T. 10 N., R. 5 W.,
and was worked in 1918 by Clifford Turner. Caldwell said that 40 tons
of ore averaging about 40 percent CroOs was shipped to the Sam-er Tan-
ning Company before the end of August 1918.
The mine consisted of a small open cut and a 5- by 7- foot shaft 30
feet deep sunk on an ore body in a shear zone striking northwest and
dipping 35° SW. The ore body appears to have been tabular, for it is
described as 6 to 10 feet long by a few inches to 4 feet wide on the surface.
and 10 feet long by 1 to 3 feet thick at the bottom of the shaft.. Some of
Chap. 1] NORTHERN COAST RANGES 25
the ore was clean and homoo:eneous, but most of it was said to consist of
nodules in yellowish-green serpentine. (Caldwell, F. B. 18.)
Unnamed Prospects (15, 16, 17). — A small prospect (15) was seen
in a shear zone striking; N. 50° E. and dipping 75° NW. in serpentine in
the SW 14 sec. 12, T. 11 N., R. 5 W.
Other prospects (16, 17), consisting of several small pits and a 20-
foot adit that was badly caved were found in the SE V^ sec. 18, and the
SW \ sec. 17, T. 11 N., R. 4 W. during mapping of mercury deposits.
A lens of chromite about 10 feet long, 7 feet wide, and about 5 feet thick
was seen in sec. 18 in a shear zone which strikes N. 55° E. and dips 50°
SE. The pits in see. 17 revealed only a 12-iiich lens of low-grade ore.
(Averitt, P., G. S. 41.)
Astute Mine ('iSj.— The Astute mine, in sec. 32, T. 10 N., R. 5 W.,
was held by Young Adams and W. D. Hays of Middletown. The mine
is 19 miles from St. Helena, near an old lime kiln in Butts Canyon.
Caldwell described the deposit as a kidney-shaped mass exposed over
a length of 30 feet and a few inches to 6 feet or more in width, in soft yel-
low sandy serpentine. The strike of the ore body w£is north and it dipped
at a low angle. Davis indicated that the ore ranged in grade from about
38 to 50 percent Cr^Os and Caldwell said it disintegrated into coarse
crystals. The boundaries between high- and low-grade ore were
extremelj- irregular. The mine is said to have shipped a little more than
200 tons to the Sawver Tanning Company. (Davis, E. F., in Louder-
back, G. D. 18; Caldwell, F. B. 18.)
Chrome Center Claim (19). — A "fairly high grade body of mas-
sive gray chromite" was found on the Chrome Center claim in sec. 36,
T. 10 X., R. 5 W., by R. W. Wallace of Pope Valley. The ore body was
developed hj a 20-foot open cut showing 5 feet of ore in places. A small
exposure of chromite 75 yards east of the main deposit had not been
explored at the time the mine was visited in 1918. There are no records
of shipments from this mine, although about 30 tons had been mined.
(Bradley, W. W. IS, p. 156.)
Elder Claim (20). — About 20 tons of ore averaging 45 percent
Cr203 was shipped from a deposit north of the house on the G. W. Tarry
homestead, in sec. 31, T. 10 N., R. 4 W. The deposit was completely
mined out. (Davis, E. F., in Louderback, G. D. 18.)
Fourth of July Claim (21). — Float ore only was found on the
Fourth of July claim in the N4 sec. 18, T. 10 N., R. 5 W., three-quarters
of a mile fi'om the Butts Canyon road and about 23 miles from St.
Helena. The deposit was worked by Frank Rhoda of Pope Valley.
The chromite was found as boulders in red soil on serpentine.
Fifteen tons of ore had been mined from an open cut 10 by 20 feet in
area and 3i feet deep, and pieces of ore were visible in the walls. The
cut apparently was not dug to bed rock or to the upper limit of float on
the hillside. Although the ore appeared to be massive, it was said to
assay only 42.2 percent Cr203. A patch of angular float in which ser-
pentine adhered to the fragments, several hundred feet below the open
cut, was regarded by Davis as evidence of another deposit, but appar-
ently it was not explored. (Da-vis, E. F., in Louderback, G. D. 18.)
24 CHROMITE DEPOSITS COAST RANGES [BuU. 134 Pt. II
Glad I Found Ton No. 2 Claim (22).— The Glad I Found You No. 2
claim was located bv "W. D. Hays and Young: Adams of Middletown.
It was in sec. 19, T." 10 N., 11. 5"w., within 100 feet of the road from
St. Helena via Butts Canyon and Howel Mountain. About 200 pounds
of float estimated to contain 45 to 48 percent Cr203 was found at two
places. (Davis, E. F., in Louderback, G. D. 18.)
Graves Ranch Deposit (23)  .—Hamilton stated in 1920 that
the Graves Ranch mine produced 900 tons of ore which was sold to
the Sawj-er Tannin? Company, and he said the mine was in see. 11, T.
9 N., R. 4 W. Since no other investigators have reported an important
mine in this vicinitv it seems likely that Hamilton was referrin;; to the
Graves chrome mine (6) . (Boalich, E. S. 21, p. 158 ; Averill, C. V.
29, p. 216.)
Nichelini Mine (24). — The Nichelini mine, in sees. 33 and 34, T.
8 N., R. 4 W., was worked in 1918 by A. Nichelini of Chiles. The
ehromite was found in a series of lenses alined in a northeast direction
with their lonjr axes pitching 25° to 30° NE. The principal ore body
was said to have yielded aboi^t 2000 tons in the early days, when it
was mined out. Nichelini found several smaller lenses ransring from
5 to 40 tons each near the old cut. In June 1918 a tunnel was being
driven under the old workings, and only a few hundred pounds of ore
from old dumps was stacked for shipment. Da%ns indicated that 100
tons of ore averaging 45 percent CroOs and ranging up to 50 percent
Cr203 was shipped in 1918 from this deposit. (Davis, E. F., in Louder-
back, G. D. 18.)
Reeve Claims (25). — The Reeve claims consist of three claims on
public land and 40 acres of patented land owned by R. B. Reeve in
sees. 10 and 14, T. 8 N., R, 5 W., 5i miles northea^st of St. Helena.
The deposits are widely scattered over a low hill that has smooth mod-
erately steep slopes.
The ore occurs as scattered lenses and pods of massive and high-
grade disseminated, medium-grained ehromite. The ore bodies average
about a foot thick and 4 to 5 feet long; the largest found was about
3 feet thick and j-ielded about 2| tons of ore. Two pits, 8 by 2 by 2
feet and 25 by 2 by 1 to 4 feet, respectively, had been dug on the patented
land and 3 pits, the larirest of which was 30 by 2 by 1 to 8 feet, had been
dug on claim No. 1. The ore is said to assav about 52 percent CroOs.
(Cater, F. W. Jr., G. S. 43.)
Claims in Vicinity of Samuel Springs (26-30). — Fifteen claims
were staked during World War I on ehromite deposits in a mass of
serpentine which forms the divide between Pope Valley and Trout
Creek, in the vicinity of Samuel Springs. The serpentine extends
southwest from sec. 20 through the southwestern part of T. 9 N., R.
4 W., at least as far as see. 10, T. 8 N., R. 4 "W. The claims were located
by 8 residents of Monticello, individually or in partnership : E. V.
McGinnis had interests in 8 claims, C. D. Sweitzer and R. S. Little
were partners in 7 claims each ; A. R. Asbill, Allen Lewis, and "W. D.
"^T^cKenzie were part owners of 2 claims each ; and E. A. Boyington and
W. C. Cook each had part of one claim. The names of the claims and
their locations are shown in the following table.
NORTHERN COAST RANGES
Claims in vicinity of Samuel Springs
Buzzard _ _ _ - _ .
Hampton . _
Lost Horse. ..
Very little work had been done on the claims when Caldwell and
Davis visited them in 19] 8, and no oi"e is kno^vn to have been shipped.
Trenches on the Blue Jay, Buzzard, Buzzard No. 2, and Trout Creek
claims revealed small stringers a)id lenses of massive chromite a few
inches thick. Several shallow trenches which did not reach bedrock
were dug on the Cedar Rough, Eagle, Hampton, and Lost Horse claims,
and a quarter to half a ton of iioat was collected on each of the Hono-
lulu Lady, Mistake, and Viola claims. Several patches of float on the
Dottie D., Lizzie P., and Meadow claims apparently were left untouched.
(Davis, E. F., in Louderback, G. D. IS; CaldweU, F. B. 18.)
SuUingcr Claim (31). — About a quarter of a ton of chromite was
mined from the Sullinger claim before it was abandoned in 1918 by
W. Kilpatrick of Oakville. The deposit is in sec. 2, T. 7 N., R. 5 "W.,
5 miles northeast of Rutherford. A lens of high-grade ore 3 feet long
and 6 to 8 inches wide was found in one pit, and the extension of this
lens or another lens like it was exposed in another pit 6 feet away.
(Bradley, W. W. 18, p. 157.)
Tarr%j Claim (32).— G. E. Tarry, of Etna Springs, in 1918 shipped
45 tons of ore to the Sa\\yer Tanning Company from deposits in the
XEi sec. 31. T. 10 N., R. 5 E. The main ore body was about 50 feet
lunar and 1 to 5 feet wide, and was mined to a depth of about 20 feet.
Chromite was exposed in a small cut 100 feet northwest of the main pit,
and float in several places indicated other ore bodies. (Davis, E. P., in
Louderback, G. D. 18; Caldwell, F. B. 18.)
Unnamed Prospects (33, 34). — Low-grade disseminated ore was
found by G. E. Tarry in sec. 5, T. 9 N., R. 5 W., half a mile from the
Butts Canyon road. Although a few small lenses of ore were said to
contain as much as 40 percent Cr^jOs, most of them were estimated to
average 10 to 15 percent. The small size and low grade of the deposits
apparently precluded profitable mining.
G. B. Powers of Rutherford told Davis of a chromite deposit in
sec. 12, T. 7 N., R. 4 W., but as very little mining had been done, and
no ore had been mined, Davis did not visit the deposit. (Davis, E. F.,
in Louderback, G. D. 18.)
CHROMITE DEPOSITS COAST RANGES [Bull. 134 — Pt. II
Although relatively few ehromite deposits have been found in
Sonoma Countj-, they have a much larger per capita production than the
deposits in Lake and Napa Counties, and contain larger reserves. Very
little ore has been shipped from the county since 1918 ; the main produc-
tion came before 1890.
Barnes Mine (1) . — The Barnes mine was first worked by
Edward Barnes before 1884, and since then has been known by many
names. Barnes' mining apparently was limited to surface work, and
underground mining was started in 1896 bj' unknown persons. From
1916 to 1918 the Wanderer Jlining Company, of San Francisco, worked
three parcels of land in the vicinity belonging respeetivel}- to J. Ferrari,
V. and A. Ardoin, and someone named McMahon, all of Cloverdale.
These properties include land in sees. 30, 31, and 32, T. 11 N., K. 10 W.,
but most of the workings are in see. 32. The main mine is about 4 miles
southwest of Cloverdale.
The available information indicates that the ore was collected from
surface float or alluvial deposits, and that very little of it was mined from
ore in place. A large part of the ore apparently was mined from river
deposits in which pieces of ehromite from an inch to a foot across were
abundant, and boulders ranging up to 12 tons were occasionally found.
The ore was said to be especially abundant in the lowermost beds, which
rested on serpentine.
In 1918 the Wanderer Mining Company sank an inclined shaft 15
feet below the creek bed and 30 feet below the general ground level, on
the Ardoin land, and drove a number of irregular drifts which inter-
sected old workings. The gravel was soft enough to dig by hand, yet
firm enough to stand well without timbering ; the waste was used to divert
the creek. A few small streaks of ehromite were found in bedrock in
pits sunk along the creek on the Ferrari tract, but they were too small to
mine at a profit. Several tons of float were collected and one carload of
ore was shipped in 1918. (Bradlev, W. W. 18, p. 203 ; Hanks, H. G. 84,
p. 137 ; Crawford, J. J. 96, p. 50 ; Davis, E. F., in Louderback, G. D. 18 ;
CaldweU, F. B. 18.)
Gaver Prospect (2). — Chromite float was found in several places,
and small lode stringers were exposed in pits on land belonging to A. P.
Gaver, in sec. 27, T. 7 N., R. 10 W. Caldwell saw about half a ton of ore
in place. (Caldwell, F. B. 18.)
Laton Mine (3). — The Laton mine is owned by A. J. Laton, son of
A. H. Laton, who worked the mine in 1918, and in 1942 and 1943 was
operated by A. S. and Roy Laton. B. M. Bowman is believed to have
Shipments of chromite from Sonoma County mines, 1916-18 (in long tons)
Mine or shipper
B. M. Bowman*
S. M Thomas*
• Source of ore unknomL
Chap. 1] NORTHERN COAST RANGES 27
worked the mine in 1916 and 1917. The deposits are covered b.y 3 claims,
the Slats and Rattlesnake, which are in the NE^SEi see. 13, T. 9 N., R 12
W., and the Yellow Streak, which is in the SW^SW^ sec. 18, T. 9 N., R. 11
W. The mine is 10.3 miles by road from Cazadero, divided as follows :
6 miles of Forest Service dirt road, 3.2 miles of one-way road, and 1.3
miles of bulldozer road. All the claims are on steep slopes; the Rattle-
snake and Slats are 100 to 300 feet above Austin Creek, and the Yellow
Streak is on a small tributaiy. Austin Creek is a permanent stream
which would supply plenty of water for a mill.
Two to 4 carloads of high-grade ore mined principally on the Yellow
Streak claim are said to have been shipped in 1918. Assays by the Smith-
Emery Laboratories indicate that the last carload contained slightly more
than 51 percent Cr^Oa.
A large number of small high-grade lenses were exposed on the Yel-
low Streak claim, but the largest of them was estimated to contain less
than 15 tons, and the main reserves consist of low-grade disseminated
ore on the other claims. There are three lenses on the Slats claim, 125
by 10 by 5 feet, 70 by 15 by 2 feet, and 50 by 10 by 5 feet, respectivelJ^
They strike north or slightly west of north and appear to dip about 20°
E. They have frozen contacts and grade into the surrounding serpentin-
ized peridotite except where bounded by slickensided joints which strike
about north and dip as much as 35° E. The movement on the joints has
apparently been small. A body of ore estimated to contain about 10
percent by volume of chromite was exposed over a length of 35 feet and
width of 10 feet in the only pit on the Rattlesnake claim. This body
strikes N. 22° "W. and dips about 65° NE., nearly parallel to the dominant
The probable reserves were estimated as somewhat more than a
thousand tons, but if the maximum depth of each lens down the dip is
assumed to be equal to half the outcrop length, the reserves would be
between 10,000 and 15,000 tons. The ore is believed to average 10 to 15
percent CroOs and Mr. Laton planned to sweeten the ore from the low-
grade deposits with higher-grade ore from the Yellow Streak claim. A
small mill began operation early in 1944, and during the year produced
almost 50 long tons of concentrates containing about 48 percent CroOs,
and having a Cr/Fe ratio of 2.6. (Wells, F. G., G. S. 43 ; Gros, F., G. S.
42; Bradlev, W. W. 18, p. 203; 15, p. 319; Boalich, E. S. 21, p. 248;
Laizure, C. McK. 26, p. 333.)
Madeira Claim (4). — In 1916 George Madeira of Healdsburg mined
about 100 tons of chromite from several small lenses on a claim in see.
31, T. 9 N., R. 10 "W., about 8 miles north of Guerneville. The ore was
said to contain 34 percent Cr20,i, and there is no record that it was
shipped. (Bradley, W. W. 18, p. 201.)
Bed Hill Claim (5). — The Red Hill claim, which was owned in 1942
by E. A. Truitt of Healdsburg, is in sees. 15 and 22, T. 11 N., R. 9 W., at an
elevation of about 2400 feet on the north end of a ridge. In 1918 the
claim was leased by G. "W. Elder of St. Helena, who mined 150 to 200
tons of ore.
When Gros visited the deposit in 1942 the workings were badly
caved, and there was little evidence of recent work. The workings
included a cut about 150 feet long, 10 feet wide and 8 feet deep ; a partly
caved 15-foot drift at one end of the cut ; and two small pits. Chromite
could be seen only in the two small pits, in sheared serpentine and white
28 CHROMITE DEPOSI'TS — COAST RANGES [Bull. 134 Pt. II
clay gouge. Scattered veinlets of cinnabar were seen in white silicified
serpentine east of the larger cut.
The ore mined in 1918 apparentl.v occurred as nearly horizontal
high-grade lenses distributed over an area 100 feet long and 6 feet wide
in the large cut. The high-grade ore was said to be more or less sur-
rounded by disseminated ore or a mixture of chromite fragments and
sheared serpentine; narrow stringers were common. The high-grade
ore was soft and friable, and the low-grade ore was described as sandy.
(Gros, F., G. S. 42 ; Caldwell, F. B. 18 ; Davis, E. F., in Louderback, 6. D.
18 ; Boalich, E. S. 21, p. 248.)
Rough Crossing Claim (6) .—The Rough Crossing claim is in sec. 21,
T. 9 N., R. 11 "W., on patented land which in 1918 belonged to the Eakles
Brothers and was leased to K. K. Ash of Healdsburg. It was near the
narrow-gage railroad of the Sonoma Magnesite Company. Caldwell
indicates that a little shipping-grade ore had been mined from narrow
stringers in an extensive deposit near the railroad. The shipping-grade
ore was estimated to contain 40 percent Cr203, but the deposit as a whole
was believed to average 6 percent CroOs or less. A small deposit about a
mile to the southeast yielded about 12 tons of ore containing about 40
percent Cr203, but none of it was shipped. (Caldwell, P. B. 18.)
Shanks and Copps Claim (7). — Shanks and Copps, of San Fran-
cisco, in 1918 leased claims in sec. 13, T. 10 N., R. 11 W., 9 miles west of
Geyserville. Much float was found on the ridge north of Skaggs Springs
and about 20 tons of good ore was mined from several small deposits. As
the ore was piled at the roadside when the mine was visited in 1918, it
probably was hauled away and shipped, although there is no official
record of the shipment. (Bradley, W. W. 18, p. 203 ; Laizure, C. McK.
26, p. 333.)
Sonoma Chrome, Inc. (8). — Bentley Neuman of Santa Clara leased
2000 acres of the Meeker Ranch in 1942 under the name of Sonoma
Chrome, Inc., and obtained a loan from the Reconstruction Finance Cor-
poration to clean out the old chromite workings and develop low-grade
ore. The mine, then known as the Meeker, was leased in 1918 by S. H.
Dolbear, who shipped 644 long tons of ore containing 39 to 42 percent
CroOs. The deposits are in sees. 15, 16, and 17, T. 7 N., R. 10 W., on
rounded grass-covered hills, and are 17 miles by paved highway from
The chromite deposits are aliued in three main ore-bearing zones
which strike about N. 40° W., parallel to the schistosity in the .serpentine
country I'ock. In 1942 low-grade ore was exposed to a depth of 4 feet
over two areas about 100 feet by 50 feet each, about three-quarters of a
mile apart. The mining in 1918 was limited mainly to a line of high-
grade deposits half a mile southwest of the low-grade deposits. The
principal working was an open cut 125 feet long by 15 to 20 feet deep,
in which a 55-foot shaft was sunk at the lower end. From the shaft a
drift is said to have been driven at least 40 feet in ore along the strike
back under the cut, and Caldwell indicates that the ore body was a
single vertical lens which extended more than 60 feet below the surface.
Most of the old pits are less than 10 feet deep, and the other deposits
seem to have been small.
The high-grade ore is dense and massive, and is said to range from
42 to 51 percent CroOa, with a Cr/Fe ratio of about 3 :1. The low-grade
Chap. 1 J NORTHERN COAST RANGES 29
deposits are estimated to contain 15 to 20 percent CroOs, and the reserves
appear to be less than 5000 long tons. (Gros, P., G. S. 42; Bradley,
W. W. IS, p. 201 ; Laizure, C. McK 26, p. 33:1 ; Caldwell, F. B. 18.)
Warner and Clark Claim (9). — Paul Warner of Pine Plat and
Charles Clark of Calistoga located claims in sec. 10, T. 10 N., R. 8 W.,
near Pine Plat. Blocks of chromite weighing up to 50 or 60 pounds
were scattered in the north half of the section, and several small lenses
of high-grade ore were found in place. The largest deposit yielded
about a ton, and although 5 tons was collected, no ore was shipped.
(Davis, E. P., in Louderback, G. D. 18.)
Welch Prospect (10).— The Welch prospect is in sec. 22, T. 9 N.,
R. 11 W., near the Rough Crossing claim, and about a mile from the old
Sonoma Magnesite Company railroad. It is on land which in 1918 was
owned by Charles Welch, of Guerneville. An open cut revealed an
irregular ore body about 50 feet long and 2 feet thick, which trended
northwest and appeared to stand vertical. Caldwell estimated the
reserves at 20 tons averaging 42 to 45 percent CrgOs, but the deposit was
not worked because the price asked by the owner was too high. (Cald-
weU, P. B. 18.)
Alphabetical List of Mines and Prospects
In the accompanying table the mines and prospects are listed alpha-
betically bj' counties and numbered as in figure 1. The ownership of
the claims is given as of the date of the last report on the deposit and,
therefore, in very few instances indicates the owner in 1944. The
deposits are divided by production into four classes: A, deposits or
properties from which at least 1000 tons of ore has been shipped; B,
deposits from which 150 to 1000 tons of ore has been shipped ; C, deposits
from which small amounts of ore, but not more than 150 tons, have been
shipped; and D, deposits from which no ore has been shipped, or whose
location is uncertain.
CHROMITE DEPOSITS COAST RANGES [BuU. 134 Pt. II
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NORTHERN COAST RANGES
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Aubury, Lewis E.
06 The stnicturnl and industrinl mnterinls of California: California Min. Bur.
Bull. ;!8. 412 pp., 1906. (Chromitc, pp. 266-272, 362-363.)
Averill, Charles Volney
29 San Francisco field division — Napa County : California l)iv. Mines and
MininfT Rept. 25, pp. 213-242, 1929 Lake County : pp. 337-,365, 1929 Men-
docino County : pp. 456-467, 1929. (Chromite, pp. 216, 340-341, 462.)
45 Quicksilver deposits of the Knoxville district, Napa, Yolo, and Lake Coun-
ties, California : California Jour. Mines and Geology, vol. 41, pp. 65-89, 2 figs., pis.
6-14, 1945. (General geology, northern Coast Ranges.)
Boalich, E. S.
21 San Francisco field division : California Min. Bur. Rept. 17, pp. 5-261, 1921.
(Chromite: Napa County, p. 158; Sonoma County, p. 248.)
Bradley, Walter W.
15 The counties of Colusa, Glenn, Lake, Marin, Napa, Solano, Sonoma, Yolo :
California Min. Bur. Rept. 14, pp. 173-370, 1915. (Chromite : Colusa County, p. 178 ;
Glenn County, p. 198; Lake County, p. 204; Marin County, pp. 247, 248; Napa
County, p. 268 ; Solano County, p. 307 ; Sonoma County, p. 319.)
18 (Huguenin, E., Logan, C. A., Tucker, W. B., and Waring, C. A.) Man-
ganese and chromium in California : California Min. Bur. Bull. 76, 284 pp., 1918.
(Chromium, pp. 101-228.)
Caldwell, F. B.
18 Reports on chrome localities in California ; made for U. S. Bureau of
Mines as part of Cooperative War Minerals Investigation in California, in coopera-
tion with TJ. S. Geological Survey and California State Council of Defense. Unpub-
lished ; on file at offices of California Division of Mines. 1918.
Crawford, J. J-
96 Thirteenth report (third biennial) of the State Mineralogist for the two
years ending September 15, 1896: California Min. Bur. Rept. 13, 726 pp., 1896.
(Chromic iron, pp. 48-50.)
Dlller, Joseph Silas
19 Chromite : Mineral Resources U. S., 1916, pt. 1, pp. 21-37, California pp.
27-34, 1919 1919, pt. 1, pp. 87-91, California pp. 87-89, 1921.
20 Chromite in 1018 : Mineral Resources U. S., 1918, pt. 1, pp. 657-725, Cali-
fornia pp. 660-669, 1920.
Hanks, Henry G.
84 Catalogue and description of the minerals of California as far as known,
with special reference to those having an economic value : California Min. Bur. Rept. 4,
pp. 61-397, 1884. (Chromite, pp. 126-139.)
Jenkins, Olaf P.
43 [Manganese in California] Preface: California Div. Mines Bull. 125, pp.
9-12, 1943. (Description of Cooperative War Minerals Investigation between the
U. S. Bureau of Mines, U. S. Geological Survey, and California State Council of
Laizure, C. McK.
26 Sonoma County : California Min. Bur. Rept. 22, pp. 327-365, 1926. (Chro-
mite, pp. 332.333.1
Louderback, George D.
18 Chromite investigation ; descriptions of individual deposits for the Cali-
fornia State Council for Defense in 1917-19. Includes reports by various authois.
Unpublished; copies on file at the U. S. Bureau of Mines, Washington, D. C, and at
the offices of the California State Division of Mines, 1918.
38 CHROMITE DEPOSITS COAST RANGES [BuU. 134 Pt. II |
Rynearson, Garn A.
44 (and Wells, F. G.) Geology of the Grey Eagle and some nearby chro- '
mite deposits in Glenn County, California : U. S. Geol. Surrey Bull. 945A, 22 pp., I
4 figs., 6 pis., 1944.
Taliaferro, N. L.
41 Geologic history and structure of the central Coast Ranges of California :
California Div. Mines Bull. 118, pp. 119-163, 1941.
18 Reports on chrome localities in California ; made for U. S. Bureau of Minesl
as part of Cooperative War Minerals Investigation in California, in cooperation with
U. S. Geological Survey and California State Council of Defense. Unpublished; on"
file at offices of California State Division of Mines. 1918.
Yates, Robert G.
46 (and Hilpert, L, S.) Quicksilver deposits of eastern Mayacmas district.
Lake and Napa Counties, California : California Jour. Mines and Geology, vol. 42,
pp. 231-286, pis. 34-48, 1946. (General geology, northern Coast Ranges.)
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