GEOLMY
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Sci.LiB.
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
GEOLOGY OF
SOUTHWESTERN
SANTA BARBARA COUNTY
CALIFORNIA
POINT ARGUELLO, LOMPOC, POINT CONCEPTIO!^,
LOS OLIVOS, AND GAVIOTA QUADRANGLES
BULLETIN 150
1950
DIVISION OF MINES
FERRY BUILDING, SAN FRANCISCO
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STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
GEOLOGY OF
SOUTHWESTERN
SANTA BARBARA COUNTY
CALIFORNIA
POINT ARGUELLO, LOMPOC POINT CONCEPTION,
LOS OLIVOS, AND GAVIOTA QUADRANGLES
BULLETIN 150
1950
DIVISION OF MINES
FERRY BUILDING, SAN FRANCISCO
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STATE OF CALIFORNIA
EARL WARREN, Governor
DEPARTMENT OF NATURAL RESOURCES
WARREN T. HANNUM. Director
DIVISION OF MINES
FERRY BUILDING, SAN FRANCISCO
OLAF P. JENKINS, Chief
3AN FRANCISCO
BULLETIN 150
JUNE 1950
GEOLOGY OF
SOUTHWESTERN
SANTA BARBARA COUNTY
CALIFORNIA
POINT ARGUELLO, LOMPOC, POINT CONCEPTION,
LOS OLIVOS, AND GAVIOTA QUADRANGLES
By
T. W DIBBLEE, JR.
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LETTER OF TRANSMITTAL
To His Excellency
The Honorable Earl Warren
Governor of the State of California
Sir:
I have the honor to transmit herewith Bulletin 150, Geology of
Southwestern Santa Barbara County, California, prepared under the
direction of Olaf P. Jenkins, Chief of the Division of Mines, Department
of Natural Kesources. The report covers an area topographically mapped
by the Federal Government in five 15-minute quadrangles comprising an
area of 700 square miles, namely : Point Arguello, Lompoc, Point Con-
ception, Los Olivos, and Gaviota quadrangles. In this report the geology
of the area is described in great detail and graphically shown on colored
lithograph maps which are accompanied by stratigraphic, structural,
and physiographic diagrams. The economic minerals of the area are also
described and mapped. These include oil and gas, asphalt, diatomite,
limestone, bentonite, flagstone, road gravel, manganese ore, and ground
water. The report describes three important oil fields — Capitan, Lompoc,
and Zaca, as well as the world 's largest diatomite quarries.
The author of this comprehensive report, T. W. Dibblee Jr., spent
some 20 years studying the region, partly as a private venture in research,
and partly in the employ of two major oil companies. Acknowledgment is
made by Mr. Dibblee to these companies, namely, the Union Oil Company
and the Richfield Oil Corporation, for their generosity in permitting the
material to be made available to the public through the auspices of the
State Division of Mines.
Respectfully submitted,
WARREN T. HANNUM, Director
Department of Natural Resources
December 1, 1949
(3)
CONTENTS
i
y
Page
ABSTRACT 7
INTRODUCTION 9
ACKNOWLEDGMENTS 9
HISTORY 9
The early explorers 9
The missions : 10
The ranches 10
Lompuc Valley 13
Santa Tnez Yalley 13
GEOGRAPHIC FEATURES 14
PREVIOUS LITERATURE 16
GEOMORPHOLOGY 17
Physiographic features 17
Drainage 19
Erosion cycles 19
STRATIGRAPHY 21
Franciscan formation 21
Honda formation 22
Espada formation 22
Jalama formation 23
The Eocene-Oligocene series 24
Eocene at Wons Canyon 25
Sierra Blanca limestone 25
Anita shale 26
Matilija sandstone 26
Cozy bell shale 27
Sacate ("Coldwater"' j formation 28
Gaviota formation 29
Alegria formation 30
Sespe formation 31
Vaqueros formation 31
Rincon elaystone 33
Lospe formation 33
Tranquillon volcanies 33
^lonterey shale : 34
Sisquoc formation 43
Foxen elaystone 44
Careaga sand 45
Paso Robles formation 47
Orcutt sand ^_^ 50
Terrace deposits 50
Alluvium 50
STRUCTURE 51
Santa Ynez Mountains 53
Southern structural block 53
Northern structural block 53
Santa Ynez fault system 54
Other faults in Santa Ynez Mountains 56
Lompoc Valley and Burton Mesa 58
Santa Rita Valley and lower Santa Ynez Valley 58
Purisima Hills 59
Los Alamos Valley and upper Santa Ynez Valley 59
San Rafael foothills 60
San Rafael Mountains 60
GEOLOGIC HISTORY 60
MINERAL RESOURCES 67
Oil and gas 67
Santa Barbara-Ventura Basin 67
Santa Maria Basin ^ 1 68
Asphalt 75
^5)
CONTENTS— Continued
Page
Diatomite 75
Types of diatomite 75
Deposits soutli of Lompoc Valley 76
Deposits of Purisima Hills and Santa Tnez Valley 77
Uses of diatomite 77
Diatomite quarries 77
Limestone 79
Bentonite 80
Flagstone 80
Road gravel . 80
Manganese oi-e 81
Water 82
LITERATURE CITED 83
INDEX 85
ILLUSTRATIONS
Plate 1. Geologic map of Point Arguello, Lompoc, and Point Conception
quadrangles In pocket
2. Geologic map of Los Olivos and Gaviota quadrangles In pocket
3. Economic map of Point Arguello, Lompoc, and Point Conception
quadrangles In pocket
4. Economic map of Los Olivos and Gaviota quadrangles In pocket
5. Geologic structure sections across southwestern Santa Barbara
County In pocket
6. Areal map showing generalized geology of southwestern Santa
Barbara County In pocket
7. A, Tectonic map of southwestern Santa Barbara County. B,
Physiographic map of southwestern Santa Barbara County In pocket
8. Structural map of the Lompoc oil field In pocket
9. Aerial photographs, southwestern Santa Barbara County In pocket
10. A, View west along Santa Ynez Range from head of Jalama
Canyon. B, View east along western Santa Ynez Mountains,
from head of El Bulito Canyon 32-33
11. A, View west across Caiiada del Gato on south flank of Santa
Ynez Mountains. B, View northeast from Gaviota showing
outcrops of Alegria sandstone 32-33
12. A, Angular unconformity between Eocene fossiliferous sandstone
(Matilija) and Cretaceous shale (Jalama?). B, View west
across Nojoqui Canyon 2.5 miles south of Buellton 32-33
13. A, Vaqueros conglomerate in Ramajal Canyon. B, Steeply dip-
ping limestone bed in Member B, lower Monterey shale, east
of Alegria Canyon 32-33
14. Platy porcelaneous siliceous shales of Member F, upper Monte-
rey, near mouth of Alegria Canyon 40-41
15. A, Thin-bedded foraminiferal shale of Member D, lower Monterey
shale, in Alegria Canyon. B, Cherty siliceous shales of Member
E, upper Monterey shale, near mouth of Jalama Canyon 40-41
16. A, View west along coast from mouth of Cuarta Canyon. B,
Typical exposure of Paso Robles terrestrial conglomerate, 7
miles east of Santa Ynez 40-41
17. Tar-soaked conglomerate and sandstone near top of Monterey
shale, east of Alegria Canyon half a mile from beach 40-41
Figure 1. Index map showing location of Point Arguello, Lompoc, Point
Conception, Los Olivos, and Gaviota quadrangles, southwest-
ern Santa Barbara County 8
2. Stratigraphic column, western Santa Ynez Mountains 38
3. Stratigraphic column, southern Santa Maria Basin 39
4. Chart showing age of formations in southwestern Santa Barbara
County 48
5. Tectonics of step-faulting in Alisal-Nojoqui area, Santa Barbara
County 52
6. Structural map of Capitan oil field, Santa Barbara County 66
(6)
GEOLOGY OF
SOUTHWESTERN SANTA BARBARA COUNTY, CALIFORNIA
(Point Arguello, Lompoc, Point Conception, Los Olivos,
and Gaviota Quadrangles)
By T. W. Dibblee Jel*
ABSTRACT
The PoiBt Arguello. Lompoc. Ix.s Olivos. Point Conception, and Gaviota quad-
rangles comprise the southwestern quarter of Santa Barbara County, and cover the
western Santa Tnez Mountains, southern portion of Santa Maria Basm, and a smaU
portion of the San Rafael Mountains. 4.u„ u;„i,or
The Santa Tnez :Mountains are composed of two topographic parts , the higher
Santa Tnez Range on the southeast, and the lower Santa Tnez Mountains on the
northwest. The Santa Maria Basin is made up on the south of the lowlands of Burton
Mesa. Lompoc Valley and Santa Tnez Valley, which are traversed by the westward-
flowin- Santa Tnez River : and on the north of the Purisima HiUs and San Rafael
foothais, in part separated by Los Alamos Valley. The region is in the mature stage of
the erosion cycle. Remnants of an earlier cycle, which reached late maturity, are
locallv preserved. . ^i. c <- -^^^^
The area mapped is composed of two stratigraphic provinces, the J>anta Inez
Alountains on the south and the Santa Maria Basin on the north. The Franciscan
formation (Upper Jurassic ? ) , a series of sedimentary and volcanic rocks with numer-
ous serpentinized intrusions, is the basement formation of both provinces. The Espada
formation (Upper Jurassic and Lower Cretaceous) is weU developed in the l-anta
Tnez Mountains and mav locally underlie the Santa :Slaria Basin. In the Santa Inez
Mountains this formation is overlain by a very thick series of predominantly marine
Upper Cretaceous. Eocene. Oligocene. and lower Miocene clastic sediments. TN ith the
exception of the lower Miocene, these are absent in the Santa Maria Basin. Marine
siliceous sediments of the Monterey and Sisquoc formations (middle Miocene through
lower Pliocene i are common to both areas but become extremely thick in the banta
Maria Basin. The former locaUy contains some volcanic rocks at the base m the J^anta
Tnez Mountains. The Sisquoc in the Santa Maria Basin is overlain by the marine
Foxen shale and Careaga sand (upper Pliocene) and the terrestrial Paso Robles and
Orcutt formations <Plio-Pleistocene).
The Santa Tnez Mountains and Santa Maria Basin are separate structural
provinces The Santa Tnez Mouutains are made up of two structural units: the
southern portion is a south-dipping homocline in a very thick stratigraphic section
uplifted on the north along the Santa Tnez fault zone, and the northern portion is an
anticlinorum composed of numerous folds developed in a thinning stratigraphic section
with manv unconformities. In the Santa Maria Basin the Burton Mesa-LompocJ^ alley-
lower Santa Tnez Vallev portion is a structuraUy rigid wedge-shaped area of Fran-
ciscan rocks covered bv a thin Tertiary-Quaternary section only slightly deformed Ihe
structure of Los Alamos and upper Santa Tnez VaUeys is a synclinal trough developed
in an extremelv thick Tertiary-Quaternary section, which is flanked by the anticlinal
Purisima HiUs and San Rafael foothills. The San Rafael Mountains withm Los Olivos
quadrangle are a mass of Franciscan rocks thrust southwestward toward the San
Rafael foothills. . , . , o. ^ t. u „
Formations of the Santa Tnez Mountains were deposited in the Santa Barbara
embavment which underwent sedimentation from Cretaceous to Pliocene time. The
Santa Maria Basin developed during Miocene time and received sediments throughout
the Pliocene and Pleistocene. Tectonic history indicates that the structures withm the
area are the result of a recurrent stress system active as far back as Oligocene. and
possibly even early Eocene or Cretaceous time, but most intense in Pliocene and
Pleistocene time.
^^ologist, Richfield Oil Corporation. Manuscript submitted for publication Jan-
uary 1949.
(7)
8
SOUTHWESTERN SANTA BARBARA COUNTY
[Bull. 150
Figure 1. Index map showing location of Point Arguello, Lompoc, Point Conception,
Los Olivos, and Gaviota quadrangles, southwestern Santa Barbara County.
Petroleum is the most important economic resource of the mapped area, which
contains three highly productive oil fields. Capitan field on the south coast produces
light oil and some gas. Lompoc and Zaca fields in the Santa Maria Basin produce
medium and heavy oil. Deposits of tar sand occur in the Purisima Hills but none have
been worked commercially.
The northwestern Santa Ynez Mountains contain large deposits of high-gi-ade
diatomite. The Johns-Manville quarries south of Lompoc are the largest diatomite
quarries in the world. Limestone deposits occur in the Miocene of the northwestern
Santa Ynez Mountains, but have been quarried only for road gravel. Sand, gravel, and
cherty shale are also quarried for road material.
1950] INTRODUCTION- 9
INTRODUCTION
The soutliwesteru portion of Santa Barbara County is an area of
Franciscan basement overlain by a sequence of predominantly marine
sedimentary formations and one local volcanic formation. The area is
made up of parts of two geologic provinces roughly separated by the
westward-flowing Santa Ynez River.
The Santa Ynez Mountains lie south of the river and trend eastward
parallel to the Santa Barbara Channel on the south. The Franciscan in
this range is overlain by a nearly continuous .series of predominantly
marine sedimentary formations ranging in age from uppermost Jurassic
to Pliocene. These formations are very thick and conformable on the south
flank, but thin rapidly to the north, where there are several uncon-
formities. Structurally the high southern portion of this range is a south-
dipping homocline uplifted on the north along the Santa Ynez fault
sj^stem, while the lower northern portion is largelj- an area of folding.
The lowland area north of the river takes in the southern portion of
the Santa ]\Iaria Basin, which within the area mapped comprises the
Lompoe Valley, Santa Ynez Valley, Burton Mesa, Purisima Hills, and
parts of Los Alamos Valley and San Rafael foothills. The stratigraphic
section of this basin consists of marine ]Mioceue and Pliocene and terres-
trial Pleistocene which becomes very thick along the Los Alamos synclinal
trough. The Burton Mesa, Purisima Hills, and San Rafael foothills are
anticlinal areas ; the intervening valleys are sjTiclinal.
The small portion of the San Rafael ^Mountains mapped is a block
of Franciscan rocks thrust southwest toward the Santa ]\laria Basin.
ACKNOWLEDGMENTS
For permission to publish the geologic maps and this report, the
writer is deeply indebted to L^nion Oil Company of Califoimia, and to
Richfield Oil Corporation. The writer is also indebted- to R. K. Cross,
for the portion of the area mapped by him ; to M. L. Xatland and W. T.
Rothwell, for assistance rendered in microfaunal determinations; to
A. W. Hughes, and to T. W. Dibblee and C. E. Russel, manager and
foreman, respectively, of Rancho San Julian, for their cooperation and
for use of the ranch house as headquarters while carrying on the work ;
and to the owners and superintendents of the various ranches through-
out the area.
HISTORY
The Early Explorers
The Santa Barbara coa.stal area was first explored by Cabrillo and
Ferrelo in two small ships, in October 1542. After exploring the south
coast and the islands thej- encountered such stormy weather where the
coast "veered northward" (Pt. Conception) that they were forced to
remain several days in the channel before resuming their journey. They
spent several days at or near Refugio (Refuge) Beach, where they were
met by friendly Indians who offered fresh sardines and other food.
The earliest land expedition was led by Gaspar de Portola. accom-
panied by Padre Junipero Serra and his ardent Franciscan monks, in
1767, who took possession of Alta California in the name of the King
of Spain. In traversing what is now Santa Barbara County the party
10 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
traveled up the coast. Along the channel coast the native Indians Avere
so friendly as to oft'er an abundance of seeds, acorns and fresli fish, in
return for beads and other trinkets, and even begged the travelers to
remain with them and share their huts.
This same route was followed by the expedition of Juan Bautista
de Anza in 1774 and 1775.
Spanish explorers and mission padres were very much impressed
by the beautiful region that is now Santa Barbara County, which
bears striking resemblance to their mother country. They found a brush-
covered mountain ridge (Santa Ynez Range) sloping southward to grassy
foothills bordering the sea, and northward to rolling foothills and fertile
valleys covered with luxuriant grasses and scattered groves of oak. The
climate was ideal the year round. The area offered great possibilities as
grazing land for cattle and sheep. As the Spanish ' ' conquistadores "
entered this land during the 18th century the primitive life of the native
Indians gave way to the gay and colorful ''hacienda" era that centered
in the great ranches and Franciscan missions. The Spanish crown
rewarded the soldier-explorers with large grants of land, known as
"ranchos, " and the padres received large tracts on which to establish
their missions.
The Missions
Mission Santa Barbara, founded in 1786, was the first of the three
missions established by the Franciscan padres (fathers) in what is
now Santa Barbara County to convert the native Indians to Christians
and into useful subjects. The other two missions were established in the
Santa Ynez River valley.
In the lower portion of the valley Mission La Purisima Concepcion
was founded December 8, 1787, by Padre Lasuen, presidente of the Fran-
ciscan missionaries and successor to Padre Junipero Serra. This was the
eleventh of the 21 missions established in California; it was erected
near the present site of the Veterans Memorial Building at Lompoc. The
mission served the growing community of Indian neophytes until the
earthquake of 1812 which almost completely destroyed it. It then became
known as La Mision Vieja de la Purisima. In 1816 the mission was
rebuilt at a new site at the mouth of Purisima Canyon, and was served
by Franciscan friars until confiscated and sold by Mexican politicians
in 1845. It was then abandoned and became a ruin, but was restored
after 1933 by the federal government and made into a state park and
museum.
In the upper portion of Santa Ynez River valley. Mission Santa
Ines was founded at its present site at Solvang on September 17, 1804,
by Padre Estavan Tapis, a.s the nineteenth mission established. The
church and buildings were completed in 1812. The earthquake of that
year damaged it, and the present church was completed in 1817. The
mission was served by the Franciscan friars and was the site of the first
seminary (priesthood) college in California, established in 1844. The
mission was confiscated after the Mexican revolution, but is now a parish
church in charge of the Capuchin Franciscans.
The Ranches
The historic background of southwestern Santa Barbara County
centers in the great ranchos into which it was divided. These large tracts
of land granted to the Spanish soldier-explorers in commendation of
1950] HISTORY 11
their services, are shown on the old topoc^raphic maps of Lompoc and
Guadalupe quadrangles (scale 1 inch ^ 2 miles), issued by the U. S.
Geological Survey in 1905.
At each rancho the grantee built at or near a large spring an
hacienda, a long, low house of adobe walls 2 or 3 feet thick, with a long
front porch. Most of the houses were shaded by trees or grape arbors.
Helping hands occupied smaller outbuildings. The ranchos were stocked
with herds of Spanish cattle, which roamed at large, there being no
fences. In the spring of each year rodeos (roundups) were held, during
which the cattle were herded together, calves branded and steers sold.
In addition, large numbers of sheep were raised on some ranchos.
Although periodic droughts caused the loss of much livestock, the ran-
cheros prospered from the sale of beef, hides, tallow, mutton, and wool
while California was under the Spanish and Mexican flags, although
much of the business was with Yankee traders from Boston and New
York. Aside from the working of cattle and sheep there was little to do,
so that the life of the Californians took on a gay fiesta spirit.
When American explorers and troops invaded California during the
Gold Rush era of the late forties, the rancheros offered no resistance, as
they prospered from business with Yankee traders, and resented being
taxed to the limit by greedy Mexican politicians. Being good Catholics,
the rancheros likewise resisted confiscation of the missions. In 1846
General John C. Fremont and his Yankee troops came south by way of
Foxen Canyon and over San Marcos Pass, and took Santa Barbara
without resistance.
After California was annexed to the United States in 1850, the
"gringos" (Yankees) settled in Santa Barbara County in ever increasing
numbers, intermarried with the Spanish-Californians, and, since they
were more ambitious and energetic, gradually acquired lands of the
ranchos from the descendants of the grantees. As the ranchos became
divided and subdivided into smaller and smaller tracts, fences were
erected, and the valleys were cultivated. The semi-wild, long-horned
Spanish cattle were gradually replaced by the large chunky ' ' white-face ' '
Herefords as the main source of beef, and by docile Holstein and Guern-
sey cows as the source of dairy products.
One of the most colorful of the Spanish ranchos is Rancho San Julian,
whose history is in general typical of that of the other ranchos in the area.
In 1817 the Company of the Presidio of Santa Barbara established
Rancho San Julian as a source of meat supply for the soldiers of the
King of Spain, and it was then kno-^vn as Rancho Nacional. At that time
the first section of the present adobe house was built and served as head-
quarters. In commendation for his many military services several ranchos
were granted by the Spanish Crown to Capitan Jose Antonio de la Guerra
y Noriega, who was born in Novales, Spain, in 1779, from a long line
of distinguished ancestors. He came to California in 1800 and was sta-
tioned at Santa Barbara in 1806 where he served for 24 years as com-
mandante of the Presidio and was commissioned * ' Habilitado General ' '
(Resident General) of both Californias. In 1837 he became grantee of
Rancho San Julian, comprising 11 leagues or 48,000 acres. In addition
he was granted Rancho Los Alamos in Los Alamos Valley area, and
Ranchos Simi, Tapo, and El Conejo in what is now Ventura County.
12 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Upon the death of Don Jose Antonio de la Gnerra y Noriega, Ranclio
San Julian was inherited by his sons, one of whom was Pablo de la Guerra,
and it later passed into the ownership of Don Gaspar Orena, their brother-
in-law married to Maria Antonia de la Guerra.
In 1867 Thos. Bloodgood Dibblee and his brother, Albert Dibblee,
came to California from New York and purchased Rancho San Julian
from Gaspar Oreiia and his wife, and a year later T. B. Dibblee married
Francisca de la Guerra, daughter of Pablo de la Guerra. T. B. Dibblee
stocked the rancho with one of the finest herds of registered shorthorn
beef cattle known which for many years produced top grade foundation
stock.
Soon after the Dibblee brothers acquired Rancho San Julian they
formed a partnership with W. W. Hollister and purchased the adjoining
Ranchos Espada, Lompoc, Mission Vieja de la Purisima, Caiiada de
Salsipuedes, Las Cruces, and Nuestra Senora del Refugio. These vast,
unfenced rangelands, totaling some 150,000 acres, were managed by
T. B. Dibblee, and the San Julian ranch house (Casa de San Julian)
was headquarters. The lands were stocked with both cattle and sheep.
For the springtime rodeos, the vaqueros rode out many miles
from Casa de San Julian to gather the cattle of each local area into
corrals conveniently located. They were joined and assisted by vaqueros
from neighboring ranchos in order to identify their respective cattle.
After the cattle were gathered in, the calves were branded, and steers
in good condition and any other cattle to be sold were separated out and
driven to headquarters for sale. At nightfall the vaqueros often camped
and ate barbecued steak under the oak trees. The rodeos lasted several
weeks, often several days being required to work each local area. After
the cattle brought in to headquarters were sold, they were driven to
Gaviota Beach and loaded on board ship at a loading pier, built by
T. B. Dibblee, and shipped to San Francisco, the main market. After the
Pacific Railroad was built from that city south to Guadalupe, in Santa
Maria Valley, in the nineties, the cattle were sometimes driven 30 miles
. to that station (it took 4 days) and shipped north by rail.
The lands of Dibblee and Hollister were at one time stocked with
more than 50,000 head of sheep besides the cattle. This large herd con-
sisted of many flocks each herded by a lonely shepherd, usually a
Spanish-Basque, and his faithful dogs. He spent his lifetime in the hills
with his flock, and was supplied each two weeks with provisions from
headquarters. Several times a year he brought his flock in to headquarters
to be sheared, dipped, and doctored, and to wean the lambs, and have
the yearling wethers separated to be shipped north to market. Sometimes
these were driven all the way to San Francisco, fed on the way, and sold.
In the seventies the Dibblee-Hollister partnership was dissolved and
the lands and livestock divided. Ranchos Espada, Lompoc, and Mission
Vieja de la Purisima were sold. Ranchos Canada de Salsipuedes, Las
Cruces, and Nuestra Seiiora del Refugio went to W. W. Hollister and
were inherited by his son, James J. Hollister, present owner. The western
portion of Rancho San Julian went to A. Dibblee and was sold years later.
The eastern portion of Rancho San Julian was retained by T. B. Dibblee
and his wife, Francisca de la Guerra, and upon their death was inherited
by their seven children, one of whom is T. Wilson Dibblee who succeeds
his father as manager.
1950] HISTORY
13
Rancho San Julian enjoys the distinction of being one of the few
remaining California ranches owned by the descendants of its grantee.
Still used as headquarters is the original adobe ' ' hacienda" with two-foot-
thick walls, of which the west wing was built by the Spanish soldiers in
1817. the central portion by Captain Jose Antonio de la Guerra in 1837,
and the east wing by T. B. Dibblee about 1875.
Lompoc Valley
Rancho Lompoc. which included the wild, verdant valley now called
Lompoc, was purchased by a determined group of California Yankees
in 1874 who foresaw its tremendous agricultural possibilities. They set
aside a corner of the rancho as a townsite and in 1875 founded the town
of Lompoc. They advertised the valley 's potential greatness throughout
America and soon farmers, dairymen, tradesmen, and professional men
from every section arrived. They built up the town of Lompoc to a
thriving little city of 6,500.
Lompoc Valley is one of the most intensively and successfully
farmed areas in the nation. Almost all of its rich alluvial soil is under
irrigation and more than 50 varieties of vegetables and herbs are pro-
duced on a year-round basis, which yield an annual income to Lompoc
running into millions of dollars.
Lompoc Valley is most famous for its acres of flowers. More than 500
varieties of flowers are groAvn commercially for seed on over 2,500 acres
of the valley floor, which in spring and summer make a floral display as
colorful as can be imagined. Ideal climatic and soil conditions enable
I Lompoc Valley to produce a wide variety of flower seed with a high
« germination rate.
Rancho Jesus ]\Iaria, which covers the sandy, windswept Burton
Mesa, was acquired by the U. S. Army during the last war and built
into one of California's largest military installations. The reservation
covers 96,000 acres and was activated during the war. The Army plans
to use it as a training ground for the peacetime military force.
Santa Ynez Valley
Upper Santa Ynez Valley has always been a grazing area as it is
too arid and rolling for year-round farming. In late years much of it has
been dry-farmed for grain and barley. A famous artesian spring issues
from the southern portion, of which the water was used by native Indians
who inhabited the vicinity until recent j^ears. The water was also used
by the Franciscan friars to irrigate fields near j\Iission Santa Ines.
Adjacent to this big spring is the pueblo of Santa Ynez, the oldest in
Santa Ynez Valley, from which the valley derives its name. The pueblo
consisted of a large wooden hotel, garage, and store, and served as a
stopover for the stages going to and from Santa Barbara over San Marcos
Pass. The old hotel burned down about 1935 and the pueblo never grew.
The village of Los Olivos is built around f amous '* Mattel 's TaA^ern",
which used to serve as a stopover for stage-coaches traveling between
Santa Barbara and San Francisco. The lower portion of Santa Ynez
Valley has been developed into a small but intensively farmed area,
largely by immigrants from Denmark who settled there. About 1910 a
group of Danes established near the Santa Ines mission a townsite which
they named "Solvang" (Sunny Valley) . It is now a thriving community
14 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
inhabited by several hundred Danes. Three miles down, the highway
village of Buellton was centered around Andersen's Inn, home of
"split pea soup."
GEOGRAPHIC FEATURES
Location and Method of Work. The area mapped comprises the
southwestern portion of Santa Barbara County, which lies about midway
between Santa Barbara and Santa Maria. The area totals about 700
square miles.
The base maps used for plotting the areal geology are five 15-minute
topographic quadrangles, scale 1 :62500, namely Point Arguello, Lompoc,
Los Olivos, Point Conception, and Gaviota. These were issued in 1941
by the U. S. Army Corps of Engineers.
Areal geology was mapped in 1929 and 1930, then from 1936 to
1939, in detail, on aerial photographs (approximate scales, 1 :20000 and
1:24000). This geology was later transferred to the 15-minute topo-
graphic quadrangles. Minor details have necessarily been omitted because
of the much smaller scale of the quadrangles. The areal mapping was done
by the writer throughout the area with the exception of that portion of
the San Rafael foothills lying west of Santa Agueda-Lisque Canyons in
northern Los Olivos quadrangle, which was mapped by R. K. Cross, but
checked in the field by the writer. The geology of the Purisima Hills was
taken from U. S. Geological Survey Oil & Gas Investigations Preliminary
Map 14, with slight modifications by the writer.
Accessibility and Transportation. With the exception of the higher
part of the Santa Ynez Range, all points within the area lie mthin 2 miles
of roads. The main coastal highway, U. S. 101, runs from Santa Barbara,
18 miles east of Capitan, to Santa Maria, 18 miles northwest of Los
Alamos. Towns within the area are all connected by good paved roads.
Throughout the area are many secondary roads, both county and private.
The Southern Pacific railroad follows the coast throughout the area.
Population and Industry. Four towns lie along the course of the
Santa Ynez River. Lompoc (population 6500) is the largest and most
westerly. Camp Cooke is located 10 miles northwest, and Mission La
Purisima Concepcion 3 miles northeast of Lompoc. Farther east along
the river are Buellton (population 300), Solvang (400), site of Mission
Santa Ines, and Santa Ynez (250). Other small towns are Los Olivos
(250) and Los Alamos (300).
The fertile lands of Los Alamos, Lompoc, and lower Santa Ynez
Valleys are extensively cultivated for alfalfa and truck-gardening. They
are irrigated from numerous wells. Upper Santa Ynez Valle}^ is largely
dry-farmed. The luxuriant grasslands of the rolling hills throughout
the area are devoted to pasturing of beef and dairy cattle.
Land Divisions. With the exception of the United States National
Forest land in the San Rafael and higher Santa Ynez Mountains, which
is sectionized, practically all of western Santa Barbara County is covered
by original Spanish land grants. Only very small areas not covered by
the grants are sectionized. These land grants and sections are shown only
on the Guadalupe and old Lompoc quadrangles, scale 1 :125,000, issued by
the U. S. Geological Survey in 1943.
1950] GEOGRAPHIC FEATURES 15
CUmafe. The climate of southwestern Santa Barbara County is
equitable and mild throughout the year, and semi-arid. Summers are kept
cool by low marine fog at night, and by the prevailing northwest sea
breeze during the day. Winters are mild, but night temperatures often
fall below freezing in inland valleys.
Precipitation is in the form of rainfall and may occur any time from
October to May. but in most years heavy rains come only during the
winter months. Annual rainfall averages about 15 inches throughout the
area except in the Santa Ynez and San Rafael Mountains, where it
averages about 25 inches.
Exposures and Tegetation. Exposures throughout the area mapped
are determined by (1) the character of the underlying formation, and
(2) ruggedness of the terrain. The most prominent exposiu'es occur in
mountainous areas underlain by hard, resistant rocks, and the poorest
in low. rolling hills underlain bv soft, easilv weathered sediments. The
area contains several types of natural vegetation whose distribution is
determined by the following factors: (1) the character of the under-
lying formation: (2) amount of residual soil; (3) steepness of slope;
and {i} local climate. In general, steep rock\" slopes are covered by
brush, and gentle slopes with a heavy soil mantle by grasses and annual
herbs.
The high rugged portion of the Santa Ynez Range east of Gaviota
Canyon contains the best exiDOSures in the area mapped. Tilted sand-
stone beds form prominent ledges, especially on the south slope. Shales
are less prominently exposed, but have very little soil cover. Regardless
of the underlying formation, this entire range is covered with a very
dense impregnable chaparral-tA-pe brush, composed mainly of lilac,
scrub oak. and other shrubs.
In the lower portion of the Santa Ynez Range exposures are good
on the rugged south slope west of Gaviota Canyon, but elsewhere are
less prominent. Throughout this area brush, either the heavy chaparral
type or low sage brush, grows only on hard, resistant formations such as
sandstone, conglomerate, hard shales, and volcanic rocks. Clay shale
formations and softer shales of the Monterey readily weather into a
heavy adobe .soil which supports only gra.sses and annual herbs. Hard
formations which fracture readily, such as Monterey cherty shale, are
for the most part covered by live oak timber. Since the various types of
vegetation are influenced by the underlying formations, their disti-ibu-
tion is a great aid in mapping.
The Purisima Hills are more or less covered with soil, but there
are good local exposures. The vegetation is a mixture of three tyi^es,
namely grasses and annual herbs, low brush, and live oak timber. The
underlying formations have only slight influence on the distribution of
these three ty|ies. In general, steep slopes are covered by brush, frac-
tured shale areas by timber, and gentle slopes with deep soil, by grasses.
In the western Purisima Hills north of Lompoc oil field is a very dense
stand of scrub pine growing on Sisquoc diatomite.
The low rolling San Rafael foothills are made up of loosely con-
solidated gravels and clays of the Paso Robles formation and are covered
with a thick soil mantle. Consequently there are few exposures. This is
an area of grasslands, dotted vrith oaks. The same t.^i^e of vegetation
prevails in the San Rafael Mountains, but with the addition of scat-
tered digger pines.
16 SOUTIIWESTEKX SANTA BARBARA COUNTY [Bull. 150
PREVIOUS LITERATURE
The earliest geological investigation in southwestern Santa Bar-
bara County "was made by Thomas Antisell,^ who accompanied a party
of engineers sent by the United States War Department to explore a
route for a transcontinental railroad in 1856.
The first geologic map and report published on the area were issued
in 1907, after Arnold and Anderson mapped the geology of the Guada-
lupe and old Lompoc quadrangles on the scale of 1 : 125,000.- This recon-
naissance work covered all of the quadrangles except a part of the Santa
Ynez Mountains. In 1925 the southwestern portion of the adjoining
Santa Ynez quadrangle was mapped by R. Nelson.^
The geology of the western Santa Ynez Mountains was described
briefly by Reed ^ and by Reed and Hollister.^
In 1943 Kelley ^ mapped and described in detail the Eocene section
of Santa Anita Canyon area.
No detailed information was published on the Santa Maria Basin
until 1943, when the U. S. Geological Survey studied and mapped the
stratigraphy of that area,'^ and also of the southeastern Purisima, Santa
Rita, and Santa Rosa Hills. ^ The Survey has just completed a detailed
study and map of the ground-water resources of Lompoc and Santa Ynez
Valleys.*^
The Vaqueros fauna has been discussed by Loel and Corey ^° ; that
of the Oligocene and Eocene by Arnold and Anderson, ^^ Woodring,^^
and Schenck and Kleinpell.^^
Geology of the Lompoc and Capitan oil fields has been described in
California State Division of Mines Bulletin II8.1*
I Antisell, Thomas, Geolog-ical report: Pacific Raih-oad Survey, vol. 7, pt. 2, chap.
10, pp. 65-74, W^ashinpton, D. C, 1856.
-Arnold, R., and Anderson, R., Geologv and oil resources of Santa Maria oil dis-
trict, Santa Barbara County, Calif.: U. S. Geol. Survey Bull. .322, pp. 1-161, 1907.
3 Nelson, R. N., Geology of the hvdrographlc basin of the upper Santa Ynez River,
Calif.: Univ. California Dept. Geol. Sci. Bull., vol. 15, no. 10, pp. 327-396, 1925.
* Reed, Ralph D., Geology of California, 355 pp., Tulsa, Oklahoma, Am. Assoc.
Petroleum Geolog'ists, 1933.
5 Reed, Ralph D., and Hollister, J. S., Structural evolution of southern California,
pp. 86-97, Tulsa, Oklahoma, Am. Assoc. Petroleum (ieologists, 1936.
8 Kelley, P. R., Eocene stratigraphy in western Santa Ynez Mountains, Santa
Barbara County, California: Am. Assoc. Petroleum Geologists Bull., vol. 27, no. 1,
pp. 1-19, 1943.
^ Woodring, W. P., and others. Stratigraphy and paleontology of the Santa Maria
district, California: Am. Assoc. Petroleum Geologists Bull., vol. 27, no. 10, pp. 1335-
1360, 1943. . . . Geologic map of Santa Maria district, Santa Barbara County, Calif.,
U. S. Geol. Survey Oil and Gas Inv., Prelim. Map 14 (in 6 sheets), 1944.
8"Woodring, W. P., and others, Geologj- of Santa Rosa Hills — eastern Purisima
Hills district, Santa Barbara County, California: U. S. Geol. Survey Oil and Gas Inv.,
Prelim. Map 26, 1945.
Upson, J. E., Thomasson, H. G., and others, Geology and water resources of Santa
Ynez River vallev, Santa Barbara County, California : U. S. Geol. Survey dupUcate
rept, pp. 1-322, June 1947.
^0 Loel, W., and Corey, W. L., The Vaqueros formation, lower Miocene of Cali-
fornia, I Paleontology: Univ. Cahfornia Dept. Geol. Sci. Bull., vol. 22, pp. 31-410, 1932.
II Op. cit.
12 Woodring, W. P., Upper Eocene orbitoid foraminifera from the western Santa
Ynez Range, California, and their stratigraphic significance : San Diego Soc. Nat. Hist.
Trans., vol. 6, no. 4, pp. 145-170, 1930.
1* Schenck, H. G., and Kleinpell, R. M., The Refugian stage of the Pacific Coast
Tertiary: Am. Assoc. Petroleum Geologists Bull., vol. 20, no. 2, pp. 215-225, 1936.
i*Dibblee, T. W. Jr., Lompoc oil field: California Div. Mines Bull. 118, pp. 427-
429, 1943.
Kribbs, George R., Capitan oil field: California Div. Mines Bull. US, pp. 374-376,
1943.
1950] GEOMORPHOLOGY 17
GEOMORPHOLOGY
Physiographic Features
The various physiograpliie features referred to within the quad-
rangles mapped, and the principal streams to which reference is made,
are shown on plate IB. Details of topography and drainage are shown
on the topographic quadrangles.
Santa Tjicz Mountains. The Santa Ynez Range is one of the east-
ward-trending Transverse Ranges of southern California. It extends
farther west than the other Transverse Ranges, paralleling the Santa
Barbara channel on the south and extending continuously from Point
Arguello eastward some 75 miles to Matilija Canyon in Ventura County.
Only the western portion of the range is within the quadrangles mapped,
where it is composed of two parts, the higher Santa Ynez Range, and the
lower Santa Ynez Mountains.
Referred to as the '"higher Santa Ynez Range" is the prominent
mountain ridge extending eastward, unbroken from Gaviota Canyon
beyond the area mapped into Ventura County. This mountain range was
formed as a block uplifted along the Santa Ynez fault at its northern base.
The course of this fault zone is marked by short rift canyons, saddles, or
a sharp break in slope. South of the fault the range rises abruptly, form-
ing a bold escarpment, to an even crest line averaging about 2500 feet
elevation within Los Olivos quadrangle, but rising higher to the east.
South of this crest the range slopes gently seaward. As the range is sculp-
tured out of sedimentary formations dipping south, the crest is essen-
tially a strike ridge ; the north flank is characterized by step-like topog-
raphy and the south flank by dip-slopes. The drainage system is
regular. Canyons on the north flank are short and steep, but on the south
flank they are long, and the streams have reached grade and have
developed small flood plains.
The area referred to as the "lower Santa Ynez Mountains" com-
prises the hills lying between the "higher Santa Ynez Range" and the
Santa Ynez Valley, and extending westward to Point Arguello. The
southern crest of these hills averages about 1400 feet elevation and
extends from Las Cruces due west to the south side of Jalama Canyon.
It is cut through by Santa Anita Canyon. This ridge is topographically
and geologically the westward extension of the higher Santa Ynez
Range, being similar in every respect, but on a smaller scale. From the
head of Jalama Canyon another ridge branches off from the southern
ridge and extends north of west through a high mass of hills to the
prominent ridge of Tranquillon Mountain, which forms the main divide
and backbone of the extreme western Santa Ynez Mountains. The drain-
age system is somewhat irregulaj* because of complex geology. The Santa
Rosa Hills average about 1600 feet elevation and form the northern crest
of the lower Santa Ynez Mountains. This ridge extends from Salsipuedes
Creek eastward to Nojoqui Creek. The hills extending westward and east-
ward from the Santa Rosa Hills are cut through by several major north-
ward trending canyons antecedent to them. The Santa Rita Hills are
geologically part of the Santa Rosa Hills but are separated by the Santa
Ynez River which forms an antecedent canyon between them.
San Fafael Mountains. The San Rafael Mountains average about
4000 feet elevation and form the most southerly of the northwest-trending
Coast Ranges. Only a very small portion of the southwest flank lies within
18 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Los Olivos quadrangle. The slope is steep, and as it is made up of serpen-
tine and Franciscan rocks, it is characterized by numerous landslides.
The range has been thrust up along the Little Pine fault, which is marked
by an abrupt change in slope between the mountains on the upthrown
side and the San Rafael foothills to the southwest.
San Bafael Foothills. Referred to as the San Rafael foothills is the
broad area of low rolling hills southwest of the San Rafael Mountains.
They are the result of gentle anticlinal uplift, and since they are made up
of soft formations they are characterized by low, rounded ridges of more
or less equal height, and canyons which have reached grade. These hills
are cut through by the major canyons, antecedent to them, draining south-
westward from the San Rafael Mountains.
Purisima Hills. The Purisima Hills are an anticlinal uplift. Their
main crest averages about 1500 feet elevation, and trends about N. 75° W.
They extend into the Santa Maria quadrangle on the northwest where
they merge into Burton Mesa on the west. The crest is located about mid-
way between the northern base and the southern base except in the west-
ern portion, where it approaches the latter. The hills are of moderate
relief. The drainage pattern is normal for an area of anticlinal uplift,
with consequent canyons cut do\\ai each flank. The streams have reached
grade and have developed small flood plains. The southeast end of the
Purisima Hills is cut through by the antecedent canyon of Zaca Creek.
Santa Yn ez Y alley. The Santa Ynez Valley is a synclinal area which
has undergone little or no uplift. It is separated by the southeast end of
the Purisima Hills just north of Solvang into an upper or northeastern
portion, and a lower or southwestern portion.
The upper Santa Ynez Valle}' is a broad, roughly triangular valley
with an average elevation of 700 feet. It is essentially a structural trough,
but the southern portion has been formed by lateral stream erosion.
Streams do not follow this valley but drain southward across it into the
Santa Ynez River at its southern edge. Some of these have cut below the
original valley surface, indicating slight uplift. The river has cut several
terraces and a small flood plain down to an elevation of some 500 feet.
Geologically the upper Santa Ynez Valley is a synclinal trough extending
through Los Olivos northwestward through a gap between the Purisima
Hills and San Rafael foothills into Los Alamos Valley.
The lower Santa Ynez Valley averages about 350 feet elevation and
is a synclinal trough between the eastern Purisima Hills and the Santa
Ynez Mountains. This portion is followed by the Santa Ynez River
which has destroyed the original valley surface and formed a flood
plain. About 6 miles west of Buellton the river leaves this valley and cuts
south between the Santa Rosa and Santa Rita Hills; but the synclinal
trough continues westward through Santa Rita Valley, where the
original depositional surface has been elevated and warped, but is still
preserved locally. The Santa Rita Valley is at an elevation of about 600
feet and is separated by Ioav saddles from Santa Ynez and Lompoc
Valleys.
Lompoc Yalley. Lompoc Valley is geologically the westward exten-
sion of the lower Santa Ynez Valley synclinal trough, but is consider-
ably broader. It has undergone slight uplift and erosion, so that the
original sand}^ surface has been broadly warped and preserved only in
the northeastern and southwestern portions, at an average elevation of
1950] GEOMORPHOLOGY 19
300 feet. The Santa Ynez River has cut throug'h tliis sandy valley and has
formed a flood plain, referred to as ' ' Lompoc Plain ' ' by Upson/^ about
2 miles wide and about 11 miles long at an elevation of less than 100 feet.
Burton Mesa. To the northwest, Lompoc Valley blends into a low
mesa-like area known as Burton Mesa, which averages about 400 feet in
elevation. This is an uplifted peneplain locally dissected by youthful
canj'ons.
Coastal Terraces. At least three wave-cut terraces are developed
along the coast. The lowest occurs throughout the coast at an elevation of
50 to 150 feet. It forms a broad but much dissected coastal plain north
and east of Point Conception, and also near Point Arguello. A higher
terrace, at an elevation of about 200 feet, is well developed against
Burton Mesa, but is preserved only as small remnants elsewhere. Isolated
remnants of a still higher terrace occur at an elevation of about 500 feet
on the seaward slopes of the hills northeast of Point Conception and
Point Arguello, and also near Alegria and Refugio Canyons.
Drainage
The drainage systems within each physiographic province have
been described. With the exception of the north flank of the Purisima
Hills which drains into Los Alamos Valley, the entire area north of the
crest of the Santa Ynez Mountains is drained by the Santa Ynez River
system. All tributaries gather into this river which flows west into the
ocean at Surf. The river generally follows the Santa Ynez-Lompoc
Valley synclinal trough, but in many places cuts south of it into the
foothills of the Santa Ynez Mountains. The general drainage system is
shown on plate IB.
During heav.y rainy seasons the Santa Ynez River carries consider-
able runoff. The river generally runs throughout the year, but drys up
locally during prolonged dry seasons. Other streams are intermittent,
but some of the major streams in the Santa Ynez Mountains run
throughout the year. ''4a4m^rr?4jtaai£a
Springs are abundant in the Santa Yn^^Sp^,F:ji^^>a;^J-
some occur in the Purisima Hills, and a If^Y. ' '^ ^'^'^^'^Hu^l^
The valleys are generally devoid of spring . -pt Jw,^^k
artesian spring at Santa Ynez.
Erosion Cycles
Southwestern Santa Barbara County has been through at least two
cycles of erosion during the Pleistocene. The first cycle occurred during
middle Pleistocene time prior to deposition of the middle or upper
Pleistocene Orcutt sand ; the second took place during late Pleistocene.
During the first cycle, Burton Mesa, Santa Rita Hills, and the hills
north of Canada Honda were peneplained ; the lower Santa Ynez Moun-
tains, Purisima Hills, and San Rafael foothills were probably reduced to
late maturity or an old-age stage of erosion. This erosion surface is pre-
served in the western and southeastern Purisima Hills, but elsewhere
there are onlj^ small remnants. Hills which once occupied the vicinity of
Solvang and Santa Ynez were peneplained to form the southern part of
upper Santa Ynez Valley. This erosion period was followed by filling of
Lompoc, Santa Ynez, and Los Alamos Valleys by sand of the Orcutt
formation and terrestrial gravels.
IS Op. cit
20 SOUTHWESTERN SANTA BARBARA COUNTY [BuU. 150
The second cycle was inaugurated by renewed uplift of the entire
region by compressive forces. The mountains and hills were uplifted
to their present heights, thereby causing a renewed downcutting of
canyons by streams. The peneplained surface of Burton Me.sa and the
hills north of Cafiada Honda were elevated at this time, and were partly
dissected by youthful streams. Lompoc and Santa Ynez Valleys were
likewise raised but to a lesser amount than the adjacent highlands, and
the Santa Ynez River deepened its channel. Regional uplift during the
second cycle was recurrent in three or four stages, as indicated by that
many terraces along the Santa Ynez River valley, and also by at least
three wave-cut terraces along the coast.
The final stage of the second cycle, at the close of Pleistocene or
beginning of Recent time, was marked by lateral erosion by streams to
form flood-plains in their respective valleys or canyons. During this
stage the Santa Ynez River developed the flood-plain of lower Santa
Ynez Valley, and the broad, level plain of Lompoc Valley. The level
portion of Los Alamos Valley was also formed by lateral stream erosion.
As, or after, these flood-plains were formed the flat lower valleys became
filled with terrestrial alluvium. This was followed, or possibly accom-
panied, by regional subsidence, or rise of sea level, of about 300 feet
maximum, which caused the lower parts of the alluviated flood-plains
to be submerged below sea level ; but they were not drowned, as deposition
of alluvium apparently kept pace with subsidence. However, in higher
areas away from the sea most streams are deepening their channels
through the alluvium, indicating slight recent uplift of these areas.
The southwestern portion of Santa Barbara County is an excellent
example of an area in which all physiographic features are the direct
result of uplift by compressive forces active during Quaternary time, a
condition general throughout the Coast Ranges of California. In general,
the amount of relief is proportional to the amount of uplift. The highest
areas, such as the Sau Rafael and higher Santa Ynez Ranges, have under-
^e8.e"th^ ^^iSt^BtjiRiW^iilltJ -of uplift, having been elevated along major
■"""'"*""" i^^fp^fik^W'^Wpintiatnre stage of erosion, being characterized
JiffA/^-Sliii^'fed canyons. The hilly areas, such as the lower
ff^!ri'sTTL'urisima Hills, and San Rafael foothills, have
midergone moderate uplift, mainlj^ by compressive folding. They are in
the middle to late mature stage of erosion, being characterized by
rounded crests and canyons with small flood plains. The valleys are
synclinal troughs between the uplifted areas. They have been raised only
slightly and have been subjected to comparatively little erosion.
The submerged area adjacent to the Santa Ynez Mountains has
undergone relatively little uplift as compared to the land area. This is
indicated by the fact that only the youngest formations of the range,
namely, the Sisquoc and Montere^^ formations, crop out along the coast,
and generally dip seaward, indicating relative uplift of the land area.
The sea is constantly eroding landward, and in the vicinity of Point
Arguello and east of Gaviota the waves have cut through the Sisquoc
into the more resistant Monterej' shale. Point Arguello and Point Con-
ception are essentially anticlinal uplifts exposing resistant Monterey
shale, forming points jutting out into the sea to make right-angle bends in
the coast line. Aside from these two prominent points, the coast line is
fairly straight, indicating that the mature stage of the wave erosion
cycle has been reached.
1950] STRATIGRAPHY 21
STRATIGRAPHY
Franciscan Formation
The Franciscan formation of Santa Barbara County is typical of
that found elsewhere in California, being composed of sandstone, clay
shale, radiolarian chert, and basalt, of Upper Jurassic ( ?) age. It is the
oldest formation in the county and forms the so-called ' ' basement upon
which vounger formations were laid down.
The Franciscan is widely exposed along the southwest slope ot the
San Rafael Mountains, of which a small portion was mapped m the north-
east corner of Los Olivos quadrangle. An exposure of clay shale mapped
as the Honda shale in the extreme western Santa Ynez Mountains may
be a member of the Franciscan. Both exposures are intruded by serpen-
tinous rocks. Wells drilled on Burton Mesa and in the Lompoc oil field
encountered the Franciscan below the Miocene formations.
In the San Rafael Mountains the various members of the Franciscan
strike due east to N. 60° ^Y., and generally dip steeply north. However,
the rocks are so highly sheared and brecciated, and injected by numerous
masses of serpentine, that the sequence could not be worked out. lie
Franciscan here is composed of four rock types, sandstone, clay shale,
varicolored chert, and basalt.
The sandstone is bluish green when fresh but weathers brown; it is
more or less medium grained, arkosic, and is composed of angular grams
mainlv of feldspar. It is massive and hard, but closely jointed so that it
does not form prominent outcrops. ]\Iuch of it contains calcite vemlets.
It forms poor exposures and is generally the only rock m the Franciscan
which supports brush. , ^ • i
The clav shale is dark brownish green to black and is nearly every-
where in a very highlv sheared and brecciated condition. As a result it
seldom crops out, but instead forms a deep clayey adobe soil which sup-
ports grass. It forms numerous landslides.
The varicolored cherts occur as irregular lenses, most ot them less
than 50 feet thick, composed of individual layers averaging 2 or 3 inches
in thickness of maroon red and light green siliceous chert, separated by
thin partings of shale. The chert lenses are generally much contorted or
locallv brecciated. They form rather prominent outcrops ^
The so-called "basalt" is a very dense to amygdaloidal extrusive
rock It locallv shows pillow structure, indicating that it was extruded
under water. The rock is drab green, but weathers brown ; it is massive,
hard, but not heavv, and is rather closely jointed. It is more or less
altered to greenstone, and contains numerous vemlets of calcite. it is
the most resistant rock of the_ Franciscan, as it forms prominent out-
crops ; large masses form conspicuous knobs.
In the San Rafael T^Iountains the Franciscan formation is cut by
numerous sill-like masses of 'serpentine. This was intruded as an ultra-
basic rock such as peridotite or pyroxenite, then altered to serpentine
by hvdrothermal action. The peridotite rocks have been more or less com-
pletelv altered to serpentine ; but where the original rock was pyroxenite,
manvof the crvstals of pyroxene are partially preserved. The serpentine
is dark green to bluish green and contains numerous shmy slickensided
surfaces resulting from expansion during chemical alteration. Much of
it is brecciated, and tends to form landslides. These bare, slickensided
green exposures of serpentine are generally devoid of vegetation.
22 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
In addition to the San Rafael Mountain exposures, there is a large
outcrop of serpentine at the head of San Pascual Canyon in the extreme
western Santa Ynez Mountains. This exposure is made up largely of
serpentinized pj^roxenite. Serpentine also occurs in San Lucas and Wons
Canyons as small exposures, where it seems to inject shales of the Espada
formation.
Honda Formation
The Honda formation consists of several thousand feet of clay shale
exposed only in the extreme western Santa Ynez Mountains at Canada
Honda, from 1 mile to 4 miles east of Point Pedernales.
The Honda formation is composed of dark greenish-brown clay
shale commonly containing buff-weathering calcareous concretions. It
locally contains thin layers of fine-grained sandstone of the same color.
The shale is poorly bedded and is everywhere intensely sheared. The
Honda shale either overlies or is intruded by serpentinized pyroxenite to
the north, and is unconformably overlain by the Espada formation.
A small indeterminate species of Ancella was found in the northern-
most exposure of Honda shale in San Pascual Canyon. The Honda shale
may be equivalent to the type Knoxville, but its highly sheared condition
and unconformable relationship with the Espada formation suggests that
it may be a shale member of the Franciscan. Since neither could be
proved, it is designated by the local name Honda. The type locality is on
the north side of Caiiada Honda 3 miles east of Point Pedernales.
Espada Formation
The Espada formation is a thick series of dark greenish-brown
sandy shales of predominantly Lower Cretaceous age exposed at several
areas on the north side of the Santa Ynez Mountains.
The type locality of the Espada formation is designated as the
south side of Canada Honda about 3 miles east of Point Pedernales,
where it is well exposed. Other exposures occur in Salsipuedes and El
Jaro Canyons, Nojoqui and Alisal Canyons, and in San Lucas and Wons
Canyons.
In all exposures the Espada formation is a monotonous series of
dark greenish-brown, thin-bedded silty shales and a lesser amount of
thin interbeds of hard fine-grained sandstones. Crude rhythmic bedding
is general throughout. The Espada formation is characterized by its pre-
vailing dark greenish-brown color in the shales and sandstones alike,
and by the abundant black specks of carbonaceous material in parting
planes. Locally the Espada contains thin lenses of conglomerate with
well-rounded pebbles of black chert.
The Espada formation is well indurated and is well exposed in
creek beds. It forms dark-brown exposures in hills which are invariably
covered by brush.
Unfortunately no complete section of the Espada formation is
exposed at any one locality. At the type locality at Caiiada Honda, the
base is well exposed. Here it consists of 1 foot to 5 feet of dark brown con-
glomeratic sandstone resting unconformably on highly sheared clay shale
of the Honda formation. This conglomerate is overlain by about 4000 feet
of dark greenish-brown shale and thin hard sandstone as described above.
The Espada here is unconformably overlain by lower Miocene beds.
1950] STRATIGRAPHY 23
In Sail Lucas and Wons Canyons a masimnm thickness of 6800 feet
of Espada formation is exposed, but the base of the section is in fault or
intrusive contact with serpentine, and the top is unconformably over-
lain by Eocene and middle Miocene beds. The relationship of the Espada
to the Upper Cretaceous Jalama formation is not definitely known, but
these are believed to be in contact at only two localities : at the head of
Salsipuedes Cam-on. where the relationship appears to be an uncon-
formity, and at Nojoqui Canyon, where shales of the Espada formation
are in conformable contact with hard sandstones and dark-gray shales
believed to be the Jalama formation.
The Espada formation in the Santa Ynez Mountains is generally
known as the "Knoxville" formation by geologists who have worked in
the region. In San Lucas Canyon " AuceUa" crassicollis was found in
the upper portion. This places at least part of the Espada formation in
the Lower Cretaceous, equivalent to the Paskenta formation of Sacra-
mento Yalley." Aucella" piochii was found in shales similar to the Espada
in the Casmalia Hills and in the San Rafael Mountains. This indicates
Upper Jurassic age. equivalent to the tv^pe Knoxville at Sacramento
Valley. The Espada formation is lithologically and fauiially indivisible,
but it probably contains strata equivalent to the type Knoxville (Upper
Jurassic), type Paskenta (LoAver Cretaceous), and possibly the type
Horsetown (middle Cretaceous). Because of lack of faunal control, the
formation is here designated hy the local name Espada.
Jalama Formation
The Jalama formation consists of about 4000 feet of clay shales and
sandstones of Upper Cretaceous age overlying the Espada formation and
disconformably overlain by the Eocene Anita shale. The Jalama forma-
tion is exposed in the Santa Ynez Mountains at Santa Anita and Jalama
Canyons, and at the head of Salsipuedes Canyon ; in Ytias and Xojociui
Canyons ; and on the north flank of the higher Santa Ynez Range between
Gaviota Pass and Quiota Canyon.
The type locality of the Jalama formation is designated as the divide
between Santa Anita and Bulito Canyons. Here the section is as follows :
Anita shale (middle Eocene)
Disconf ormity (?)
Gray-white to buff, hard, thick-bedded to massive well-sorted fine to
locally medium-grained saudsitone ; minor iuterbeds of sandy silt-
stone. Carries Trigonia, Baculites 300 ft.
Brown-gray massive to poorly bedded highly micaceous siltstone and silty
claystone 1000 ft.
Light buff, hard, well-bedded fine-grained sandstone ; minor interbedded
clay shale ; lower 3 feet contains abundant rounded pebbles of
porphyritic volcanic rocks and of Franciscan red and green chert.
Contains several fossil reefs of Calva steinyi, Trigonia 200 ft.
Dark-gray well-bedded clay shale with subspheroidal fracture 800 ft.
Light-brown very hard fine-grained sandstone and interbedded clay shale
as above 150 ft.
Dark gray-brown well-bedded clay shale, slightly carbonacous 400 ft.
Total thickness of Jalama formation exposed 2850 ft.
Pacifico fault
The above sequence holds true for tlie Jalama formation in Jalama
Canyon, and also in the higher Santa Ynez Range south of Alisal ranch.
24 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
The relationship to the overlying Eocene Anita shale is accordant, with
no evidence of erosion. However in the Santa Rosa Hills the Jalama is
overlain by the Anita shale and Sierra Blanca limestone with an angnlar
unconformity of about 15°. At the mouth of Ytias Creek an angular
nnconformity occurs above the Jalama, but Upper Cretaceous Trigonias
occur above the unconformity. These beds are in turn conformably
overlain by the Matilija sandstone.
At Santa Anita and Jalama Canyons the Jalama formation is highly
fossilif erous and has yielded a large fauna. Of these, the following occur
abundantly :
Pelecypoda
Calva steinyi (Hawley) (= Venus steinyi Hawley)
Glycymeris veatchii var. major Stanton
Inoceramus sp.
Mactra ashburnerii Gabb
Trigonia evansi Meek
Trigonia gibboniana Meek
Gastrapoda
Volutadernia cf. gabbi White
Cephalopoda
Baculites sp.
These forms place the Jalama formation in the Upper Cretaceous,
and correlate it with the Panoche formation of San Joaquin Valley and
possibly with the Chieo formation of Sacramento Valley.
The Eocene-Oligocene Series
The Eocene and lower Oligocene series is exposed only in the Santa
Ynez Range and consists of a very thick conformable series of marine
sandstones and shales totaling 9000 feet in the higher Santa Ynez Range
eastward from Gaviota Canyon, 6000 feet westward from Gaviota
Canyon, and thinning considerably on the north flank. It has been
mapped previously as the Tejon formation.
The Eocene-Oligocene series has been subdivided into five lithologic
units mappable throughout the western Santa Ynez Range. They are,
starting with the lowest, Anita shale, Matilija sandstone. Cozy Dell shale,
Sacate formation, and Gaviota formation. The lower Oligocene Gaviota
formation is confined to the western Santa Ynez Range. The four Eocene
units are the same lithologic units as those recognized in the eastern Santa
Ynez Range as brought out by areal mapping of the whole range. The
Anita shale of the western portion corresponds to what is called in unpub-
lished reports the Juncal formation of the eastern Santa Ynez Range, and
the Sacate formation corresponds to the ' ' Coldwater ' ' sandstone in the
eastern Santa Ynez Range. The names Matilija and Cozy Dell have been
retained. The type localities of both are in Matilija Canyon, Ventura
County. All four of these units can be traced westward to San Marcos
Pass, where all but the "Coldwater" dip under a cross-syneline, but
reappear to the west. It must be emphasized that these formations were
mapped throughout the Santa Ynez Range as lithologic, not as time units,
and that their boundaries are not everywhere contemporaneous. Some
units are difficult to differentiate locally, but their lithologic character is
fairly persistent.
As the name ' ' Coldwater ' ' is preoccupied twice in American liter-
ature, Kelley ^^ proposed the name Sacate for the ' ' Coldwater ' ' forma-
tion in the western Santa Ynez Range.
I Op. cit, p. 10.
1950] STRATIGRAPHY 25
The Sacate-Gaviota problem is one difficult to solve. The Gaviota
formation has been separated from the Saeate in the western Santa Ynez
Range because of its distinct faunal content, but it is lithologically nearly
simitar to the Saeate. The contact has been designated by a faunal break
and slieht litholoeic change at the type area of the Gaviota formation
on the south flank of the range. On the north flank the two are difficult
to separate and are therefore mapped together as Sacate-Gaviota.
Eocene at Wons Canyon
On the east side of Wons Canyon, on the east edge of Los Olivos
quadrande. about 1600 feet of Eocene sediments lie unconformably on
the Espada shale and are unconformably overlain by the upper [Monterey
Q It £3 I P
The Eocene mapped as Anita shale in "SVons Canyon consists of dark-
crrav siltstone and fine nodular sandstones ranging in thickness from less
than 1 foot to 300 feet. The Matilija comprises about 200 feet of cobble
conglomerate composed of weU-rounded cobbles of quartzite and acidic
ic^neous rocks in buff sandstone matrix, overlain by about 500 feet of
medium-grained buff sandstone which grades upward into a fine-grained
greenish-brown nodular sandstone about 500 feet thick.
[Molluscan fossils occur in the nodular sandstones near the base
of the Anita shale and also in the upper nodular sandstones of the
:\ratilija. Both localities have yielded TurriteUa uvasana, Ostrea tdnaen-
sis Gabb, and Galeodea sp.
Sierra Blanca Limestone
The Sierra Blanca limestone is well developed at the base of the
Eocene section in the San Rafael :\Iountains where it was named and
described by Xelson.i" ^^^ Keeuan.^s j^ the Santa Ynez Mountains it
occurs at onlv three localities.
The most prominent exposure of Sierra Blanca limestone occurs m
Xojoqui Canvon at Live Oak Ranch dair^-. Here it consists of about 50
feet of grav-white. hard, sandv. algal limestone. It extends up both sides
of the ean'von to the west, where it rests with a well-exposed angular
unconforniitv on the Jalama formation. This basal limestone extends up
the ridge south of the canyon for some 2 miles before it lenses out to the
west .
A small lens of Sierra Blanca limestone as much as 20 feet thick and
a quarter of a mile long occurs on the south side of Jalama Canyon 1^
miles southeast of the point where the road enters the canyon from the
north. Here it occurs in the Anita shale about 250 feet below the top. It
is of the same character as the Xojoqui Canyon exi^osure and contains'
abundant orbitoidal foraminif era.^^ . .
At Los Sauces Creek. 1 mile south of Tranquillon [Mountain, a thm
lens of Sierra Blanca limestone -o overlies buff sandstone (Eocene ?)
which rests on the Espada formation. The limestone here contains abund-
ant orbitoidal f oraminif era.
i Keenan M F The Eocene Sierra Blanca limestone at the t>-pe locality in Santo
Barbar^CoXV California: San Diego Soc. Xat. Hist. Trans., voL 7. no. 8. pp. d3-84.
^^^^" "For a description of the foraminifera see Woodring, W. P., op. cit 1930. p. 157,
P'- ^ 'a) For a description see Woodring, W. P., op. cit. 1930, p. 157.
26 SOUTHWESTERN SANTA BARBARA COUNTY [BuU. 150
The following species of orbitoidal foraminifera occur in the Sierra
Blanca limestone at Jalama Canyon :
Discocyclina psila Woodring
Aetinocyclina aster Woodring
Olicrculina or Nuinnuilites
Gypsina
On the west side of Ramajal Canyon north of Jalama Creek a sandy
phase of the Sierra Blanca limestone carries the following molluscs:
"Macrocallista" conradiana ? Gabb
Amaurellina inezana Conrad
The Sierra Blanca limestone is assigned to the middle Eocene.
Anita Shale
The Anita shale consists of about 1000 feet of clay shale lying above
the Jalama formation and below the Matilija sandstone. It has been
named and described by Kelley;^^ the type locality is on the south side
of upper Santa Anita Canyon.
The Anita shale in the western Santa Ynez Mountains consists of
dark-gray moderately well bedded clay shales and some thin beds
of greenish-brown highly micaceous sandstone. At Santa Anita Canyon
the middle portion contains thin calcareous sandstone beds with orbi-
toidal foraminifera. About 30 feet of highly foraminiferal red and green
clay shale, known as the "Poppiu shale," occurs from 200 to 400 feet
below the top of the Anita. The red and green colors are due to iron oxides,
which occur in large quantities. This colored shale commonly contains
calcite veinlets.
The Anita shale is about 1000 feet thick at Jalama and Santa Anita
Canyons, and also in the higher Santa Ynez Range. On Santa Rosa Ridge
it thins to about 300 feet, and to the north it buttresses out. It thins out
likewise in Jalama and Salsipuedes Canyons and in Caiiada Honda.
The relationship of the Anita shale to the overlying Matilija sand-
stone is accordant, although Kelley ^^ reports a disconformity. The rela-
tionship of the Anita shale to the underlying Jalama formation appears
to be conformable, but in the northerly exposures the Anita rests uncon-
formably on the Jalama or older formations. The iron oxides in the
Poppin shale were probably derived from basic rocks of the Franciscan
to the north. The Poppin shale and Sierra Blanca limestone in Jalama
Canyon occur at about the same horizon in the Anita shale, and it is
possible that this horizon may be the base of the Eocene section of the
Santa Ynez Range.
The upper portion of the Anita shale, especially the Poppin shale,
has yielded a large foraminiferal f auna.^^ On the basis of this fauna, and
of the occurrence of the Sierra Blanca limestone at about the same horizon,
the upper Anita shale is assigned to upper middle Eocene. The lower
portion of the Anita shale has yielded no foraminifera, and its age is
therefore unknown. It may be middle or lower Eocene or Upper Cre-
taceous.
Matilija Sandstone
The Matilija sandstone in the w^estern Santa Ynez Mountains con-
sists of about 1000 feet of sandstone lying conformably between the Anita
shale below and the Cozy Dell shale above.
21 Op. cit, p. 6.
22 0p. cit, p. 7.
23 For listing, see Kelley, F. R., op. cit., p. 8.
J^950] STRATIGRAPHY 27
The Matilija sandstone attains a maximum thickness of about 1200
feet in the higher Santa Ynez Kan?e east of Las Cruces, but thins down
to about 400 feet at Refugio Pass, then thickens eastward to 2000 feet at
Santa Ynez Peak. Between Las Cruces and Jalama Canyon the Matilija
is from 500 to 1000 feet thick. Northward it thins rapidly, being less than
300 feet thick in the Santa Rosa Hills and in areas to the west. Where the
underlying Anita shale buttresses out the Matilija sand rests unconform-
ably on the Cretaceous or Franciscan. o- ^ . ^i • i
The ^latilija is made up of a succession of beds up to 2o feet thick
of massive, medium-grained fairly hard bluish-white sandstone which
weathers buff. The sandstone beds are separated by thm partings ot
micaceous sandv shale. The basal portion locally contains an algal reet
and some rounded cobbles of quartzite and granitic rocks.
The Alatilija sandstone is highly resistant to erosion and forms the
highest strike ridges of the western Santa Ynez Mountains. Most of it
supports brush. . , . n o, ^ t^ tt-h
At the Gaviotito-Santa Anita divide and also m the Santa Rosa Hiiis
the Matilija has yielded the following diagnostic moUuscs :
Pelecypoda
Macrocallista horuii Gabb
Gari horuii (Gabb)
Xemocardium linteum (Conrad)
Pitar uvasanus (Conrad)
Schedocardia ef. brewerii (Gabb)
Gastropoda
Amaurellina aff. moragai (Stewart)
Ectinocbilus canalifer supra plica tus (Gabb)
Ficopsis horuii (Gabb)
Ficopsis remondii (Gabb)
Ficus mamillatus ((iabbj
Galeodea susanae (Schenck)
Olequahia ef. horuii (Gabb)
Seraphs erratica Cooper
Turritella uvasana Conrad
Turritella applinae Hanna
Turritella scrippseusis M. A. Hanna
This fauna places the Matilija sandstone in early upper Eocene, or
in the so-called moUuscan " Transition stage" of Clark and Vokes.-
Cozy Dell Shale
In the western Santa Ynez Range the Cozy DeU shale consists of
about 700 feet of well-bedded shale lying conformably on the Matilija
sandstone and grading upward into the Sacate formation
The Cozy DeU shale maintains a fairly uniform thickness ot about
700 feet throughout the western Santa Ynez Mountains, although it is
somewhat thicker in the higher Santa Ynez Range. „ ^ -, , -, , ^
The lower half of the Cozv Dell shale consists of well-bedded, but
easily weathered grav clay shales with spheroidal fracture. This portion
contains one, or loeallv several, thin beds of hard greenish sandstone IbO
feet from the base. The upper half of the Cozy Dell consists of the same
tvpe of shale but with two members of thin-bedded, slightly siliceous
harder brown clav shales which weather pale gray and form prominent
exposures The upper member locally carries gray limestone nodules
that weather vellow. The Cozy Dell shale grades upward through a series
of thin sandstone interbeds into the overhdng Sacate sandstone.
^cTark, B. K. and Yokes. H. E., Summary of marine Eocene sequence of western
North America : Geol. Soc. America Bull., vol. 47, no. 6, pp. 80I-8 < 8, I9rft>.
28 SOUTH WESTERN SANTA BARBARA COUNTY [Bull. 150
The Cozy Dell sliale is nou-resistant to erosion, forming saddles
across ridges or amphitheaters in canyons between more resistant Matilija
and Saeate sandstones. It forms grassy slopes.
The lower half of the Cozy Dell shale has yielded an upper Eocene
foraminiferal fauna. The species listed by Kelley ^^ correlate it with
Laiming's zone A-2.-" The upper half of the Cozy Dell shale has not
yielded a diagnostic fauna.
Saeate ("Coldwater") Formation
In the western Santa Ynez Mountains the Saeate (or "Coldwater")
formation consists of about 1000 feet of interbedded sandstone and shale
conformable between the Cozy Dell shale below and the Gaviota forma-
tion above. The type localit}^ of the Saeate formation is at Saeate Can-
yon ; this section is described by Kelley .^^
The Saeate formation consists of sandstone and shale interbedded
in about equal amounts. The sandstone beds are fine to medium grained,
hard, well bedded to massive, highly micaceous, bluish gray when fresh,
but weather to buff. The hard thin beds form large slabs. The inter-
bedded shales are gray, w^ell bedded to laminated, highly micaceous,
sparingly foraminiferal. Thin layers of hard brown conglomerate occur
locally, with rounded pebbles of porphyritic igneous rock and some Fran-
ciscan red cherts in a hard sandstone matrix commonly containing 03'ster
shells. The uppermost 200 to 500 feet of Saeate on the south flank of the
range consists of brown slightly organic massive to w^ell-bedded clay
shale. On the south flank the Saeate formation is well exposed. Here
the hard sandstone beds form prominent ledges.
Both the upper and lower contacts of the Saeate formation are gra-
dational and thus difficult to map. The base is placed at the first appear-
ance of numerous sandstone beds w^hieli form a prominent topographic
break. West of Las Cruces the top is placed at the contact between the
organic shale member below, which carries an Eocene fauna, and the
massive, poorly exposed siltstone above, which carries a Refugian fauna
and is therefore assigned to the Gaviota formation. East of Gaviota
Canyon this siltstone grades laterally into sandstone, so that all of the
500 feet of shale there underlying the Gaviota sandstone is mapped
with the Saeate.
In the Santa Rosa Hills and San Julian Ranch the Saeate is pre-
dominantly shale with thin sandstone interbeds. It grades upward into
the Gaviota formation which is mainly sandstone, but because of poor
exposures and lack of faunal control, the contact has not been determined.
The formations are therefore mapped together as Sacate-Gaviota.
The Saeate formation carries the following megafossils : '^^
Pelecypoda
Venericardia cf. hornii (Gabb)
Ostrea idriaeusis Gabb
Gastropoda
Amaurellina sp.
Cypraea sp.
Turritella variata var. julian.-i Merriam
^ Op. cit., p. 11.
28 Kelley, F. R., op. cit, p. 10.
27 Op. cit, pp. 10-12.
28 Kelley, P. R., op. cit, p. 13.
1950] STRATIGRAPHY 29
This meager fauna and the stratigraphic position of the Sacate
formation place it in uppermost Eocene, equivalent to Clark and Vokes'
niolluscan "Tejon stage." The Sacate has yielded a foraminiferal fauna
correlative with Laiming's zone A-1.
Gaviota Formation
The Gaviota formation consists of about 1600 feet of thick-bedded
sandstone and siitstone conformable between the Sacate formation below
and the Alegria sandstone above. The type area of the Gaviota forma-
tion is on the south slope of the Santa Ynez Range between Gaviota and
Bulito Canyons ; the type locality is at Caiiada de Santa Anita.-''
The type Gaviota formation west of Las Cruces is about 1600 feet
thick and consists of three members, each about 500 feet thick. The lower
member is a massive soft gray siitstone; the middle member is light
buff, thick-bedded, well-sorted fine- to medium-grained concretionary
sandstone; the upper member is gray sandy siitstone with some inter-
bedded fine-grained sandstone. On the south flank of the range east of
Gaviota Canyon, and on the north flank of the Santa Ynez Mountains,
the upper member grades into sandstone; east of Tajiguas Canyon the
lower member also becomes sandstone. The sandstones of the Gaviota
formation are highly resistant to weathering and thus form prominent
brush-covered outcrops. The siitstone members are easily weathered to
low grassy slopes.
The Gaviota formation is of shallow marine origin, and the sand-
stones are richly fossiliferous. A prominent fossil reef composed largely
of Crassatella collina occurs at the top of the middle member near Las
Cruces and near the San Julian ranch house. Foraminif era are abundant
in the siitstone members.
The f ollo-s^-ing molluscs are abundant in the Gaviota formation :
Pelecypoda
Crassatella collina Conrad
Ostrea tayloriana Gabb
Pecten (Cblamys) yneziana Arnold
Tivela inezana Conrad
"Cardium brewerii" Gabb (large, of Arnold & Anderson 1907)
Yenericardia hornii Gabb
Gastropoda
Turritella variata Conrad
Ficus gesteri Wagner & Schilling
Siphonalia merriami Wagner & Schilling
Venericardia liornii has been regarded as an Eocene marker, but the
rest of the molluscan fauna is unlike that of any other Eocene fauna of
California. The foraminiferal fauna is also unlike that of the California
Eocene. Because of the strange fauna Schenck and Kleinpell^" desig-
nate the Gaviota formation at the type locality as the type "Refugian
stage," which they assign to lower Oligocene.
Bed by bed mapping of the Gaviota formation on the south slope
of the Santa Ynez Range from Gaviota Canyon eastward to San jVIarcos
Pass shows that the upper portion grades laterally eastward through
coarse littoral sands into the basal pink conglomerate and red beds of the
lower part of the Sespe formation, the contact becoming successively
lower from west to east. The lower portion of the Gaviota sandstone
»Efflnger, W. L., Gaviota formation of Santa Barbara County, California: Geol.
Soc. America Proc. 1935, pp. 351-352, 1936.
^ Op. cit
30 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
grades eastward into the upper Sacate ("Coldwater") sandstone from
which it is not differentiated.
Alegria Formation
The Alegria formation is the marine facias of the continental Sespe
formation in Gaviota and Point Conception ((nadrano-les. The Alegria
consists of about 1200 feet of sandstone and a minor amount of siltstone
lying conformably above the Gaviota formation and disconformably
below the Vaqueros formation.
The Alegria formation, generally known as "marine Sespe," is
developed only on the south flank of the Santa Ynez Range between a
point 4 miles north of Point Conception and Capitan Canyon. The type
locality is designated as the ridge east of Canada de Santa Anita, where
the section is as follows :
Vaqueros sandstone and conglomerate.
Disconformity
G Buff, laminated friable fine- to medium-grained sandstone 250'
F Poorly exposed soft greenish siltstone. Thickens eastward, lenses
out westward 10'
E Gray-white to buff, friable medium- to fine-grained sandstone.
Becomes pebbly eastward 110'
D Soft light gray-brown poorly to well-bedded siltstone and thin
layers of very fine sand 150'
C Light-buff friable massive to thick-bedded medium-grained sand-
stone ; lower 90 feet gray, coarse grained, and contains several
oyster reefs 2.30'
B Soft greenish-brown silty to sandy clay shale 80'
A Light-buff to gray friable massive sandstone with few small
rounded pebbles 180'
Total 1010'
Conformity
Gaviota siltstone
These members vary along the strike in lithology and thickness, but
the above type of lithology is characteristic of the Alegria formation
throughout its extent. It is made up predominantly of medium- to coarse-
grained, thick-bedded sandstones which form prominent exposures. They
are generally fossiliferous and are shallow-marine littoral deposits. In
the most westerlj^ exposure siltstone members B and D become somewhat
brown and organic and weather pale gray. Eastward from Alegria
Canyon member G thickens to more than 600 feet. From Agua Caliente
Canyon the Alegria formation grades laterally eastward into the non-
marine Sespe formation, with the first red clays appearing in member G
at Gaviota Canyon, but green clays of possible nonmarine origin persist
in this member as far west as Cuarta Canyon. Eastward from Gaviota
Canyon, red clays appear progressively lower in the section, until at
Capitan Canyon they occur throughout the section, which apparently is
all nonmarine. The standstones retain their buff color even where they
become unfossiliferous and supposedly nonmarine, so that it is difficult
to determine just where the Alegria formation grades into Sespe.
Bailey ^^ extends the Sespe nonmarine beds as far west as Santa Anita
Canyon. The contact between the predominantly marine Alegria forma-
tion and the predominantly nonmarine Sespe is shown approximately
on the geologic map.
SI Bailey, T. L., Origin and migration of oil into Sespe red beds, California : Am.
Assoc. Petroleum Geologists Bull., vol. 31, no. 11, pp. 1913-1935, 1947.
1950] STRATIGRAPHY 31
The Alegria formation lies conformably upon the upper siltstone
member of the Gaviota formation. Eastward from Arroyo Hondo, where
the upper Gaviota becomes sandstone, the two formations are difficult to
differentiate. The relationship of the Alegria to the overlying Vaqneros is
an unconformity, as indicated by gradual overlap of successive beds of
the former from east to west ; west of Cojo Canyon there is an angular
discordance of about 15°.
At Bulito Canyon the top of member C of the Alegria carries the
following molluscan species :
Ostrea tayloriana Gabb
Pecten (Chlamys) yueziana Arnold
Tivela inezana Conrad
Turritella variata Conrad
This fauna is the same as that of the underlying Gaviota formation,
and thus places the Alegria in the Refugian stage of the Oligocene.
Kleinpell "- reports a Zemorrian microfauna from green siltstone west of
Gaviota Canyon, which is believed to be member F of the Alegria
formation.
Sespe Formation
The Sespe formation in the western Santa Ynez Mountains is a
series of continental sandstones, clays, and conglomerate lying above the
Gaviota or older formations and below the Vaqneros sandstone.
The Sespe formation is best developed on the south slope of the
Santa Ynez Range in the vicinity of Capitan and Corral Canyons. Here
it consists of about 2200 feet of pinkish-gray to buff friable laminated
sandstone interbedded with red and green clays and silts. Westward
along the strike the prevailing pink color of the sandstones gives way to
gray and buff. Only the fine sediments retain their red color. The thick
basal conglomerate of the Sespe in the Santa Barbara-Goleta area is not
present in the area mapped. Between Refugio and Gaviota Canyons
progressively lower beds of the Sespe formation grade laterally west-
ward into the marine Alegria formation.
In the Santa Rosa Hills and eastward to Quiota Canyon the Sespe
formation averages about 500 feet in thickness and consists of coarse
basal green conglomerate composed almost entirely of Franciscan debris,
grading upward into red and green friable sandstone and interbedded
variegated clays and silts. Here the Sespe lies on Gaviota or older forma-
tions with a great regional unconformity, but grades upward into
Vaqneros marine beds. In this area the Sespe is of Zemorrian age (lower
Miocene) as it unconformably overlies the Gaviota formation of Refugian
age, and in part grades into marine Vaqneros in the western Santa Rosa
Hills. On San Julian ranch, however, the Sespe is overlapped on the
northwest by the marine Vaqneros conglomerate.
Vaqueros Formation
The Vaqueros formation in the western Santa Ynez Mountains con-
sists of as much as 600 feet of marine sandstone and conglomerate of
Zemorrian age (lower Miocene) lying above the Sespe, Alegria, or older
formations and conformably below the Rincon shale.
On the south slope of the range the Vaqueros sandstone forms a very
prominent and continuous brush-covered ledge from Bixby Canyon,
^ Schenck and Kleinpell, op. cit.
32 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
north of Government Point, for some 27 miles eastward across Point
Conception and Gaviota quadrangles. Between Canada del Capitan and
Arroyo Hondo the Vaqneros consists of about 200 feet of light-graj^,
friable to hard calcareous, cross-bedded medium- to coarse-grained sand-
stone. Westward the lower portion becomes pebble conglomerate. At
Gaviota Canyon the Vaqueros thins down to 25 feet, but thickens again
toward the west and averages about 75 feet west of Alegria Canyon.
The Vaqueros formation is best developed on the north flank of the
Santa Ynez Mountains in the vicinity of Nojoqui and Alisal Canyons.
Here it is about 600 feet in maximum thickness and consists of light
greenish brown concretionary fine- to medium-grained sandstones inter-
bedded with massive gray siltstones. In this area the Vaqueros grades
downward into the underlying Sespe and upward into the Rincon shale.
In San Julian Valley and westward to the Tranquillon Mountain
area, the Vaqueros consists of as much as 300 feet of buff sandstone grad-
ing doAvnward into greenish-brown fossiliferous, cross-bedded basal con-
glomerate composed almost entirely of Franciscan debris.
On the south slope of the Santa Ynez Range, eastward from Gaviota
Canyon, the Vaqueros sandstone lies with a sharp, possibly disconform-
able, contact on the Sespe, but no conclusive evidence of an unconformity
is indicated here. Farther west, the Vaqueros gradually overlaps the
upper members of the Alegria, and west of Co jo Canyon this becomes
an angular unconformity. A great regional unconformity becomes
strongly developed throughout the northwestern part of the Santa Ynez
Mountains, where the Vaqueros overlaps the eroded edges of the Gaviota
and older formations which had previousl}^ been compressed into broad
folds trending slightly north of west. A nearly similar condition holds
true for the unconformity at the base of the Zemorrian Sespe in the
Nojoqui- Alisal area, which was probably developed at the same time or
slightly earlier.
The Vaqueros formation contains the following molluscan species
in the western Santa Ynez Mountains :
Pelecypoda
Ostrea eldridgei Arnold (large)
Pecten (Pecteu) vanvlecki Arnold
Pecten (Lyropecten) magnolia Conrad
Pecten ( Chlamys ) sespeensis Arnold
Traehycardium vaquerosensis Arnold
Macoma nasuta (Conrad)
Gastropoda
Turritella inezana Conrad
Turritella inezana var. altacorona
Rapana vaquerosensis (Arnold)
Pecten (Lyropecten) magnolia and Turritella inezana are abundant
in the basal conglomerate throughout the northwestern Santa Ynez
Mountains. The other species occur more abundantly in the Vagueros
sandstone.
The above fauna places the Vaqueros formation of the Santa Ynez
Mountains in the Zemorrian stage, lower Miocene.
DIVISION OF MINES
BULLKTIN 150, PLATE 10
A VIEW WEST ALONG SANTA YNEZ RANGE FROM HEAD
OF JALAMA CANYON
i^chenck. lii',1.
B VIEW EAST ALONG WESTERN SANTA YNEZ MOUNTAINS
FROM HEAD OF EL BULTTO CANYON
Tvpe exposure of Jalanm formation showing fossiliferous .f ""intones at left of
camonrSpper shale member and sandstone at right. Photo Inj H. G. Schencl, IS)!.
-1396G
DIVISION OF MINES
BULLETIN 150, I'LATE 11
A, VIEW WEST ACROSS CANADA DEL GATO ON SOUTH FLANK
OF SANTA YNEZ MOUNTAINS
Matilija sandstone beds at right, oveiiain by Cozy Dell shale at middle, in turn
overlain bv Sacate sandstone, which forms peak at left of picture. Photo by
H. G. Schcnck, 19.',1.
B, VIEW NORTHEAST FROM GAVIOTA SHOWING OUTCROPS
OF ALEGRIA SANDSTONE
Skyline ridge formed by Gaviota sandstone.
DIVISION OF MINES
BULLETIN 150, PLATE 12
^1, ANGULAR UXCONFOPailTY BETWEEN EOCENE FOSSILIFEROUS SAND-
STONE (MATILI.IA) AND CRETACEOUS SHALE (JALAMA?)
Beds dip southwest ; 3.3 miles south of Buellton, 0.3 mile west of Nojoqui Creek.
B, VIEW WEST ACROSS NOJOQUI CANYON 2.5 MILES
SOUTH OF BUELLTON
Light-colored beds on high bluffs are Vaqueros sandstone, underlain by "Sespe"
conglomerate and Cozy Dell shale, which form grassy slopes. Lower brush-covered
hills are Jalama? formation.
DIVISION OF MINES
BULLETIN 150, PI>ATE ]?,
m^i^
•1 •'..«**<"
-/
.' 'ffi^»
.V .
^-
*» ,
.•\ V
.<
*»j^
v OsJ
^'
-a^'J^i'
.4. VAQUEROS CONGLOMERATE IN RAMAJAL CANYON
0.7 mile north of Jalama Creek, 4.6 miles ea.st of mouth. Conglomerate contains
abundant Pecten magnolia and Turritella inesana. Bed dips 85° N. (to right).
B, STEEPLY DIPPING LIMESTONE BED
In Member B, lower Monterey shale, east of Alegria Canyon.
1950] STRATIGRAPHY 33
Rincon Claystone
The Rincon ela.ystone is about 1500 feet thick and lies conformably
above the Vaqneros sandstone in the Santa Ynez Mountains.
On the south flank of the range the Rincon forms a continuous
exposure adjacent on the south to the Vaqneros sandstone across Point
Conception and Gaviota quadrangles. It is also well exposed through
Quiota, Alisal, and Nojocjui Canyons, in the Santa Rosa Hills, San
Julian and Jalama Canyons, and in the Tranquillon Mountain area.
The Rincon lies conformably on the Vaqneros everyw'here except on
Tranquillon Mountain ridge, -where it lies unconformably on the Espada
formation, the Vaqneros having buttressed out. The relationship with the
overlying Monterey is conformable except in the northwestern Santa
Ynez Mountains, where it is unconformable.
The Rincon formation at all exposures is made up of brown-gray
poorly bedded to massive clay shale with spheroidal fracture ; yellow-
weathering calcareous concretions are common. In the more northerly
exposures in San Julian Valley and at Tranquillon Ridge the Rincon
claystone is somewhat hard and weathers nearly white, probably because
of its siliceous or bentonitic material content. The Rincon readily weath-
ers into a clayey adobe soil which forms low grass-covered slopes, in
marked contrast to the brush-covered Vaqneros sandstone outcrops.
The lower third of the Rincon claystone carries an upper Zemorrian
(lower Miocene) foraminiferal fauna. The upper two-thirds of the Rin-
con carries a Saucesian (upper lower Miocene) foraminiferal fauna.
Lospe Formation
The Vaqueros-Rincon formations are not known to occur in the
Santa Maria Basin, but may be represented by the lower Miocene (?)
Lospe formation, consisting of 2700 feet of terrestrial reddish and green-
ish sediments and lenses of white indurated tuff, exposed in the Casmalia
Hills. This section starts with a basal conglomerate of debris derived
from the underlying Franciscan, and grades upward through bedded
sandstones into gypsiferous mudstone which is overlain b}" the Relizian
Point Sal formation.
The Lospe formation underlies Casmalia and Orcutt oil fields, and
may underlie Burton j\Iesa and Lompoc oil field ; for several wells pene-
trated a thin series of gray and reddish sandstones and tuff'aceous ( '?)
rocks betAveen the Monterey shale and Franciscan, which may be either
the Lospe formation or the equivalent of the Tranquillon volcanics or
Obispo tuff.
Tranquillon Volcanics
The Tranquillon volcanics are a local phase of the Obispo tuff of
San Luis Obispo County, and are composed of as much as 1200 feet of
rhj'olite, agglomerate, and ash exposed on Tranquillon Mountain ridge
and vicinity. Here this volcanic series lies conformably below the ]\Ion-
terey shale and unconformably above Rincon and older formations. It
is generally regarded as the basal member of the Monterey formation,
but since it is a rock unit distinct from any other in this area, it is treated
as a formation. The type locality is designated as the ridge west of
Caiiada del Rodeo.
The Tranquillon volcanics are made up mainly of a large rhyolite
flow which forms Tranquillon Peak and the large dip-slope on the south
3 — 13966
34 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
side of this same ridge. The rhyolite is buff colored, dense to slightly
porphyritic, and shows prominent fiow-structure. The flow lenses out
east and west of the ridge, and is replaced by rhyolite agglomerate and
tuff at Point Pedernales and in the vicinity of Jolloru Canyon. The
rhyolite may have erupted along the ridge immediately north of Tran-
quillon Peak or from the exposure north of Canada Honda Creek, but
its source is not definitely known.
East of Jolloru Creek the Tranquillon volcanics lens out, but reap-
pear locally in other parts of the western Santa Ynez Mountains. At
Bixby Canyon 3 miles north of Government Point they appear as a lens
up to 50 feet thick of rhyolite tuff-breccia at the base of the Monterey
shale. Farther east they are represented by local occurrences of bentonite
at this horizon.
Other exposures of Tranquillon volcanics occur along the Santa
Ynez River in the vicinity of the Santa Rita Hills, comprising basalt,
basaltic agglomerate, tuff, and bentonite totaling 500 feet in maximum
thickness. About 690 feet of basalt was drilled through in Tidewater
Associated Oil Co. No. "Leonis" 1 well.
On the south side of the Santa Ynez River south of Solvang is a
quarry in which about 75 feet of Tranquillon formation, composed of
sandstone, hard indurated tuff, and algal limestone, is exposed.
At Quiota Canyon the Tranquillon formation is represented by
about 30 feet of pumice tuff and bentonite on the hill southwest of the
canyon. On the east side of this canyon is about 60 feet of medium-grained
buff sandstone with a 5-foot layer of bentonite and pumice tuff near the
middle.
In El Jaro Canyon below the juncture with Amoles Creek is a layer
of limestone about 50 feet thick, at the base of the Monterey shale. The
basal portion contains tuff, sandstone, and conglomerate which may be
equivalent to the Tranquillon volcanics.
The Tranquillon formation is upper Saucesian in age (upper lower
Miocene). This is indicated by the presence of upper Saucesian fora-
minifera at Capitan Beach, in the upper Rincon shale underlying the
Tranquillon bentonite bed, and also in the overlying basal Monterey
shale. On the basis of microfauna the Tranquillon volcanics definitely
correlate with the Obispo tuff at the mouth of Cuyama River. On the
east side of Quiota Canyon the sandstone of the Tranquillon formation
carries the following molluscs :
Pecten (Amusium) lompocensis Arnold
Pecten (Lyropecten) estrellanus (Conrad)
Pecten (Lyropecten) magnolia Conrad
Turritella ocoyana Conrad
Turritella temblorensis Wiedey
Monterey Shale
The term Monterey shale, as used in this report, includes all the sedi-
ments lying above the Rincon shale (and above the Tranquillon volcanics
where present), and below the Sisquoc formation. The Monterey shale
as herein used is the same as the Modelo formation of the Ventura Basin.
The Monterey shale is made up of predominantly siliceous shales ranging
in age from uppermost Saucesian to lower Delmontian of the Miocene.
The Monterey shale herein includes the Relizian Point Sal formation of
the northern Santa Maria Basin as mapped by Woodring and others,^^
«» Op. cit, 1944.
1950] STRATIGRAPHY 35
as this unit loses its identity as a formation and becomes inseparable from
the Monterey shale in the Santa Ynez Mountains and southern Santa
Maria Basin.
Throughout the area mapped the Monterey shale is divisible into two
lithologie members, lower and upper. The lower Monterey is characterized
by a mixture of clayey shales, siliceous shales, and limestones, and the
upper Monterey by siliceous shales. The upper ]\Ionterey as used in this
report corresponds to the "Middle and Upper member" of the Monterey
as mapped ^^ in the northern Santa Maria Basin, and the lower Monterey
to the "Lower member" of the Monterey and the Point Sal formation.
In the Santa Ynez Mountains the Monterey shale averages about
1700 feet in thickness, and both members are well exposed. In the portion
of the Santa ]\Iaria Basin mapped the Monterey shale is present nearly
throughout, but is buried by later formations except in Burton Mesa and
eastern Purisima Hills, where the upper member crops out. The Monterey
shale ranges from 1800 to 4500 feet in thickness in the Santa Maria Basin.
Santa Ynez Mountains. The Monterey shale is well exposed in the
Santa Ynez ]\Iountains where it ranges from 1200 to 2000 feet in thickness.
On the south flank of the range, and in the Santa Rosa Hills, the Monterey
lies conformably on the Rincon. However, elsewhere in the Santa Ynez
Mountains, especially throughout the northwestern portion, the Monterey
shale, or the Tranquillon volcanics where present, lie unconformably on
the eroded surface of older formations ranging from Rincon to Fran-
ciscan. The relationship of the Monterey to the overlying Sisquoc is
conformable except for a local disconf ormity developed in the Santa Rita
Hills and on the coast west of Gaviota.
The Monterey shale is well exposed on the south flank of the Santa
Ynez Range west of Gaviota. Here the section is divisible into five litho-
logic members, each with a distinct microfauna.
The sequence shown in the section (page 36) holds true for most of
the Santa Ynez ■Mountains, but because of structural complexity and
poor exposures the various members cannot everywhere be mapped.
In the Santa Ynez IMountains the lower Monterey shale averages
about 800 feet in thickness, and attains its maximum of 1800 feet at San
Pascual Canyon. It locally buttresses out against older formations in
Salsipuedes Canyon, and also at San Lucas Canyon. The lower Monterey
consists of a heterogeneous series of well-bedded shales of various t5T)es,
composed of soft phosphatie shales, fissile organic shales, impure diato-
mite and siliceous shales, and interbedded limestone beds. Thin layers of
volcanic ash are common. Layers of clay shale and siltstone are common
in the lower (Relizian) portion. From Cailada de la Vina westward the
lower Mohnian portion grades laterally into cherty shale which is mapped
with the upper ]\Ionterey. In the vicinity of Tranquillon Mountain the
entire lower ]\Ionterey shale is largely composed of cherty shale which is
difficult to separate from the upper Monterey.
The lower Monterey is weakly resistant to erosion but more resistant
than the underlying Rincon. It tends to form landslides. The lower Mon-
terey weathers to a deep heavy adobe soil which supports only grasses
and annual herbs.
Throughout most of the Santa Ynez Mountains the upper Monterey
shale averages about 950 feet, but it thickens to more than 3000 feet at
** Woodring, W. P.. and others, op. cit., 1944.
36
SOUTHWESTERN SANTA BARBARA COUNTY
[Bull. 150
Monterey shale section exposed on south flank of S!anta Ynez Range
hetireen Cojo and (lariola Canijons.
Sisquoc shale with basal sand and chert conglomerate east of Sacate Canyon.
Disconformity
F Hard laminated brown platy porcelaneous shale which
weathers wliite. Carries lenses of chert conglomerate
east of Cuarta Canyon. Ahnndant diatoms, sparse fo-
raminifera. Delmontian stage, upper INIiocene 100'-200'
Upper Monterey
E Hard laminated brittle opaline cherty .shales grading
into above member. Contains layers of dark chalcedonic
chert westward from Gato Canyon. Sparse foraminif-
era. Upper Mohnian stage, upper Miocene 2r)0'-.550'
Lower Monterey
Conformity
Rincon clay shale
I) Soft, laminated fissile diatomaceous .shales; phosphatic
shales ; occasional thin limestones ; minor porcelaneous
and cherty shales. Abundant foraminifera. Lower
Mohnian stage, upper Miocene IHO'-.SOO'
C Hard white limestone and interbedded thin strata of
soft diatomaceous shale, minor amounts of phosphatic
shale, and laminated siliceous shale. Abundant foram-
inifera, especially Valvulineria, califoniica and Sipho-
generinu coUonii. Luisian stage, middle Miocene
150'-180'
B Soft ))uiif-weathering bedded to massive siltstone, silty
siliceous shale, and buff-weathering limestone beds.
Foraminifera abundant locally. Relizian and upper-
most S.uicesian stages, middle ^Miocene 160'-4B0'
A Bentonite, equivalent to Tranquillon volcanics O'-IO'
Aggregate thickness 1010'-1440'
1950] STRATIGRAPHY 37
San Lucas Canyon. On the south flank eastward from Gato Canyon and
on the north flank eastward from Solvang the upper Monterey is char-
acterized by hard, browu. platy porcelaueous shale. On both flanks of the
range this grades westward into opaline clierty shales, which in the
extreme western Santa Ynez Range contain numerous layers of heavy
contorted chalcedonic chert.
Phases of pure punky laminated diatomite are locally interbedded
in the cherty shale of the upper Monterey at Salsipuedes. San Miguelito,
and Jalama Canyons. Most of these occur toward the top. but at Salsi-
puedes Canyon some occur far down the section. The 1000 feet of pure
laminated diatomite overlying the Monterey siliceous shales at the
Lompoc quarries and vicinity has been mapped as the lower Sisquoc for-
mation. It is of Delmoutian (upper Miocene) age. At the beach west of
Ga^dota Canyon are several lenses as much as 75 feet thick of well-bedded
conglomerate in member F of the ]\Ionterey and at the base of the Sisquoc.
This conglomerate is made up of unsorted angular to sub-rounded cob-
bles and pebbles composed mainly of ]\Ionterey cherty shale ; there are
also some pebbles of quartzite. porphyries, sandstone, etc. The matrix is
a tar-soaked cross-bedded sand made up largely of quartz grains. The
occurrence is remarkable, as at this locality the Monterey is made up of
porcelaueous shale, and no clierty shale is present. The conglomerate is
apparently the result of some local uplift and erosion at the end of depo-
sition of the upper Monterey shale.
The upper Monterey siliceous shale is rather strongly resistant to
erosion. Since the shales are hard but closely fractured they form high
but rounded hills and narrow, steep-sided canyons. They develop little
soil and generally support brush or oak timber, in contrast to the lower
Monterey which forms open gras.slands.
Santa Maria Basin. The Monterey shale underlies nearly all of the
Santa Maria Basin mapped, but is generally concealed by younger forma-
tions. Only in Burton ]\Iesa and eastern Purisima Hills the upper Mon-
terey is exposed. However, data on the distribution and thickness of the
Monterey shale where concealed have been furnished from well-logs.
On Burton ]\Iesa and the south flank of the Purisima Hills the ]Mon-
terey shale averages slightly less than 2000 feet, but thickens northward
to some -toOO feet on the north flank of the Purisima Hills and perhaps
under Los Alamos Valley and upper Santa Ynez Valley. Throughout
most of the Burton Mesa, Lompoc Valley, and Purisima Hills the Mon-
terey is luiderlain by Franciscan or Espada formations, except for some
local intei'^-eniug tuffaceous sediments thought to be the Lospe formation.
This condition indicates a great regional unconformity at the base of the
Monterey shale. The Monterey is conformably overlain by the Sisquoc
diatomite in the Santa ]\Iaria Ba.sin. except under the San Rafael foot-
hills, where it is successively truncated northeastward by the Sisquoc. In
the northeastern portion it is completely overlapped.
Both members of the Monterey shale are present in the Santa ]\Iaria
Basin and their lithologic character is the same as in the Santa Ynez
Mountains. The exposures of upper Monterey in Burton Mesa and east-
ern Purisima Hills consist of close-fract>ired cherty shale grading
upward into porcelaueous platy shale.
38
SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
AGE
THICK.
DESCRIPTION
Recent
O-iOO
Silts ond gravels
0-100
G ravel s
E 3200+
Diatomaceous siltstone.
Clay shale or
diatomaceous mudstone.
Thin-bedded clay shale or
laminatffd diatomite.
1000-
3000'
Porcela neous arid cherty
Siliceous shales.
Organic shales and
thin limestones.
^0-1200
Rhyolite and basalt lava,
agalomerate, tuff, bentonite.
; 0-1700
CI ay stone.
r 0-900'
Sandstone i conglonnerate.
Pink to buff sandstone and
red and green siltstone.
Gray to buff marine
sondstone.
Fossiliferous buff
sandstone and siltstone.
Buff sandstone and
clay shale.
Brown clau ehale.
Buff arkosic sandstone.
Dork gray cloy shale.
Algol llmettone lent.
Buff finegrained sandstone.
Groy siltstone.
Buff sandstones and
gray clay shales.
Cretaceous
Jurassic Upper
Dark greenish brown
carbonaceous shales and
thin sandstones.
Basal pebblij sandstone.
Dark greenish brown
nodular claystone.
Hard green sandstone and
black shale.
Serpentine intrusions.
Figure 2. Stratigraphic column, western Santa Ynez Mountains.
1950]
STRATIGRAPHY
39
AGE
FORMATION LITHOLOGY THICK
DESCRIPTION
Recent
Dune Sond
SO'
Wind blown sand
Alluvium
O-ISO'
Silt, sond. grovel
upper
Te r r a ces
O-I50'
Gravel, iond.
Orcutt
O-300
Sond, bosol grovel.
Pleistocene
lower
Paso Robles
upper
Cobble and boulder grovel.
Shale-pebble grovel, silt.
Pebbly gray silt, clay, sand.
Basal marl.
Careaga
O-80O'
Pliocene ,
— ? —
middle
Fox en
Buff sand, pebbly sand.
Fine yellow sond.
0-900'
Gray cloystone
lower
Sisquoc
upper
M iocene
Monterey
Diotomite and clQustone.
Diatomaceous claystone
Lominoted diotomite ond
diatomaceous shale.
middle
lower
Lospe ?
Porcelaneojs siliceous ihote
Chertti Siliceous shale.
Organic shales ond
thin limestones.
0-300
Reddiih sandstone, tuff
Cretaceous Lower
Espada or
"Knoxville'
Jurassic Upper
Franciscan
Dark greenish brown
cloy shale and sandstone.
Ill III I" ii> III
Hord green sandstone.
Sheared black clay stone.
Varicolored cherts.
Massive to amyqdaloidal
basalts.
Numerous serpentine
intrusions.
Figure 3. Stratigraphic column, southern Santa Maria Basin.
40 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Lithologic Character. The Monterey shale differs from all other
formations in the mapped area and is remarkable for the following
reasons : ( 1 ) widespread areal extent ; ( 2 ) low percentage of clastic sedi-
ment; (3) presence of volcanic material; (4) high percentage of chemi-
cal sediments ; (5) very high percentage of siliceons sediments ; (6) large
amount of organic material; (7) rhythmic bedding.
The Monterey shale, and perhaps the overlying Sisquoc, are the only
Tertiary formations deposited over the entire mapped area. The local
absence of Monterey shale under the northeastern San Rafael foothills
and in parts of the Santa Ynez Mountains is due to its removal by uplift
and erosion after deposition. The Monterey formation contains no mar-
ginal type sediments and there is no evidence that it was not deposited
over the entire mapped area. Local absence of the lower Monterey, how-
ever, may be due to non-deposition.
The Monterey shale is the only formation in the mapped area con-
taining almost no clastic material. Only the lowest (Relizian) portion
contains an appreciable amount of silt and clay. This material decreases
upward to almost none in the uppermost Monterey. Sand and con-
glomerate are absent except for the local occurrence of chert pebble
conglomerate and sand west of Gaviota Beach. The general absence of
clastic material in the Monterey formation is apparently due to wide-
spread submergence under an open sea and disappearance of the adjacent
land areas which furnished clastic materials to older formations.
The occurrence of the Tranquillon volcanics and Obispo tuff at the
base of the Monterey strongly suggests that volcanism had strong influ-
ence on the deposition of the siliceous sediments that make up most of the
Monterey. Thin layers of volcanic ash and some bentonite are common
throughout the Monterey shale. The Tranquillon rhyolitic eruptions may
have been a source of some of the enormous quantities of silica in the
Monterey shale, either by means of alterations of volcanic ash in the sea
water, or from submarine siliceous springs which may have issued
throughout Monterey time from the former areas of volcanic eruptions. ^^
There is no physical evidence to support these theories, except that the
upper Monterey generally becomes more cherty and siliceous in the
vicinity of Tranquillon Mountain. This is generally true of the lower
Monterey also, which consists predominantly of cherty shale in that
vicinity. Aside from the Franciscan, the Tranquillon is the only volcanic
series within the mapped area and the Monterey the only formation
containing appreciable amounts of volcanic ash.
The Monterey shale is believed to be essentially a chemical deposit,
made up predominantly of silica. Although much of this was deposited
organically in the form of diatom tests, the silica itself must have had a
chemical origin, and that not used by organisms must have settled out
from colloidal suspension and deposited in much the same manner as
calcium carbonate does to form limestone. The lower Monterey contains
an appreciable amount of limestone as beds averaging about a foot in
thickness. A thick basal limestone as much as 150 feet thick forms the
base of the Monterey in the canyon of El Jaro Creek. Although some of
the calcium carbonate making up the limestone was deposited orginally
by foraminifera and calcareous algae, most of it is of chemical origin.
^ Taliaferro, N. L., The relation of volcanism to diatomaceous and associated
siliceous sediments: Univ. California Dept. Geol. Sci. Bull., vol. 23, no. 1, pp. 1-56, 1933.
DIVISION OF MINKS
BULIJOTIN ir.O,
I'LATK 14
PLATY PORCELANEOUS SILICEOUS
SHALES
Member F, upper Monterey, near mouth of
Alegria Canyon.
4 — 13966
DIVISION OF MINES
BULLETIN 150, PLATE 15
"?=>*fe-
■ift't
*?■
A, THIN-BEDDED FORAMINIFERAL SHALE
Member D, lower Monterey shale, in Alegria Canyon.
B, CHERTY SILICEOUS SHALES
Member E, upper Monterey shale, near mouth of Jalama Canyon.
DIVISION OF MIXES
BULLETIN 150, PLATE 16
". iJ » •->• -4^
A, VIEW TVEST ALONG COAST FROM MOUTH OF CUARTA CANTON
Sisquoc shale exposed along beach : Monterey shale forms hills hack of coastal
terrace. Derrick of Wilshire Oil Companj- well No. ■Hollister" 1 on sea cliff.
^ -^i^^jj^
B. TYPICAL EXPOSURE OF PASO ROBLES TERRESTRIAL
CONGLOMERATE
7 miles east of Santa Ynez. Made up largely of shale pebbles.
DIVISION OF MINES
BULLETIN 150,
PLATE 17
'4
.'it- *"''3' ,'7 , *' i
>i'
TAR-SOAKED CONGLOMERATE AND
SANDSTONE
Near top of Monterey shale, east of Alegria
Canyon half a mile from beach.
1950] STRATIGRAPHY 41
Calcium phosphate was deposited in the form of eollophane which
makes up the buff-colored blebs and lenticular laminae in soft, dark
brown organic shales. This type of shale, kno^vn as phosphatic or "buff
and brown" shale in oil fields, is characteristic of the lower Mohnian and
Luisian portion of the lower Monterey.
The Monterey shale is remarkable for its enormous quantities of
silica. The siliceous rocks of the Monterey and part of the overlying
Sisquoe formation are of three types, as recognized by Bramlette,^® all
of which are finely laminated and grade into one another : (1) diatomite
(soft, white, "punky," lightweight, porous); (2) porcelaneous shale
(hard, brown, white-weathering shale with platy fracture) ; (3) cherty
shale (very hard, brittle, vitreous, black, bro^vn, gray, to white opaline
shale with close sub-platy to conchoidal fracture ; contains laminae or thin
layers of black to brown chalcedonic chert [flint] ; commonly minutely
contorted, brecciated and recemented by veinlets of secondary opal or
chalcedony).
Porcelaneous and cherty shale are characteristic of the upper Mon-
terey, and occur locally in the lower ^Monterey. The diatomite is
characterictic of the lower Sisquoe formation in some areas, but is also
locally interbedded in the siliceous shales of the upper Monterey.
Considering the areal extent of the Monterey shale in California,
it is difficult to postulate where such a great amount of silica could have
originated. Many theories have been proposed, and these are thoroughh^
discussed by Taliaferro ^^ and Bramlette.^^ The inorganic theory as
advanced bv Taliaferro "^ has alreadv been discussed. The organic theory-
postulates that the hard siliceous shales were formed by alteration of
organically deposited diatomite by deformation,^" or by compaction from
overljing sediments.^^ However, neither the source of the siliceous sedi-
ments nor the process by which they were formed can be accounted for
satisfactorily by these theories, and there is little direct evidence to
support them. How the enormous quantity of silica was made available,
or exactly how it was deposited to form siliceous shales, is not known.
The normal sequence of the three types of siliceous sediments is the
order given, cherty shale making up the lower part of the upper Mon-
terey', and grading upward through porcelaneous shale into diatomite.
]\Iuch of the contact between the siliceous shale and diatomite is sharp
and easily mappable. Detailed mapping shows that the three t^-pes are
not at the same position in the section at all places ; in some localities they
are interbedded. From these relationships it is concluded that these three
tyipes of siliceous sediments are of primary origin and that they are f acies,
as suggested by Regan and Hughes,^^ determined b}^ local conditions of
deposition, the relative amount of free .silica deposited, and the amount
deposited by organisms.
38 Bramlette, M. N., Monterey formation of California and origin of its siliceous
rocks : U. S. Geol. Survey Prof. Paper 212, pp. 1-55, 1946.
^" Taliaferro, N. L.., The relation of volcanism to diatomaceous and associated
siliceous sediments: Univ. California Dept. Geol. Sci. Bull., vol. 23, no. 1, pp. 1-56, 1933.
»8 Op. cit.
»9 Op. cit.
*° Arnold, R., and Anderson, R., op. cit.
" Bramlette, M. N., op. cit.
<^ Regan, L. J. Jr., and Hughes, A. "W., Fractured reservoirs of the Santa Maria
district, California : Am. Assoc. Petroleum Geologists Bull., vol. 33, no. 1, pp. 32-51, 1949.
5—13966
42 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
The Monterey shale is notable for its unusually large amount of
organic debris, composed largely of remains of microscopic plant and
animal life. The highly siliceous content of the marine waters following
eruption of the Tranquillon volcanics apparently brought about a con-
dition favoring unusually prolific development of one-celled plants such
as diatoms. These were produced in such enormous quantities, especially
during late Monterey deposition, that their siliceous tests accumulated to
form thick deposits of impure to nearly pure diatomite, making up a
large percentage of the siliceous shales of the Montere.y. Along with the
diatom debris but in lesser amounts were deposited siliceous remains of
animals, such as tests of radiolaria and arenaceous foraminifera, and
sponge spicules. Calcareous tests of foraminifera are extremely prolific
only in the lower ]\Ionterey, and tests of arenaceous foraminifera are
abundant in both members. The former are extremely abundant in some
layers, especially in the phosphatic shales and thin limestone beds.
Chitinous remains of fish scales are abundant throughout the Monterey.
Molluscs are rare except for mud-pectens {'' Pccten" pecJxhami) and
other small thin-shelled pelecypods.
Besides the remains of organic life the Monterey shale contains a
great amount of organic matter in the form of hydrocarbons or bitu-
minous material. Where unweathered the Monterey shale is generally
impregnated with this material, which gives the characteristic bitumi-
nous odor when freshly broken and imparts a dark brown color to the
sediments. Where exposed, this organic matter leaches or oxidizes so
that the rocks become light colored or even white. It is most abundant
in the upper Monterey, which produces practically all the oil at Lompoc
and Zaca oil fields. This organic matter was probably deposited in water
too deep and too far below wave and current action to be subject to
oxidation, and consequently became buried and preserved in the fine
sediments of the Monterey.
A characteristic feature of the Monterey shale is the rhythmic bed-
ding, which is described in detail by Bramlette.'^^ This feature is most
apparent in the siliceous shales, in which the rhythmic beds are 1 inch or 2
inches thick and consist of hard porcelaneous or cherty shale alternating
with layers of softer somewhat more clayey shale. Superimposed on this
rhythmic sequence of beds is a series of fine laminae which likewise shows
a definite alternation of layers that contain abundant siliceous or organic
matter with those that contain less. These rhythmic laminae are believed
to represent annual cycles of deposition.
Age. The lower Monterey and upper Monterey are mapped as
lithologic units and the contact separating them is not necessarily a time
horizon. The ages of the various sub-members west of Gaviota are already
indicated. In the Santa Ynez Mountains the upper Monterey falls into
the lower Delmontian stage and upper Mohnian stage {Bolivina kughesi
zone), upper Miocene, and locally includes some lower Mohnian. The
lower Monterey falls into lower Mohnian {Baggina calif or nica zone) ;
Luisian stage (Siphogenei'ina collomi-ValvuIineria californica zone) ;
Kelizian stage (SipJiogenerina hranneri zone), middle Miocene; and
uppermost Saucesian stage {Uvigerina ohesa zone), uppermost lower
Miocene.
*3 0p. cit, pp. 30-34.
1950] STRATIGRAPHY 43
Sisquoc Formation
The Sisquoc formation in southwestern Santa Barbara County con-
sists of from 3000 to 5000 feet of diatomite and diatomaceous clay shale
lying" above the JMonterey shale and below the Foxen and Careaga for-
mations. The Sisquoc formation is exposed on both flanks of the Santa
Ynez Range, on Burton Mesa, and throughout the Purisima Hills. The
type locality is on the south side of Sisquoc River canyon near the mouth
of Foxen Canyon, north of the area mapped, where the Sisquoc consists
predominantly of fine sands.
The Sisquoc formation is best developed in the Purisima Hills, where
it attains a thickness of nearly 5000 feet. The general sequence here is
as follows :
Foxen claystone
Conformity
Gray-white poorly bedded diatomaceous claystone, with a pre-
dominant 200-foot layer of laminated white diatomite
("marker diatomite") at middle 1000± feet
Variations from light-gray massive to poorly bedded diato-
maceous claystone with couchoidal, spheroidal, or splintery
fracture, to cream-white well-bedded to massive impure
diatomite ; north of Lompoc field lowest exposed portion
contains layers up to 6 inches of massive brown opaline
chert ; in eastern Purisima Hills lowest portion becomes
massive to laminated white diatomite 4000± feet
Massive, semi-friable fine-grained brown sand, impregnated
Avith tar 0-50 feet
Conformity
Monterey — laminated diatomite and platy siliceous shale
In the Burton Mesa area the Sisquoc formation is about 2300 feet
thick and is similar in lithology to the Sisquoc of the Purisima Hills. The
upper 300 feet is composed of nearly pure laminated white diatomite
which is probably the equivalent of the marker diatomite of the Purisima
Hills. The remaining 2000 feet consists of diatomaceous claystone with
splintery fracture, of which the low^est 700 feet becomes thin-bedded
diatomaceous porcelaneous shale which grades downward into Monterey
platy shale.
In the Santa Rita Hills and west along the hills south of Lompoc
Valley the lowest 750 to 1000 feet of Sisquoc consists of soft, white, lam-
inated, punky, almost pure diatomite. This is quarried extensively south
of Lompoc. It generally g-rades downward into cherty shale of the under-
lying Monterey, but at several localities near the Santa Ynez River
between Salsipuedes and Drum Creeks the base of the diatomite is
marked by a few feet of sand locally, or by a thin layer of phosphatic
pebbles, which can best be seen in a road cut near the mouth of Drum
Canyon and on the Santa Rosa road east of Salsipuedes Creek. In the
eastern Santa Rita Hills the Sisquoc diatomite overlaps the entire upper
Monterey, thus indicating a local unconformity. The punky diatomite
member "of the Sisquoc grades upw^ard into 750 to 1050 feet of massive
cream-white diatomaceous claystone. This is unconformably overlain by
the Careaga sand.
On the south flank of the Santa Ynez Range the Sisquoc shale, usu-
ally mapped as ' ' Santa Margarita ' ' shale, is exposed along the coast from
Gaviota Beach to the mouth of Jalama Canyon. This is the youngest
formation exposed on the coast. The maximum thickness, about 3200 feet,
44 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 15U
is exposed in the syncline north of Point Conception, where the section
is as follows :
Top of section eroded
Cream-white massive to poorly bedded somewhat punky silty
diatomite with conchoidal fracture SOO feet
Light brownish gray massive to poorly bedded silty to diatoma-
ceous claystone, crumbly, with spheroidal fracture 1400 feet
Light brownish gray well-bedded clay shale with splintery frac-
ture, to laminated thin-bedded siliceous shale with platy
fracture 1000 feet
Brown massive compact sandy siltstone, highly bituminous ;
disappears west of Cojo Canyon ; between Cuarta and Gaviota
Canyons contains lenses up to 75 feet of well-bedded breccia-
conglomerate composed of Monterey cherty shale debris in
tar-soaked sandstone matrix 0-100 feet
Disconformity
Monterey porcelaneous shale
Wells drilled throughout the San Rafael foothills encounter the
Sisquoc formation below the Careaga sand. Cores indicate the Sisquoc
here to consist of massive light-gray diatomaceous siltstone or shale grad-
ing upward into Careaga sand and lying unconformably on previously
tilted and folded Monterey shale. The Sisquoc thins rapidly from Los
Alamos syncline by successive buttressing out of the lower portion to an
average thickness of about 300 feet in the northeastern part of the area.
Here only the upper portion is present; it lies directly on Cretaceous
or Franciscan rocks. The Sisquoc is exposed only at Birbent Canyon
where it is upturned along the Little Pine fault. Here the Sisquoc con-
sists of about 150 feet of white diatomaceous siltstone grading upward
into Careaga sand and lying on serpentine.
The Sisquoc formation, like the underlying Monterey, is remarkable
for the great amount of diatom tests and remains of other siliceous organ-
isms which make up such a large part of it. Within the area mapped the
Sisquoc consists of an admixture of diatom debris and clay, in varying
proportions, deposited under an open sea. Tuffaceous material occurs in
small amounts. Unlike the Monterey formation, silicified layers are rare
in the Sisquoc except locally. Calcareous material and calcareous fora-
miniferal remains are scarce.
The lower 1000 feet of the Sisquoc formation is assigned to the Del-
montian stage of upper Miocene, and the remainder to lower (and per-
haps middle) Pliocene, on the basis of meager foraminiferal faunas
found in wells, and also upon molluscan faunas found in the sandy f acies
at Foxen Canyon north of the area mapped.^^
Foxen Claystone
The Foxen formation consists of about 800 feet of claystone lying
conformably between the Sisquoc diatomite below and the Careaga sand
above. Within the area mapped the Foxen crops out only in the western
Purisima Hills in northern Lompoc quadrangle ; the best exposure is at
" Woodring, Bramlette, and Lehman, op. cit., pp. 1350-1351.
1950] STRATIGRAPHY 45
the tA-pe locality 1^ miles south of Harris. From the Purisima Hills the
Foxen dips under Los Alamos Valley and extends northward to Santa
Maria Valley. The formation wedges out down the south flank of the
Purisima Hills, and also eastward along strike on the north flank.
At the type locality the Foxen formation is about 800 feet thick and
consists of light-gray massive claystone and siltstone containing fairly
abundant diatom and foraminiferal remains. Northwest along the strike,
just off the map, thin beds of buff sandstone containing phosphate pel-
lets appear. The Foxen formation reaches its maximum development
under Santa Maria Valley, where it attains a thickness of 2300 feet.
The relationship of the Foxen claystone to the Sisquoc diatomite is
fairly sharp but conformable, although an unconformity on the south
flank of the Purisima Hills is suggested by overlap of the uppermost
Sisquoc by the Foxen. Throughout all exposures the Foxen grades
upward into fine sands of the lower Careaga. Under the San Rafael foot-
hills the Foxen formation may be represented by the thin transitional
beds between the Sisquoc diatomite and Careaga sand, but is not recog-
nized.
The restricted areal distribution of the Foxen claystone probably
indicates that it was laid dovna. under an embayment opening on the
northwest into the ocean via Santa Maria Valley. Elsewhere the region
mapped was apparently uplifted as indicated by the regional uncon-
formity between the Sisquoc and Careaga formations.
On the basis of foraminiferal f aunules the Foxen formation has been
assigned to middle and upper Pliocene.^^
Careaga Sand
The Careaga formation is a marine sand of upper Pliocene age lying
conformably below the terrestrial Paso Robles formation and above
Foxen, Sisquoc, or Monterey formations. The Careaga sand is present,
either exposed or buried, throughout virtually all of the Santa IVIaria
Basin with the exception of Burton :\Iesa. It crops out on both flanks of
the Purisima Hills, north flank of the Santa Rita Hills, and southwest of
Lompoc. It also crops out east of Santa Ynez where it extends beyond
Los Olivos quadrangle and was mapped by Nelson ^^ as the Fernando
formation. Under Lompoc Valley fossiliferous Careaga sand is encoun-
tered below aUuvium in water wells. It is deeply buried under upper
Santa Ynez Valley and the San Rafael foothiUs, but crops out northwest
of Birbent Canyon.
Like the Foxen claystone, the Careaga sand attains its maximum
development under Santa Maria Valley, where it is some 1400 feet thick.
Under Los Alamos Valley it is probably about 1000 feet thick. It is about
700 feet thick in the Purisima and Santa Rita Hills, and about 300 feet
thick in the exposures east of Santa Ynez.
The Careaga sand is well exposed along the north flank of the
Purisima Hills, especially at the type locality 2 miles south of Careaga
station. Here the Careaga is about 725 feet thick and consists of two
members, as follows :
«Woodring, Bramlette, and Lohman, op. cit., 1354-1355.
"Op.cit., pp. 372-374.
46 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Paso Robles formation
Conformity
Upper Careaga (Graciona mentlcrj
Loose medium-grained gray-white sand 150± feet
Same as above, but with abundant well-rounded pebbles up
to 2 inches in size of quartzite, porphyritic igneous rocks,
and Monterey chert and shale ; local occurrences of fossil
pelecypod reefs 50± feet
Hard calcareous sandstone reef with abundant Dendraster
ashleyi; (Dendraster reei) 0-10 feet
Lower Careaga (Cehada memher)
Friable massive yellow-buff fine-grained sandstone 400± feet
Semi-friable well-bedded buff very fine-grained sandstone
and minor interbeds of sandy siltstone 125± feet
Gradational contact
Foxen claystone
These two members are mappable throughout most of the Purisima
and Santa Rita Hills. However, only the upper member is present in the
Purisima Hills east of Zaca Creek and east of Santa Ynez. In the former
area no fossils are present and it is possible that some of the sand mapped
there as Careaga may belong to a younger formation. In the latter area
the Dendraster reef marks the base of the Careaga sand.
The lower Careaga member is persistently fine and even grained,
and was probably deposited under calm shallow waters of a protected
bay similar to that in which was deposited the Foxen claystone, but more
extensive. The lower Careaga was thus laid down under transgressing
waters.
The upper Careaga member is a littoral or beach-sand deposit of
varying lithology. The pebble bed at the base of this member is very
persistent and indicates a widespread break in sedimentation. The basal
Dendraster (sand dollar) reef indicates deposition under very shallow
water. At Cebada and Purisima Canyons the upper Careaga contains
very thick, irregular lenses of crossbedded coarse sand, often pebbly,
calcareous, fossiliferous and hard. These v/ere probably deposited as
sand bars. The uppermost portion of the upper Careaga generally con-
sists of as much as 300 feet of loose sand devoid of pebbles or fossils,
which appears to be wind-blown dune sand. The upper Careaga sand was
deposited under a widespread but very shallow embayment under which
nearly the entire Santa ]\Iaria Basin was submerged. It represents the
final stage of marine deposition in this area.
The relationship of the Careaga sand to the underlying Foxen clay-
stone is conformable in the northwestern Purisima Hills. However where
the Careaga sand lies on Sisquoc or Monterey formations, such as in the
eastern Purisima Hills and Santa Rita Hills and eastward, the relation-
ship becomes a widespread unconformity, for the most part with angular
discordance. Under the San Rafael foothills and at Birbent Canyon the
Careaga sand seems to grade downward into the Sisquoc diatomite,
despite the absence of the Foxen claystone. The relationship of the
Careaga sand to the overlying Paso Robles terrestrial beds is everywhere
conformable, and locally difficult to determine ; but the base of the latter
is usually marked by the first appearance of white marl followed by clay.
The Careaga sand contains a large molluscan fauna. The following
are the more important species occurring in both members. Those marked
with an asterisk (*) are more abundant in the lower Careaga; those
unmarked, in the upper Careaga :
1950] STRATIGRAPHY 47
Pelecypoda
* Lucina cf. annulata
Macoma cf. nasuta (Conrad)
* Pecton (Lyropcpten) cerrosensis Gnbl)
* Pecten (Patiuopecten) healeyi (Arnold)
Pseudocardium cf. densatum (Conrad)
"Venerupis" cf. hannibali
* Yoldia cf. cooperii Gabb
Gastropoda
Drillia graciosana Arnold
Xassa monmiaiia Martin
Olivella biplicata
* Trochita radians Lamarck
* Turritella gonostoma hemphilli
Echinoidea
Dendraster ashleyi
On the basis of this fauna. AYoocTring ^^ assigns the Careaga sand
to upper Pliocene, correlative with the San Joaquin formation of San
Joaquin Valley.
Paso Robles Formation
The Paso Robles formation is a series of terrestrial gravels, sands,
and clays of probable uppermost Pliocene and lower Pleistocene age lying
conformably on the Careaga sand. Like the Careaga sand, the Paso Robles
formation is present throughout the Santa Maria Basin, with the excep-
tion of Burton Mesa. It is most extensively exposed in the San Rafael
foothills where it attains a maximum thickness of some 4500 feet along the
northeastern portion of these hills adjacent to the San Rafael Mountains.
To the southwest it gradually thins to about 2000 feet in the A^cinity of
Los Alamos Valley, and to about 700 feet under Santa Rita Valley. It
is absent under Lompoc Plain.
Poorly consolidated gravels, sands, and pebbly clays or. silts con-
stitute the Paso Robles formation. The gravels are usually cross-bedded,
light gray, and in most areas are made up almost entirely of white shale
pebbles derived from the ]\Ionterey shale. Sands are generally buff and
well bedded, often pebbly. Clays and silts are massive to bedded, usually
greenish but locally light reddish, and commonly pebbly.
There is no defined sequence in the Paso Robles formation, but in
general clays and silts predominate in the lower portion and gravels in
the upper, which becomes coarser toward the top.
In the San Rafael foothills the lower 2000 feet of Paso Robles
generally consists of greenish-gray clays and minor white shale pebble
gravels. VTest of Zaca Canyon a member of loose massive sand constitutes
the lower 700 ±: feet of Paso Robles. The upper portion of the Paso Robles
is made up largely of gravels which become increasingly coarse toward
the top of the formation. These gravels are made up of ^Monterey white
shale pebbles, but adjacent to the Franciscan exposures of the San Rafael
Mountains, Franciscan debris becomes increasingly abundant toward the
top and makes up the entire content of the uppermost portion.
On the north flank of the Purisima Hills the Paso Robles formation
consists of about 2000 feet of white shale pebble gravels with some clays
in the lower portion. A prominent white freshwater limestone bed up to
3 feet thick occurs near the base in the basal clay member. A similar lime-
stone bed, as much as 12 feet thick, known as Los Alamos limestone,
occurs 1200 feet higher. Both these limestone beds contain small fresh-
water fossils.
*■? Woodring, Bramlette, and Lohman, op. cit., p. 1358.
48
SOUTHWESTERN SANTA BARBARA COUNTY
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50 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
In the vicinity of Santa Rita Valley the Paso Robles consists of clays
and gravels with several lenses of loose, windblown sand.
Orcutt Sand
The Orcutt formation ranges from less than a foot to 150 feet in
thickness. It consists of nonmarine sand and gravel resting discordantly
on the Paso Robles and older formations, and has been assigned to
middle or upper Pleistocene. The type area is on the north flank of the
Casmalia Hills west of Orcutt, north of the area mapped.
The Orcutt formation is extensively exposed in the vicinity of
Lompoc Valley and Burton Mesa, and on top of the western Purisima
Hills. In these areas it reaches a maximum thickness of 150 feet and
consists of loose, medium-grained massive light-buff sand, probably
deposited by wind blowing from the ocean beach to the west. The top of
this sand is locally indurated by iron oxides into hard reddish-buff sand-
stone. The basal portion contains numerous well-rounded pebbles of
quartzite, acidic igneous rocks, and JMonterey chert and shale.
The Orcutt formation lies unconformably on older formations which
have been previously folded, but is itself only gently tilted toward
Lompoc and Santa Rita Valleys. It is tilted as much as 25° in the latter.
Terrace Deposits
In the Santa Ynez Valley and along valleys of the main streams are
several stream-laid terrace gravels, some as much as 75 feet thick. In the
Santa Ynez Valley the oldest and most extensive is tilted as much as 15°
and may be the equivalent of the Orcutt formation farther west. This can
best be seen on the road east of Solvang. Several younger terraces are
prominent along the course of the Santa Ynez River.
Along the coast are terrestrial gravels apparently deposited on the
wave-cut terraces. The low coastal plain which extends back to about
two miles from shore is covered with stream-laid cobble-gravel, silt and
sand as much as 75 feet thick. On the highway 1 mile west of Gaviota
and also at Alegria Canyon, the basal portion contains fossiliferous
beach sand. Small remnants of higher, elevated terrace deposits are found
locally along the coast.
Alluvium
All stream-laid vallej' fills of Recent age are mapped as alluvium,
which consists of unconsolidated loam}^ clays, silts, sands, and gravels,
totaling as much as 170 feet in thickness.
The thickest and most extensive alluvial fill underlies Lompoc Plain.
Water-well logs indicate that the upper 120 feet of alluvium on this flat-
land consists of sand and clay and minor amounts of gravel, and the lower
50 feet of water-bearing gravel. J. E. Upson ^^ has prepared a subsurface
map and cross-sections based on logs of water Avells drilled in Lompoc
Plain, which show that the upper 120-foot member underlies the entire
plain, but that the lower 50-foot gravel member is present mainly in the
northern portion, and in the extreme eastern and western portions is
restricted to the vicinity of the Santa Ynez River channel. It is interest-
's Upson, J. E., Thomasson, H. G. Jr., and others, Geology and water resources of
Santa Ynez River valley, Santa Barbara County, California : U. S. Geol. Survey dupli-
cated rept, pis. 507, 508, June 1947. (Final report in press.)
1950] STRUCTURE 51
in2 to note that throuslioiit the areal extent of this gravel the base is
approximately 170 feet below the ground surface, and is consequently
below sea level under much of Lompoe Plain, and even extends out to
sea for an unlmown distance beyond the mouth of the Santa Ynez River.
This condition indicates subsidence during Recent time, or as Upson ■^^
believes, a rise of sea level following the late Pleistocene Wisconsin glacial
period.
Between Lompoe and San Lucas bridge the alluvium along the Santa
Ynez River floodplain is similar to that of Lompoe Plain but thinner, the
upper member being about 40 feet thick, and the basal gravel member
about 25 feet thick.
In upper Santa Ynez Valley, Los Alamos Valley, and level-bottomed
canyons of the San Rafael foothills the alluvium is indistinguishable
from terrace gravels and the Paso Robles formation, but contains con-
siderable water-bearing gravel.
The alluvium which fills flood-plains of the major streams of the
Santa Ynez ^fountains and Purisima Hills is less than 100 feet thick, and
consists mainly of loamy silt with minor amounts of sand and gravel.
Along the coast this alluvium extends below sea level and out to sea
beyond the mouths of the canyons.
STRUCTURE
Southwestern Santa Barbara County comprises parts of four major
structural provinces. These are, starting from the south: (1) Santa Ynez
Mountain uplift: (2"^ Lompoe lowland; (3^ Los Alamos syncline; and
(4) San Rafael Mountain uplift.
The Santa Ynez Range is made up of a very thick Cretaceous-Terti-
ary sedimentary section uplifted along the Santa Ynez fault and by
geantielinal folding.
The Lompoe lowland is an area of low relief, comprising Burton
Mesa and Lompoe Valley, which wedges out eastward through Santa
Rita Valley and lower Santa Ynez Valley. This lowland wedge is in part
structurally synclinal but is regionally a ' ' high ' ', in which the Franciscan
basement is relatively close to the surface and covered by a thin, little-
disturbed sedimentary section. This thin-blanketed wedge separates the
thick-blanketed Santa Ynez Mountains on the south from the tMck-
blanketed Los Alamos s;^Ticlinal area on the north.
Los Alamos syncline is a deep structural downwarp traversing Los
Alamos and upper Santa Ynez Valleys. It is developed where the Terti-
ary-Quaternary section of Santa Maria Basin attains its maximum
thickness. This trough is flanked by the Purisima Hills on the south and
the San Rafael foothills on the northeast, both of these being anticlinal
uplifts developed where the sedimentary section thins rapidly from the
deep s^Ticlinal trough.
The San Rafael Mountains have been uplifted largely by faulting
along the southwestern base.
Nearly all axes of folds throughout the region mapped trend slightly
north of west, indicating crustal shortening at right angles to that trend.
This shortening apparently resulted from a regional stress system of com-
pressive forces acting from a north-northeast south-southwest direction.
*3 Upson, J. E., Late Pleistocene and Recent changes of sea level along the coast
of Santa Barbara Countj-, California : Am. Jour. ScL, vol. 247, no. 2, pp. 94-115, 1949,
52
SOUTHWESTERN SANTA BARBARA COUNTY
[Bull. 150
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1950] STRUCTURE 53
The forces may have been directly opposing, but oblique-slip movement
along many of the eastward trending faults in the Santa Ynez Mountains
suggests a local counter-clockwise rotational force.
The various sedimentary^ provinces within the region mapped have
reacted in various ways to the regional stress. Synclinal deeps such as Los
Alamos syncline have resisted compression. This is true also of regional
"highs" such as the Lompoc lowland, indicating that the Franciscan
basement resisted compression. Areas of least resistance and greatest
deformation are those in which the sedimentar}'- section thickens or thins
between these two extremes.
Santa Ynez Mountains
The western Santa Ynez Mountains consist of a northern and a south-
ern structural block separated by the eastward-trending Santa Ynez-
Pacifico fault zone.
Southern Structural Block
The southern structural block comprises the higher Santa Ynez
mountain range extending eastward from Gaviota Canyon, and also the
low ridge extending westward through the hills south of Jalama Canyon.
The higher Santa Ynez mountain range is a block consisting of a
southward-dipping homocliue in a very thick Cretaceous-Tertiary sedi-
mentary series uplifted along the Santa Ynez fault on the northern
base. The crest of this range is essentially a strike-ridge trending par-
allel to the Santa Ynez fault at a distance of about 1^ miles south of it.
This mountain block is abruptly terminated on the west by the south
branch of the Santa Ynez fault extending from Gaviota Pass southwest
to the mouth of Alegria Canyon. Gaviota Gorge is an antecedent canyon
cutting through the extreme western portion of this uplifted block.
The low mountain ridge extending from Las Cruces westward to a
point south of Jalama Canyon is a structural block similar to that of
the higher Santa Ynez Range. It consists of a southward-dipping homo-
cline in a slightly thinner Cretaceous-Tertiary sedimentary section, and
is uplifted on the north along three faults, namely, the Santa Ynez
(north branch), Gaviotito, and Pacifico faults. The crest is likewise a
strike-ridge, but is broken at Santa Anita Canyon by the Pacifico fault.
This homoclinal block in part forms the south flank of the Pacifico anti-
cline which comes into it from the northwest at Santa Anita Canyon,
and also the south flank of the Jalama anticline, coming in from a simi-
lar direction at Jalama Canyon.
Northern Structural Block
The northern structural block of the western Santa Ynez Mountains
takes in that portion lying north of the Santa Ynez-Pacifico fault zone,
including the Santa Rosa Hills, Santa Rita Hills, and Tranquillon Moun-
tain ridge. The stratigraphic section of this northern block is about the
same as that of the southern block, but is considerably thinner, and
broken by six, possibly seven unconformities, indicating that the area
was subjected to that many periods of deformation, uplift, and erosion.
Consequently the structure is extremely complex. Details are shown on
the areal geologic map and cross-sections. In general, the structure is
one in which numerous minor folds, trending roughly N. 75° W., are
developed in the Miocene formations, on the whole amounting to an
54 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
anticlinorum. The older formations are compressed into several large
folds with a similar trend, but these formations dip regionally to the
south so that successively older formations underlie the Miocene from
south to north.
The structure of the San Lucas-Wons Canyon area is that of a homo-
cline in Lower Cretaceous and Eocene sediments dipping steeply north.
These sediments are unconformably overlain by the Monterey shale,
which in general dips away from them on both sides. The southwestern
contact is possibly a fault contact, but evidence is not conclusive. It is
therefore mapped as an unconformity like the northern contact.
Santa Ynez Fault System
The Santa Ynez fault and lesser faults associated with it constitute
an active fault system of great magnitude, movement along which is
largely responsible for the uplift of the Santa Ynez Mountains. From
Gaviota Pass the Santa Ynez fault has been traced eastward continu-
ously along the northern base of the high Santa Ynez mountain range
for more than 65 miles into Sespe Canyon, Ventura County. The south
block is up along the entire course and the throw amounts to several
miles. Westerly from Gibraltar Dam the fault dips steeply south ; farther
east it becomes vertical; at Matilija Canyon it dips north.
The Santa Ynez fault is marked by a zone of gouge and crushed
rock, often several hundred feet wide. The fault is well expressed topo-
graphically, as it in most places forms the base of the steep north slope
of the Santa Ynez mountain front. It is generally marked by a topo-
graphic depression between this mountain front and the lower hills to
the north, and is locally followed by streams emerging from the Santa
Ynez Mountains.
A component of horizontal or lateral movement along all members
of the Santa Ynez fault system in which the south block has moved rela-
tively eastward, is strongly suggested by topographic, structural, and
stratigraphic relations. West of Gaviota Pass the Santa Ynez fault
divides into several faults of relatively small magnitude, all having the
same trend and movement as the main Santa Ynez fault. The Pacifico
fault is part of the Santa Ynez fault system.
From regional mapping it is concluded that the Santa Ynez fault
system is a deep-seated zone of recent activity, trending eastward for a
total distance of more than 80 miles. Oblique-slip movement of great
magnitude has taken place along this zone ; the southern block has been
uplifted to form the Santa Ynez Range and has moved eastward rela-
tive to the northern block.
Santa Ynez Fault. Within Los Olivos quadrangle east of Quiota
Canyon the Santa Ynez fault is composed of two closely spaced faults.
The southern of these is the main Santa Ynez fault, which brings Eocene
and Upper Cretaceous of the Santa Ynez mountain block on the south
against Rincon-Vaqueros-Sespe on the north. At AVons Canyon this fault
dips as low as 15° S., but to the east and west the dip steepens to near
vertical. The northern fault is vertical and follows a straight course,
bringing Rincon-Vaqueros-Sespe on the south in contact with Monterey
shale (which lies directly on the Espada formation and serpentine at
San Lucas and Wons Canyons) on the north. Between Quiota Canyon
and Gaviota Pass the Santa Ynez fault is a single fault which brings the
Jalama formation on the south against Rincon shale on the north, with
a throw amounting to about 2 miles.
1950] STRUCTURE 55
Throughout Los Olivos quadrangle the Santa Ynez fault shows some,
though not conclusive, evidence of a horizontal or lateral component of
movement, the south block having moved relatively eastward. Such move-
ment, in which the block opposite the observer moved relatively to the
left, is termed left-lateral displacement by Hill.^° Topographic evidence
of lateral movement on this fault is suggested by so-called "rift" topog-
raphy along its course ; that is, a general topographic depression locally
followed by streams and marked by notches through hills crossed by the
fault. Such topography is characteristic of recently active strike-slip and
oblique-slip faults in California. Evidence for left-lateral movement
along the Santa Ynez fault is indicated by offsetting of some canyons
emerging from the north slope of the Santa Ynez Range, such as Quiota
Canyon, which follow the fault always in a westerly, never an easterly,
direction, before resuming their northward course. Structural evidence
of left-lateral movement is suggested by the intersection of folds in the
northern block always from a northwesterly, never a northeasterly direc-
tion, indicating left-lateral horizontal drag. Near-horizontal grooves have
been found in the fault gouge, where it is exposed on Highway 101 near
Gaviota Pass, and also in a minor parallel fault-plane on the old highway
half a mile east of Gaviota Pass. Stratigraphic evidence of left-lateral
movement along the Santa Ynez fault is suggested by the great difference
of the stratigraphic section on either side of the fault at San Lucas and
TTons Canyons. The mountain block on the south is made up of at least
15,000 feet of Upper Cretaceous, Eocene, Oligocene, and lower Miocene
sediments, which do not appear on the northern block where Monterey
shale directly overlies Lower Cretaceous or Upper Jurassic, but which
are present west of Quiota Canyon. This stratigraphic anomaly may be
explained by a great amount of left-lateral .strike-slip displacement along
the Santa Ynez fault.
Santa Tnez Fault, South Branch. At Gaviota Pass the Santa Ynez
fault di^^des in two, from which point the south branch extends south-
westward to the ocean at the mouth of Alegria Canyon. Displacement
decreases rapidly from Gaviota Pass and the fault supposedly dies out
under the sea. This fault appears to dip about 60 ~ X., and movement has
been upward on the southeast side, although some apparent reversal of
throw is indicated at Alegria Canyon. However, this condition may be
due to possible left-lateral movement. A hot sulfur spring issues from
the fault south of Las Cruces.
Santa Ynez Fault, Xorth Branch. From Ga^dota Pass the steep-
dipping north branch of the Santa Ynez fault extends westward for
about 6 miles. Movement was upward on the south side of the fault, the
maximum displacement being about 5000 feet. Displacement decreases to
the west and the fault becomes a south-dipping thrust which dies out into
the overturned axis of the Pacifico anticline.
Pacifico Fault. About half a mile sotith of where the north branch
of the Santa Ynez fault dies out the movement is taken up by the Pacifico
fault. This is the largest fault west of Gaviota Canyon, trending from
Agua Caliente Canyon west for about 10 miles to Jalama Canyon. Santa
Anita Creek flows eastward for some 3 miles along this fault before turn-
ing south. The east-trending portion of Santa Anita Canyon is known as
the Pacifico, from Avhich this fault was named. Movement has been
»Hill, M. L., Classification of faults: Am. Assoc. Petroleum Geologists Bull., vol. 31,
no. 9, p. 1670, 1947.
56 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
upward on the south side of the fault, which dips very steeply south, and
attains a maximum throw of about 5000 feet at the upper Pacifico. Here
it splits into two closely spaced faults, which die out toward the west
into the Jalama Canyon anticline. A left-lateral component of horizontal
niovement along this fault is suggested by associated folds on the north
side, which intersect it from the northwest.
At the head of Bulito Canyon immediately south of the Pacifico fault
are three small cross-faults subsidiary to the Pacifico fault, each with
right-lateral displacement. The Jalama sandstone bed between these
faults strikes N. 60° E., which is anomalous to the normal easterly strike.
This condition suggests that these are small fault blocks rotated counter-
clockwise by probable left-lateral horizontal drag along the Pacifico
fault.
Bulito Fault. South of the Pacifico fault is a small vertical strike
fault referred to as the Bulito fault, traceable for about 3 miles. It is
difficult to recognize as it is so nearly parallel to the beds, but is clearly
indicated by partial repetition of the Cozy Dell and Matilija formations.
Left -lateral displacement is suggested by offset contacts.
Gaviotito Fault. From the Pacifico fault in the Pacifico. the Gavio-
tito fault branches off and extends north of east for about 4 miles. It dips
steeply, and the south block has been elevated and moved eastward rela-
tive to the north block, as indicated by oft'set contacts and the offsetting
of the axis of the Pacifico anticline.
Cojo Fault. The Cojo fault is a small north-dipping thrust fault
about 4 miles north of Government Point. It is traceable for about 2 miles
and appears to dip about 45° N. Offset contacts suggest left-lateral dis-
placement whereby this fault may be related to the Santa Ynez fault
system.
Other Faults in the Santa Ynez Mountains
Canada Honda Faidt. Traceable from Point Pedernales for about
6 miles eastward up Cafiada Honda, is the Caviada Honda fault. This
fault dips steeply south, and has a maximum throw of about 3000 feet,
which brings Jurassic, Cretaceous, and Eocene rocks on the south against
Monterey shale on the north. The latter formation is tightly crumpled
into numerous sharp folds which intersect the fault from a northwesterly
direction. This relationship indicates left-lateral horizontal drag along
the fault, the south block having moved relatively eastward as well as
upward.
Santa Rita Faults. Some distance farther east, but in line with the
Canada Honda fault, are three small en echelon faults trending about
N. 75° E. for some 3 miles in the Santa Eita Hills. These are the Santa
Eita faults, similar to the Caiiada Honda fault but of less magnitude.
The largest brings Monterey shale on the south against Sisqnoc diatomite
on the north. Here the Monterey shale is tightly compressed into folds
intersecting the fault at a sharp angle from the east. This condition, as
well as offset contacts, indicate left-lateral horizontal movement along
these faults as along the Canada Honda fault.
Much of the intervening area between the Santa Eita and Canada
Honda faults is a line-up of tightly compressed small closed anticlines en
echelon in the Miocene, and trending about N. 75° W. The Caiiada
Honda and Santa Eita faults and the intervening and associated sharp
^
1950] STRUCTURE 57
folds -were developed along a zone of oblique-slip movement ; the sontliern
block moved upward and eastward relative to the northern block, in a
manner exactly similar to the Santa Ynez fault system, but on a smaller
scale.
Faults in TranquiUon Monniain Area. Near Honda School in
Canada Honda is a small fault that trends northeast for about 2 miles.
Offset contacts indicate movement along this fault to be left-lateral, the
southeastern block having moved relatively nortlieastward.
Between Caiiada El ]\Iorida and Caiiada El Jolloru are three minor
vertical faults trending about N. 75° E. ; upthrow has been on the south
side, in each ease.
Two very old faults have been found near TranquiUon Peak. A
mile east of this mountain is a northwest-trending fault which brings
Espada shale on the southwest against Gaviota standstone on the north-
east. The Vaqueros and TranquiUon formations extend right over this
fault, without being cut by it. This fault was therefore active after
deposition of the Gaviota but before the Vaqueros was deposited. It is
believed to extend about 2 miles in both directions from the portion
exposed but is concealed by the ]\Iiocene formations. The other fault, half
a mile southwest of the peak, trends eastward. It brings Espada shale on
the south against Eincon shale on the north, but the TranquiUon rhyolite
flow extends directly over it. unaffected. It is therefore younger than the
Rincon and older than the TranquiUon in age.
Faults in Santa Rosa-No joqui-Alisal Rills. Just north of the Santa
Rosa ridge is a steep, probable reverse fault that trends eastward for about
5 miles. Movement has been upward on the south side of the fault : max-
imum throw has been about 2500 feet. Left-lateral horizontal movement
may have taken place, as suggested by the axis of the Santa Rosa anti-
cline which intersects it from the southwest. South of Alisal ranch are
three minor reverse faults that dip south.
Throughout much of the Santa Rosa Hills and Xojoqui-Alisal area
are numerous steep normal faults, all upthrown on the north side. They
are minor faults, more or less equally spaced ; they show no evidence of
horizontal movement, and no relationship to the folding in the area.
These faults are difficult to account for, but a possible explanation is that
they constitute a series of northward-tilted blocks caused by differential
movement.
Befugio Fault. The Refugio fault extends from Tajiguas Canyon
eastward for about 6 miles to Capitan Canyon. It is well exposed at
Refugio Canyon where it causes repetition of the Vaqueros sandstone.
Here it dips 52° N., being a normal fault with about 500 feet of maximum
vertical displacement. A similar normal fault, with only 100 feet of throw,
occurs farther west in the Gaviota sandstone at San Onofre Canyon.
Erhuru Fault. A north-dipping normal fault known as the Erburu
fault forms in part the northern limit of production at Capitan oil field.
It is exposed on the east side of Corral Canyon in the excavation at the
Shell Company Xo. ''Covarrubias" 1-37 well, where it dips about 50° N.
Thrusting has been from the north, as the flat-lying Rincon shale is
turned up adjacent to the fault, so that the shale dips south. This anomaly
may be the result of horizontal movement along the fault. Associated
folding suggests that the south block moved relatively eastward. West
58 SOUTHWESTERNT SAKTA BARBARA COUNTY [Bull. 150
of Corral Canyon the fault dies out into an anticline. To the east it is
concealed by terrace deposits ; but it may be the continuation of the fault
exposed in Las Yeguas Canyon north of U. S. Highway 101, just east
of the area mapped. At Corral Canyon the Erburu fault brings flat-lying
Rincon shale on the south against north-dipping Monterey shale on the
north.
Las Yeguas Fault. Las Yeguas fault is well exposed on the sea cliff
1 mile east of Capitan. It is a reverse fault dipping about 60° N., bringing
Rincon shale on the north against Monterey shale on the south. Offset
contacts indicate probable horizontal movement, the south block having
been displaced relatively eastward.
Lompoc Valley and Burton Mesa
The structure of Lompoc Valley and Burton Mesa is very simple,
compared to that of the Santa Ynez Mountains. Wells drilled thoughout
this lowland area pass through a comparatively thin blanket of Orcutt,
Careaga, Sisquoc, and Monterey formations probably aggregating not
more than 4000 feet in maximum thickness, and then directly into Fran-
ciscan rocks. The structure of the Tertiary section under Lompoc Valley
is apparently a flat, voidisturbed but broadly warped synclinal area.
Orcutt sand is exposed around the valley but w^ater wells in the level
portion of the valley encounter fossiliferous sands of the Careaga below
terrestrial deposits at a depth of about 175 feet. Monterey shale is
exposed over a large part of Burton Mesa, which is a broad anticlinal
upwarp, and along the shore line northward from Surf. This upwarp
comprises many gently undulating folds with axes trending on the
average N. 75° W.
The Lompoc Valley-Burton Mesa area is apparently a broad, wedge-
shaped area widening seaward, of Franciscan rocks whose structure is
unknovm, covered by a thin blanket of middle and late Tertiary and Qua-
ternary sediments. This block was apparently stabilized by pre-Monterey
orogenies so that it resisted deformation and uplift during the great
Pleistocene orogeny, and therefore remained as a very slightly disturbed
lowland area. It extends an unknown distance out to sea, but to the east
wedges into the narrow Santa Rita and low^er Santa Ynez Valleys, which
geologically form a part of it.
Lompoc oil field is located on a large, broad, closed anticline devel-
oped along the northeast edge of the Lompoc lowland wedge. This fold
is not exposed at the surface, but eastward it becomes part of the Pur-
isima anticline which emerges from under the Careaga sand. "Wells
encounter Franciscan below the Monterey shale at a depth of about 3000
feet under the Lompoc anticline. The fold is asymmetrical, the south flank
dipping 5° to 10°, and the north flank about 30°. The dip increases with
depth on the north flank due to the great thickening of the Sisquoc
formation doAvn dip.
Santa Rita Valley and Lower Santa Ynez Valley
The structure of the Santa Rita and lower Santa Ynez Valleys is a
broad syncline with Orcutt and Paso Robles formations exposed on the
surface, and the axis trending about N. 75° W. This synclinal valley area
is structurally the eastward extension of the thin-blanketed Lompoc low-
land high, and has like it resisted Pleistocene deformation and uplift.
1950] STRUCTURE 59
Purisima Hills
The Purisima Hills are structurally an anticlinal uplift developed in
a thick late Tertiary-Quaternary section. This uplift has been formed
alorn? a belt where the section thickens northward from the thin-blanketed
Lompoc-Santa Rita-lower Santa Ynez Valle}' high on the south, to the very
deep, thick-blanketed synclinal trough on the north which follows Los
Alamos and upper Santa Ynez Valleys. As a result of this condition the
anticlinal structure of the Purisima Hills is generally asjTnmetric; the
south flank dips gently, and the north flank dips steeply or is even locally
overturned toward Los Alamos Valley.
The main axis of the Purisima anticline trends about N. 75° W. and
roughly follows the crest of the hills. The structure is highest in the east-
ern Purisima Hills, where Monterey cherty shale is exposed in the core,
and Sisquoc and Careaga formations on the flanks. Numerous minor folds
with axes trending about X. 75^ W. are developed in the Monterey shale
exposed in this area. The highest of these appears to be the one north of
Buellton where the Frank Buttram Xo. "Reuben" 1 well passed from
Monterey shale directly into serpentine at 1400 feet. In the extreme east-
ern Purisima Hills the anticlinal structure in the ]\Ionterey shale is over-
lapped by the Careaga sand and later formations, but is believed to plunge
eastward under Santa Ynez Valley. Southeast of the town of Santa Ynez
another fold emerges and rises eastward beyond the area mapped. A well
("X^ational Exploration Co.") drilled on this fold just east of Los
Olivos quadrangle reportedly bottomed in serpentine below Monterey
shale at 2665 feet.
The high portion of the eastern Purisima Hills plunges westward
into a saddle at Cebada Canyon. From here the axis in the pre-Careaga
formations extends westward and rises into the concealed Lompoc anti-
cline of Lompoc oil field. However the axis in the Careaga sand does not
conform to this fold, but extends northwestward and rises into a sharp
secondary anticline which exposes Sisquoc shale north of Lompoc field.
This fold, referred to as the western Purisima anticline is closed, partly
overturned and perhaps thrust-faulted southward. ]\Ian3^ wells drilled on
this structure find tliat it dies out at depth into the north flank of the
Lompoc anticline.
Faults in the Purisima Hills. The western Purisima anticline
appears to be cut by a small thrust fault that dips north. Evidence of this
fault is suggested by the highly sheared and brecciated condition of the
Sisquoc diatomite along the south edge of the hills hwe. and also by a
zone of shearing at 2200 feet in Union Oil Company X'o. ''Purisima" 19
well. Farther southeast are two small thrust faults that dip north at
Purisima and Cebada Canyons. The westerly of these dips 45° X. with
about 75 feet displacement. The easterly appears to be steeper, with about
100 feet of movement.
All three of these minor thrusts line up and appear to have developed
where the section thickens rapidly northeastward.
Los Alamos Valley and Upper Santa Ynez Valley
The structure underlying Los Alamos and upper Santa Ynez Valleys
is a major synclinal trough, the axis of which trends about X. 65° W.. and
passes through the towns of Los Alamos and Los Olivos. This downwarp is
referred to as the Los Alamos s^Ticline and forms the axis of the Santa
]Maria structural basin through the mapped area. It is a true synclinal
60 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
downwarp made up of a continuous series of sediments Miocene to Pleisto-
cene in age, which total some 15000 feet in thickness.
Along this sj^nclinal trough the warped depositional surface of the
Paso Robles formation is still preserved in eastern Los Alamos Valley and
eastern Santa Ynez Valley.
San Rafael Foothills
In the San Rafael foothills, an area of gentle uplift, the Paso Robles
formation is exposed and much dissected by erosion. The structure com-
prises two major anticlines, separated by a shallow syncline. The western-
most anticline is the Zaca, a very extensive, closed fold whose axis trends
about N. 60° W. for more than 12 miles. The Zaca oil field is at its highest
portion. Surface dips are about 15° on the south flank, 5° on the north
flank. The easternmost anticline is the San Marcos, whose axis trends
about N. 50° W. across Figueroa Canyon for some 15 miles, of which 6
miles lies within Los Olivos quadrangle. Northeast of this anticline is a
syncline whose northeast flank is largely concealed under the Little Pine
overthrust. These two folds are believed to cancel each other on the north-
west under the Little Pine overthrust near Figueroa Canyon.
Wells drilled throughout the San Rafael foothills find that the struc-
ture in the Careaga and Sisquoc formations conforms with the surface
structure of the Paso Robles formation. However, that of the Monterey
shale does not conform, but generally dips more steeply to the southwest as
it is overlapped from southwest to northeast by the Sisquoc, at least under
the Zaca anticline. Local folds also complicate the Monterey structure so
that details are not known. The Monterey shale is underlain by Cretaceous
(?) shale and sandstone in this area. Wells drilled on the San Marcos anti-
cline at Santa Aqueda Canyon pass from Sisquoc directly into Cre-
taceous ( ?).
San Rafael Mountains
The small portion of the San Rafael Mountains lying within Los
Olivos quadrangle is composed of Franciscan rocks and sill-like masses of
serpentine, striking due west to N. 60° W., and generallj^ dipping steeply
to the north. The Franciscan rocks may contain small sharp folds, but are
so highly sheared and brecciated that it is not possible to work out struc-
tural details. In the northeast corner of Los Olivos quadrangle the Fran-
ciscan is overlain directly by Monterey shale that dips steeply to the
northeast.
The Franciscan mass of the San Rafael Mountains has been thrust
southwestward along the Little Pine fault over the Paso Robles formation
of the San Rafael foothills. This fault dips from 25° to 38°NE at the
surface. Southeast of the mapped area this thrust fault is traceable for
some 20 miles along the base of the San Rafael Mountains. It extends
about 8 miles through Los Olivos quadrangle and dies out into upturned
Sisquoc and Careaga formations immediately northwest of Birbent
Canyon.
GEOLOGIC HISTORY
Jurassic Deposition. The earliest geologic event recorded in south-
western Santa Barbara County is the rapid deposition under a widespread
sea of the Upper Jurassic ( ?) Franciscan formation. This series of sands,
muds, siliceous cherts and basaltic lava flows attained an unknown but
tremendous thickness. Deposition of the Franciscan was followed by
deposition of the Honda shale, at least in the Point Arguello area.
^g.Qi GEOLOGIC HISTORY
in southwestern Santa ^^^ .^^H^Kmations, and the
ated condition of .^ot^^^^l^^/''!''^''Xono-hout the former. Neither for-
numerous serpentinized J^^^^^^Jd S^P^^'^°^*^ ^' ""'^ °''"
mation, however, was ^^tamorphosed .The^^^^^ disturbance occurred
erally affected m this manner, ^^f^J.^^^'^", "^^^ deposition of the
after deposition of the Honda, and probably be^^^^ ^^^^^
Espada shale. The shearing and brecci^^^^^^^^^^
tectonic forces, but may have ^^^^^^he ^e.ult^^^^^ ^^^^^^.
and their subsequent physica ^f P^^^^^^/^^^^',^^^ whether or not
tion to serpentine. The record is too .^^f^^T^^? J^^^'L^^e The Franciscan
the region emerged from the sea ^^^ ^^^^^^^^^^^^^^^^ after deposi-
^\^r:^^:i^^t1S^=^~- ^eat Nevadan
""'^'Taie Jurassic-Early Creiaceo^.Be,osiHonJ^^^^^
tion was followed by eonthW ^^^^ ^l ^^l^: Z^. A
area below sea level. A f.^^^^^^^^^'^':;'^?^ during the close of Jurassic
sands, the Espada ^rmation,. accumula^ec^^^^^^^^^^^ abundant, as indi-
and throughout early Cretaceous time Plant le .^^^^^ ^^cal
cated by the great amount of ^^^^^^^^^^.^^^'^^^^^^^ deposition of
intrusion of ultrabasic rocks ^^y/^!,^,'^^''^j4^Sees of serpentine in the
the Espada, as suggested by the l^f^^^^Xcas Canyon.
lower portion of the Espada formation m San ^^«^«;^^^4,,,^, record
in the mapped area is not cleaJ^^%^*f J^^^^^f Cm^^^^^^ However the
not this period is represented ^^ ^J^^f/jf^/^/.^'^ation suggests that
dence continued along the site of the S^^t J,^^ ^^^^^^^ This sea
became the northern part of the ^.^fj^ :^^\";;^g ^l,ieh constitute the
received some 3000 feet of ^'^'^'^'^ ^^J^Zl^^^^
Jalama formation. The absence of ^^is formation nortn ^.^^_
Mountains suggests that area was ^-^^^-^^Xmconformity between
Early Eocene ^^/^rmaf^ort^ The i^ lo ^^.^^ ^^^^^
the Cretaceous 3^\^}^^-f'l^^.l^^^^^^^ the northern portions
(or Sierra Blanca limestone where present J d undergone a
^f the Santa Ynez Mountains indicate^ dtinf earYv Eocene time. This
period of emergence, uplift^ TlTresuU of the^-reat Laramide orogeny,
Lturbanceisappajttytbe^^^^^^^ ^^^^ affected includes
active at the close of <^^^).^'^^'''l^ "^^^^^^
not only the northern portion of the ^anta Y nez ^ ^^^.^ ^^^ ^^^
can best be studied, but ^^.^Vln^i^^e Xctld area is referred to by Reed
a Op. cit., p. 13, fig. 6.
62 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Miocene. Its southern margin, the site of the northern Santa Ynez Moun-
tains, appears to have underoone a regional tilt to the south. The Santa
Barbara embayment was unaffected.
Eocene-Oligocene Deposition. From middle Eocene through early
Oligocene (Refugian) time, what is now the Santa Ynez Mountains sub-
sided continuously in the region of the Santa Barbara embayment, in
which was rapidly deposited a continuous series of sands, silts, and clays
making up the Anita, Matilija, Cozy Dell, Sacate, and Gaviota formations,
which attained a total maximum thickness of about 7500 feet.
During late Oligocene (late Refugian) time sedimentation graduall}^
exceeded subsidence in the Santa Barbara embayment so that it became
filled with sediments, causing partial regression of the sea. Terrestrial
sands and red silts of the Sespe formation were deposited in the eastern
portion, which formed a level plain. The area to the west remained sub-
merged under very shallow water, in which were deposited littoral sands
of the Alegria formation. Maximum thickness of the Sespe-Alegria sedi-
ments amounts to about 2000 feet.
The sediments deposited during Eocene-Oligocene time were derived
mainly from granite and metamorphic rocks, probably from an area to the
east, as indicated by their mineral composition and the predominance of
pebbles of granitic and quartzitic debris. Franciscan debris was deposited
in only very minor amounts, although it makes up a large part of the Sespe
conglomerate and red beds deposited in the Alisal-Nojoqui area along the
southern border of the rising San Rafael uplift.
Oligocene Deformation. "While the Sespe and Alegria formations
Were being deposited in the Santa Barbara embayment, the San Rafael
uplift underwent renewed deformation, uplift, and erosion. This dis-
turbance, the Ynezan orogeny, probably reached its climax at the close
of Refugian or beginning of Zemorrian time. The San Rafael uplift, or at
least that portion now occupied by Burton Mesa and the Purisima Hills,
rose to a rugged area exposing the Franciscan, which became the source
of the Sespe-Vaqueros conglomerates deposited along the southern border.
The effects of the Ynezan orogeny can best be studied along the
northern Santa Ynez Mountains, where sediments deposited along the
northern margin of the Santa Barbara embayment become involved.
Here the Gaviota and older formations became compressed into broad
gentle folds with axes trending slightly north of west, and near the site
of Tranquillon Peak some faulting occurred. This is the earliest definite
record of folding and faulting in the Santa Ynez Mountains. This defor-
mation was accompanied by emergence, uplift, and erosion.
Early Miocene Deposition. In Zemorrian (early Miocene) time
during or immediately following the Ynezan orogeny terrestrial sedi-
ments derived from the Franciscan San Rafael uplift were deposited in
the Nojoqui-Alisal area. These make up the Sespe conglomerate and red
beds of thatarea. Submergence of the entire northern Santa Ynez Moun-
tain area under a shallow sea transgressing northward from the Santa
Barbara embayment immediately followed. In this advancing sea was
deposited coarse gravel, then sand, of the Vaqueros formation, followed
by fine muds of the Rincon formation as the sea deepened in Saucesian
(early Miocene) time.
The San Rafael uplift was not submerged during Zemorrian-Sauce-
sian time but it contained at least one inland basin which received terres-
trial sediments of the Lospe formation.
1950] GEOLOGIC HISTORY 63
Early Miocene Deformation. In the very late Saucesian (late early
Miocene) time another disturbance, the Lompocan orogeny, affected the
San Rafael uplift, causing- renewed uplift, deformation, and erosion.
The Lompocan orogeny involved essentially the same portion of the Santa
Ynez Mountains as that affected by the preceding Ynezan orogeny,
especially the portion from San Julian Valley westward. Here folds devel-
oped during the former orogeny became further compressed during the
latter and involved the Vaqueros-Rincon formations.
The Lompocan orogeny and its forerunner, the Ynezan orogeny,
are extremely important in the geologic history of the mapped area and
perhaps of California, as they brought about a great change in. paleo-
geography. The Lompocan orogeny is especially significant as it vi'as
immediately followed by local volcanism, regional submergence, and a
great change in sediriientation.
Early Miocene Volcanism. Near the end of Saucesian time the
Lompocan orogeny was immediately followed by volcanic eruptions of
rhyolite lava, agglomerate, and ash at the site of Tranquillon Mountain,
and by local eruptions of basalt lava and agglomerate at the site of the
Santa Rita Hills. These volcanic and pyroclastic rocks make up the Tran-
quillon formation and were probably erupted as the region subsided fol-
lowing the Lompocan orogeny.
Middle and Late Miocene Deposition. The Tranquillon volcanism
was accompanied or immediately follow^ed by submergence of the San
Rafael uplift, so that throughout Relizian, Luisian (middle Miocene)
and Mohnian (late Miocene) time the entire mapped area was under
the sea which flooded a large part of California. In this widespread open
sea deposition of clays continued in early Monterey time but in decreas-
ing quantities as the nearby laud areas became submerged. Calcium
carbonate was deposited to form the limestones of the lower Monterey.
The Monterey sea receiA'cd enormous quantities of siliceous sediment,
deposited either organically or chemically. All these fine sediments must
have accumulated very slowly in the open sea at a depth below wave
and current action.
Marine life, particularly single-celled organisms, flourished during
Monterey deposition, and their remains make up a large part of the
Monterey formation. j\Iuch organic debris settled to the bottom and,
perhaps because of the great depth of the sea, was not oxidized. It con-
sequently became buried with the fine sediments, to form petroleum and
other bituminous matter.
The sea floor subsided at a more or less uniform rate and received
an average of about 2000 feet of Monterey sediments. However, subsid-
ence and deposition became unusually rapid along Los Alamos trough,
which began to develop as a do^^iiwarp, and received at least 4500 feet
of Monterey sediments.
Late Miocene Deformation. Deposition of the Monterey formation
was followed \)j a local but important disturbance, the Raf aelan orogeny,
which affected the area northeast of the Santa Maria-Los Alamos trough
and part of the San Rafael ^Mountains in Delmontian time. The result
of this orogeny is most evident in the Santa ]\Iaria Valley oil field, as
indicated by the northward overlap of the Sisquoc formation upon the
Monterey and Franciscan. A similar condition generally exists south-
eastward through the San Rafael foothills, as indicated by weUs, from
which it is evident that this area underwent emergence, uplift, and
64 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
erosion by being tilted regionally to the southwest. Some local folding-
may have occurred. The Rafaelan orogeny thus has affected the old San
Rafael uplift, but only the axial portion of it. Other areas throughout ''
the region mapped were undisturbed, except for slight local uplift at
the site of the Santa Rita Hills and southern Santa Ynez Mountains. fli
In the Santa Rita Hills the unconformity at the base of the Sisquoc
formation and consequent overlap of the upper Monterey shale indicate
this area to have undergone local uplift and erosion. Evidence that the
earliest uplift along the site of the southern or higher Santa Ynez Moun-
tains occurred during the Rafaelan orogeny is suggested by the breccia
conglomerate containing Monterey chert pebbles at the base of the Sisquoc
shale west of Gaviota Beach. (ji
Late Miocene-Pliocene Deposition. The Rafaelan orogeny was fol-
lowed by deposition of fine sediments of the Sisquoc formation during
late Miocene and early Pliocene time. Subsidence and deposition were
continuous and rapid along the Los Alamos trough, which received some
5000 feet of Sisquoc diatomaceous mudstone. Northeastward from this
downwarp, the Sisquoc sea transgressed onto the San Rafael axis which
gradually became buried by diatomaceous clay and silt. %
During late Miocene (Delmontian) time, the sea between the Los
Alamos trough and what is now the southern Santa Ynez Mountains
received about 1000 feet of lower Sisquoc diatomite. This sediment is
made up almost entirely of diatom tests, indicating a local condition
extremely favorable for very rapid propagation of diatoms. The very
low percentage of clastic material in this finely laminated diatomite
indicates deposition in protected waters, and fish remains found in these
sediments are mainly shallow-water species. The diatomite of the lower
Sisquoc was apparently deposited in a shallow, protected area of the
lower Sisquoc sea ; sheltered perhaps by the local uplift developed during
the Rafaelan orogeny along the site of the southern Santa Ynez Moun-
tains which may have persisted through late Miocene time either as a
very low island or peninsula, or more likely as a submarine ridge. South
of this uplift, clay and minor amounts of siliceous sediment accumulated
under an open sea.
During early Pliocene time, open seas probably existed throughout
the mapped area, in which were deposited clay, silt, and diatom debris of
the middle Sisquoc. Near the end of early Pliocene time, diatomite of the
upper Sisquoc was deposited in the Purisima Hills-Burton Mesa area.
In middle Pliocene time, subsidence continued in at least the west-
ern portion of the Los Alamos trough, which received about 1000 feet of
claystone of the Foxen formation. There is no record of deposition else-
where in the mapped area during this time interval.
Late Pliocene Deformation. In late Pliocene time, following or
perhaps accompanying deposition of the Foxen mudstone, most of the
area mapped underwent a great regional disturbance, the Zacan orogeny,
indicated by the widespread unconformity at the base of the Careaga
sand. This is best seen in the eastern Purisima Hills where the Careaga
sand laps over the eroded surface of the Sisquoc and Monterey forma-
tions. During the Zacan orogeny the entire region, with the exception of
the Los Alamos trough and San Rafael foothill area, underwent wide-
spread deformation, emergence, and erosion. Both the San Rafael and
1950] GEOLOGIC HISTORY 65
Santa Ynez I\ronntains came into existence by emergence and uplift along
lines of structural weakness wliich evolved into the present major faults
in these ranges. The folds formed in the northern Santa Ynez Moun-
tains during the Ynezan and Lompocan orogenies were further com-
pressed, and the Monterey-Sisquoc formations became involved in many
new folds with similar trends. The Burton ]\Iesa and eastern Purisima
Hills emerged as anticlinal uplifts.
Late Pliocene-Pleistocene Deposition. The Zacan orogeny was fol-
lowed by submergence of the entire Santa Maria Basin, with the excep-
tion of Burton ]\Iesa, in late Pliocene time, under a shallow emba^^uent
in which was deposited the Careaga sand. Subsidence and deposition were
most rapid along the Los Alamos trough.
Toward the end of Pliocene time the Santa ]\Iaria Basin became
filled with sediments, causing the sea to withdraw, and became a broad
plain on which terrestrial sediments of the Paso Eobles formation were
deposited. These were derived from the rising San Kafael and Santa Ynez
Mountains, and became increasingly coarse as these ranges grew during
the Pleistocene.
The Paso Eobles sediments were derived mainly from the San Rafael
Mountains, and deposition of these alluvial sediments was especially
rapid along the foot of this range where the formation attains a thickness
of more than 4500 feet. It progressively thins away from this mountain
front. This appears to be a case in wliich the weight of rapidly deposited
sediments actually caused subsidence of the underlying platform.
Pleistocene Deformation. The increasing growth of the San Rafael
and Santa Ynez ^fountains culminated in the early Coast Range orogeny
in the middle Pleistocene, when these ranges probably attained their
present heights. This great orogeny affected the entire mapped area,
causing further compression of folds formed by earlier orogenies, and
the development of many other structures, in which the Careaga and
Paso Robles formations were involved. The Purisima Hills and San
Rafael foothills were formed during this disturbance by anticlinal
folding.
The mountains and hills formed during the early Coast Range
orogeny underwent intensive erosion which is referred to as the ''first
erosion cycle." This is described in detail under the section headed
Erosion Cycles.
The late Pleistocene was a period of relative quiescence, during
which the elevated areas were worn doT\Ti to the late mature stage of
erosion and sands of the Orcutt formation were deposited in Lompoc and
Los Alamos Valleys, and terrace gravels in Santa Ynez Valley and on the
coastal plain.
The region underwent renewed deformation and uplift in very late
Pleistocene and Recent time when it attained its present topography.
This disturbance is termed the late Coast Range orogeny; during this
time the area underwent the "second erosion cycle," as described under
Erosion Cycles.
The complex structure and resultant physiography of Santa Bar-
bara County were developed by the series of diastrophic events starting
with the early Miocene Ynezan orogeny and culminating with Pleis-
tocene Coast Range orogeny, caused by a recurrent stress system of
increasing intensity, these events together constituting the local effect
of the Cascadian revolution.
66
SOUTHWESTERN SANTA BARBARA COUNTY
Bull. 150
CONTOURS ON TOP OF
VAQUEROS ZONE
• WELL COMPLETED
> WELL COMPLETED, ABANDONED
^ WELL UNCOMPLETED, ABANDONED
Figure 6. Structural map of Capitan oil field, Santa Barbara County.
1950] MINERAL RESOURCES 67
MINERAL RESOURCES
Oil and Gas
Within the quadrangles mapped oil and gas have been found both
in the Santa Barbara-Ventura Basin and in the Santa Maria Basin. The
former jdelds high-gravity oil and considerable gas from sands of the
Vaqueros, Sespe, and Eocene formations in closed structures along the
southern coastal area between Capitan and Point Conception. The latter
basin yields low-gravity oil from fractured siliceous shale of the Monterey
formation in closed structures in the Purisima Hills and San Rafael
foothills.
The intermediate areas between the two stratigraphic basins, namely
the coast north of Point Conception, Santa Ynez Mountains, Santa Rita
Hills, Burton Mesa, Lompoc and Santa Ynez Valleys, and southeastern
Purisima Hills have failed to yield oil or gas. Throughout these areas are
many closed anticlines exposing Monterey shale at the surface. Wells
have been drilled on nearly all of these structures to test the lower Mon-
trey shale and the underlying lower ^Miocene or Eocene sands, but all
were dry holes, generally without showings. The results of exploratory
wells drilled throughout these areas are indicated in the accompanying
tables (see pp. 70-74).
Santa Barbara-Ventura Basin
Capifan Oil Field. The subsurface structure of the Capitan oil field
is an anticlinal dome closed by drag against the north-dipping Erburu
fault. This structure is not apparent on the surface, as the Erburu fault,
which in part limits production on the north, crops out through the
southern portion of the field and is paralleled on the north by a syncline
in Mouterej' shale.
Since its discovery in 1929 the Capitan field has produced more
than 11,000,000 barrels of 16° to 43° gravity oil from an area of 296
acres. Oil is produced from the Vaqueros sandstone at a depth of from
1000 to 1400 feet below sea level, and also from two zones in the upper
Sespe : the Erburu 8 zone and Erburu 10 zone. The upper Sespe also
contains a gas zone. Deeper drilling since 1945 has resulted in the dis-
covery of large flowing wells, from the Covarrubias zone of the lower
Sespe, and the Eocene zone at the top of the Gaviota-Sacate ("Cold-
water") formation, which have greatly augmented the reserves of this
field.
The Vaqueros zone was discovered by General Petroleum Corpora-
tion's No. "Erburu" 1 well in 1929. The Vaqueros sand produces from
100 to 600 barrels per day of 20° A.P.I, gravity oil.
The Erburu 8 zone of the upper Sespe was discovered by General
Petroleum Corporation's Xo. "Erburu" 8 well, completed in January
1931 for 250 barrels per day of 40" to 42° gravity oil. This sand is 125
feet thick, is topped at 660 feet below the top of the Sespe, and produces
125 to 1000 barrels per day of oil. The Erburu 10 zone is 75 feet thick, is
topped at 1000 feet below the top of the Sespe, and produces 100 to 600
barrels per day of 44° gravity oil.
The Covarrubias zone was discovered by Shell Oil Company's No.
"Covarrubias" 1-35, completed February 1945 flowing 1375 barrels per
day of 39° gravity oil from the interval 3355-3637 feet in the lower Sespe.
68 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
The Eocene or "Coldwater" zone was discovered by Shell Oil Com-
pany's No. " Covarrubias " 1-36, completed August 1945 flowing 520
barrels per day of 39° gravity oil from the interval 3805-3825 feet from
uppermost marine Oligocene-Eocene (Gaviota or "Coldwater") sand-
stone.
As of January 1, 1948, Capitan field had 66 producing wells, of
which 8 were flowing, 57 pumping, and 1 shut in. Cumulative production
to that date was 11,897,000 barrels.
The geology of Capitan field is described in detail b}^ Dolman ^^ and
Kribbs.^3
Befugio Cove Area. At the mouth of Refugio Canyon is a large
closed anticline in Monterey shale. Rincon shale is exposed on the crest
of the fold at Refugio Cove. The first test well. Shell Oil Company No.
"Rutherford" 1, drilled in 1928, found both Vaqueros and Sespe sands
devoid of oil, and was drilled far into the Gaviota-Sacate (" Coldwater")
formation which flowed dry gas and sulfur water. Since the deep test
many other wells have been drilled on this closed structure, but none has
obtained commercial production except Rothschild Oil Company No.
"Orella" 1 which discovered the small Refugio gas field.
Befugio Gas Field. The Refugio gas field occurs on a small closed
anticline in Monterey shale within the Refugio dome about a mile west
of Capitan field. The discovery well, Rothschild No. "Orella" 1, drilled
in 1946, flowed at an estimated rate of 5.000.000 cubic feet of gas per day
from the Vaqueros sandstone at about 2500 feet. To date this field con-
tains three gas wells.
Drake Area. Near Drake station, at the mouth of Caiiada Santa
Anita, is a syncline on shore and a supposed anticline off shore in Sisquoc
shale with axial planes hading northward. The first test well, Western
Gulf No. "Hollister" 1, drilled in 1928, drilled into the Vaqueros sand-
stone at 3088 feet and blew in out of control, producing an estimated rate
of 25,000,000 cubic feet of gas per day. After the well Avas brought under
control, it produced a few barrels of light oil and considerable salt water.
The gas flow soon died down and after all attempts to shut off the water
failed, the well was abandoned. Several other test wells were drilled on
this structure, but all failed to obtain commercial production.
Point Conception Area. The north-dipping homocline in the Point
Conception area is the possible north flank of a large off-shore anticline.
This structure was tested in 1930 by Standard Oil Company No. ' ' Ger-
ber" 1 at Government Point. This well found some gas and salt water in
the Vaqueros sandstone, was drilled through the Alegria, Gaviota, and
Sacate formations and encountered good shows of light oil in tight sands
of the Sacate ( ? ) . After all tests failed to obtain production, the well was
abandoned.
Santa Maria Basin
Lompoc Field. Union Oil Company, which discovered Lompoc field
in 1903, controls the major part of it and developed it in a conservative
way until 1940. As of that date, the field produced 7,900,000 barrels of oil
from 49 wells from an area of about 2200 acres. However, since 1942 this
field has undergone renewed and more thorough development, due to
B2 Dolman, S. G., Capitan oil field : California Div. Oil and Gas, Summary of Opera-
tions, California Oil Fields, Kept. 24, no. 2, pp. 15-26, 1938.
63Kribbs, G. R., Capitan oil field: California Div. Mines Bull. 118, pp. 374-376,
1943.
1950] MINERAL RESOURCES 69
heavy demand for oil since the last war. Wells have been drilled at the
rate of about two per month. The new wells completed have greatly
increased production of the field, but the acreage has not been appreci-
ably extended, as outpost wells are structurally too low and fail to obtain
production. The field has produced 14,601,000 barrels of oil to January 1,
1948. On that date, production was from 77 wells, of which 6 were flow-
ing, 67 pumping, and 4 shut in.
Lompoc field produces 15° to 24° A.P.I, gravity oil from fractured
siliceous (only slightly cherty) shale of the upper Monterey, at depths
from 1900 to 2200 feet below sea level. Production is from the western
Purisima anticline which is closed and made up of at least two closed
anticlines en echelon, separated by a syncline which is probably faulted
near the axis. The geology of Lompoc field has been described in detail
by Dolman ^* and Dibblee.^°
Purisima Hills. Many test wells have been drilled throughout the
Purisima Hills but with the exception of Lompoc field no commercial
production has been obtained. Wells drilled in the central portion of the
Purisima Hills were dry holes, as the structure of this portion is a saddle
in the Purisima anticline. The eastern portion contains several closed
anticlines exposing Monterey shale ; these were tested, but the Monterey
is here underlain by Espada or Franciscan and no oil was found. The
south flank was tested by Richfield Oil Corporation No. ' ' Skytt" 1 drilled
to 6007 feet and abandoned without showings.
Wells drilled on the north flank of the Purisima Hills found the
Sisquoc too thick to penetrate, although the Monterey was reached on an
anticline across Santa Ynez Canyon where some heavy oil was found in
Whittier Associates No. "Barham" 1. This well produced about 78 bar-
rels of oil per day from fractured cherty shale of the Monterey at 4000
feet. No. "Barham" 2 was a dry hole, but No. "Barham" 3 obtained
small production. These wells are not commercially productive.
Zaca Field. The discovery of Zaea oil field was made in 1942 by
Tidewater Associated Oil Company, when its No. ''Davis" 1 well was
brought in pumping 294 barrels of 7° gravity oil including 37 barrels
of distillate, 33 percent emulsion from Monterey cherty shale, at 4465
to 5956 feet. The well settled to 150 barrels per day, 7° gravity clean oil.
Tidewater Associated Oil Company, which controls the field, has been
developing it in an orderly way and to date has 10 producing wells. The
field produces a moderate amount of oil averaging 8° gravity, which is
so viscous that distillate must be injected in order to render the tarry
oil fluid enough to pump out. As of January 1, 1948, Zaca field had pro-
duced a cumulative total of 358,000 barrels of 8° to 10° A.P.I, gravity oil
from these wells.
The structure of Zaca field is a large closed anticline in the Sisquoc
and overlying formations, and the oil is produced from fractured cherty
shale of the Monterey which here unconformably underlies the Sisquoc.
Detailed structure of the Monterey is not known, but is regionally a
homocline dipping southwest, and the oil occurs in the cherty shale where
it is overlapped by the Sisquoc.
"Dolman, S. G., Lompoc oil field, Santa Barbara County, California: California
Div. Oil and Gas, Summary of Operations, California Oil Fields, Rept. 17, no. 4, pp.
13-19, 1932.
» Op. cit
70
SOUTHWESTERN SANTA BARBARA COUNTY
[Bull. 150
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1950] MINERAL RESOURCES 75
Asphalt
Four deposits of asphalt in the form of tar-impresmated sands occur
in the area mapped, one on the south coast and three in the Purisima
Hills. None has been quarried.
Along: the sea-cliff within 1^ miles west of Gaviota Beach are five
exposures of chert pebble eonelomerate and sand ; and one exposure on the
south face of a hill 2 miles west, in which the sand is well impregnated with
asplwilt. This conglomerate probably form.s the base of the Sisquoc
although some occurs in the upper ^lonterey. It attains a maximum
exposed thickness of about 50 feet and dips about 45° S. Thin lenses of
this conglomerate also crop out east of Cuarta Canyon and at Sacate
Canyon.
In the eastern Purisima Hills is a large deposit of tar-soaked sand
at the base of the Sisquoc on the west .side of the canyon 1^ miles north
of Jonata Park. ThLs deposit consists of very fine sand heavily impreg-
nated with asphalt. It is about 75 feet in maximum thickness and extends
about a mile, dipping steeply north into a syncline. This tar sand grades
laterally along the strike into oil shale.
Redrock ^Mountain in the central Purisima Hills is formed by a
large depo.sit of tar-soaked sand. This consists of fine sand of the Careaga
formation, is about 50 feet thick, and caps the mountain. The sand is
well impregnated with asphalt. Two erosional remnants of this tar sand
occur about 1 mile down the spur to the southwest. The tar sand of
Redroek Mountain is underlain by highly bituminous shale of the lower
Sisquoc which has locally been burned, causing it to become brilliant
red and locally scoriaceous.
A small deposit of tar sand occurs at Lompoc oil field in Purisima
Canyon. This consists of medium-grained Careaga sand impregnated
with asphalt. It is about 25 feet thick and dips gently south. At the
south end of Harris grade is exposed about 15 feet of basal Careaga (?)
tar sand lying uneonformably on Sisquoc diatomite.
Diatomite
The southern portion of the Santa 'MariR Basin is noteworthy for
its extensive deposits of diatomite. or diatomaceous earth. This is all of
marine origin, of upper Miocene and lower Pliocene age. and is confined
largely to the Sisquoc formation, except for local interbeds in the upper
Monterey shale. The diatomite deposits are developed in the Purisima
Hills. Santa Yuez Valley, and in the northern foothills of the Santa Ynez
^Mountains south of Lompoc Valley. In the last-named area it is remark-
ably pure and makes up the largest known diatomite deposit of com-
mercial value in the world, which contains the world 's largest diatomite
workings. Diatomite deposits of known and potential economic value
are shown on the economic maps.
Types of Diatomite
The diatomite of the Sisquoc and ]\Ionterey formations is of three
types: (1) pure thinly stratified: (2) impure coarsely stratified; and
(3) impure massive. The pure thinly stratified diatomite is of commercial
value and is marketed under the trade name "Celite." by Johns-Man-
ville Products Corporation. The impure diatomites are of little or no
commercial value.
76 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
The thinly stratified diatomite is soft, very light weight, porous, and
made up of laminae averaging about gV of an inch. It is coherent, but
tends to fracture along bedding planes, and is nearly pure white when
dry ; but below the .surface it is cream-colored and contains 50 percent
moisture. It is of such high porosity that it will absorb nearly 75 percent
water Avhen saturated. The material is made up almost entirely of well-
preserved siliceous tests of diatoms. These comprise more than 200 spe-
cies, but in general there are two types — disc-shaped diatoms, and fili-
form or needle-shaped diatoms. These occur in varying ratios in different
strata, but the disc types generally predominate. In addition to diatoms,
there are subordinate siliceous remains of animal life svich as radiolaria,
silicoflagellates, and sponge spicules. The thinly stratified diatomite
contains verj^ minor impurities such as flakes of volcanic ash and par-
ticles of clay, quartz, or amorphous silica.
The impure coarsely stratified diatomite consists of the above type
with as much as 10 percent admixture of clayey material. This diato-
mite differs from the thinly stratified type ; it is heavier and less porous,
and is cream colored when dry, and light brown when moist. The diatoms
are generally more broken. This type is rejected as waste.
The impure massive diatomite is also cream colored and contains
an admixture of clayey material ranging from a fraction of 1 percent
to 50 percent, beyond which it grades into diatomaceous claystone. It is
typically massive and breaks with conchoidal fracture. The diatoms are
generally broken and poorly preserved, and the material is somewhat
harder and less porous than the other two types.
Deposits South of Lompoc Valley
The hills south of Lompoc Valley and the western Santa Rita Hills
contain several deposits of high-grade commercial diatomite covering an
area of about 17 square miles. This diatomite is of upper Miocene age
and comprises the lower 1000 feet of the Sisquoc formation (assigned to
Monterey formation by Arnold and Anderson,^*^ and by Mulryan ^'^) , and
minor amounts are locally interbedded in the siliceous shale of the upper
Monterey formation. The upper Sisquoc in this area is of the impure
massive type and consequently of no economic value. The high-grade
lower Sisquoc diatomite crops out along the northern slopes of the Lompoc
and Santa Rita Hills, where it dips northward under Lompoc Valley.
Farther south in these hills the diatomite is largely eroded away, but is
preserved in several basin-like synclines where it is quarried.
The lower Sisquoc diatomite consists of alternating laj^ers of the
pure thinly stratified variety, and the impure coarsely stratified variety,
as previously described. Determination of the quality of the diatomite
requires much sampling and microscopic examination. Chemical tests
are required to determine the amount and kind of impurities. As the pure
diatomite occurs in certain strata, selective quarrying of these layers is
required. The lower Sisquoc diatomite is remarkably free of other rock
types. Layers of opaline chert seldom occur and these in beds only a few
inches thick. In some places the chert occurs as nodules or nodular layers.
Thin layers of volcanic ash are locally present. In the Santa Rita Hills the
base of the lower Sisquoc diatomite is locally marked by a layer of phos-
phatic pebbles or pellets, or by sand. At some places about a foot of lime-
^ Op. cit.
^■^ Mulryan, H., Geology, mining', and processing of diatomite at Lompoc, Santa
Barbara County, California : California Div. Mines Rept. 32, pp. 133-166, 1936.
1950] MINERAL RESOURCES 77
stone occurs near the base, bnt in most places the lower Sisqiioc diatomite
lies conformably on ]\Ionterey clierty shale, or grades down into it through
about 50 feet of beds.
Diatomite of the upper Monterey is similar to that of the lower
Sisquoc, except that it is interbedded with opaline and cherty shales.
Much of the diatomite is of high quality, but it seldom occurs in pure
beds more than 50 feet thick. The diatomites of the upper Monterey are
local phases of opaline cherty shale, into which they grade laterally. They
occur in the vicinity of Salsipuedes and San Miguelito Canyons, and also
in Espada Canyon.
Deposits of Purisima Hills and Santa Ynez Valley
The Sisquoc formation of the Purisima Hills is composed largely of
impure, coarsely stratified and massive diatomite, and is therefore of
little or no commercial value. However, in the eastern Purisima Hills
west of Zaca Creek, there is a small deposit of high-grade diatomite, con-
sisting of about 500 feet of thinly stratified diatomite in the uppermost
Monterey formation below the basal Sisquoc tar sand. This diatomite
occurs in a west-plunging syncline 1 mile north of Jonata Park, and also
on the north flank of the adjacent anticline to the north. The lower
Sisquoc also contains some thinly stratified diatomite 1 mile west of
Jonata Park. None of these deposits have been worked.
In Santa Ynez A'alley in the vicinity of Solvang is a small deposit of
pure thinly stratified diatomite occurring in the lower Sisquoc formation.
About 500 feet of diatomite is exposed and occurs in a sharp anticline
and s^aicline. The deposit was quarried and mined 1 mile northwest of
Solvang.
On the north flank of the anticline east of Santa Ynez are several
outcrops of stratified white diatomite about 1000 feet thick in the lower
Sisquoc formation. Some of this is of possible commercial grade. It is
largely concealed by terrace deposits.
Uses of Diatomite
To quote from ]\Iulryan ^^ :
"Briefly summarizing-, the principal uses of Celite Diatomite Prod-
ucts are: In insulation at comparatively high temperatures, also low tem-
peratures, building insulation, and filtration of all types of liquids from the
most viscous to the least viscous ; as admixtures and mineral fillers where
a chemically inert light-weight mineral is required, as a mild abrasive in
polishes, and a filler in paints."
Diatomite Quarries
Johns-ManviUc Qiiarrics. For a detailed description of the Johns-
Manville quarries, the reader is referred to Mulryan 's ^^ report in which
the geology of the diatomite deposit and the mining and processing
operations by the Johns-Manville Products Corporation are described.
These are summarized in the following abstract ^^ :
"The largest and purest known deposit of diatomite is being actively
mined and processed three and one-half miles south of Lompoc, Santa
Barbara County. California, by the Johns-Manville Corporation.
"The workings cover 4000 acres, the depth of economically recoverable
diatomite being 1000 feet.
58 0p. cit., p. 164.
59 Op. cit, pp. 133-136.
80 Mulryan, H., op. cit., pp. 133-134.
78 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
"These marine beds assigned to the Monterey formation, upper
Mioocne are generally soft, white, extremely porous, light weight, and of
remarkable uniformity and purity.
"The diatomite is quarried on the surface by gasoline and diesel-
powered shovels, and loaded into trucks which haul the material to vertical
storage shafts sunk in the diatomite. The diatomite is drawn off at the
bottoms of the holes into cars and hauled underground by electric trolley
locomotive to the jirimary crushing plant.
"The crushed crude is conveyed to mill bins and processed. Powders
for filtration, admixtures, mineral fillers, and insulation purposes are pro-
duced in the milling systems.
"Insulation brick are sawed directly in the quarries or produced from
aggregates and calcined in a tunnel or beehive kiln.
"The company maintains a complete machine shop, garage, electric
and carpenter shop, camp for employees, hospital, and a plant development
department at the deposit. A research staff is establislied at Manville, New
Jersey."
Concerning the diatomite deposit, Mulryan ^^ makes the following
statement :
"The company owns or controls an area comprising 4000 acres in the
main deposit. The diatomite contained therein is remarkable because of
its high degree of purity in this huge deposit. It is generally accepted as the
largest and purest known deposit in the world. Its great thickness, more
than 1000 feet, and its undisturbed condition, with the added benefit of
sufficient relief to permit easy mining conditions, certainly place the deposit
in a unique position."
The writer is not in complete agreement with Mulryan concerning
the geology of the diatomite deposit. Mulryan follows Arnold and Ander-
son ^^ in assigning the diatomite to tlie Monterey formation, but the
writer restricts only the diatomite interbedded with siliceous shales to
the Monterey, and assigns the overlying 1000 feet of homogeneous dia-
tomite to the Sisquoc formation, on the basis of regional mapping and for
reasons stated under Stratigraphy .
Mulryan ""^ states that the eastward-trending syncline containing
the diatomite deposit of Johns-Manville Products Corporation is a down-
faulted block, bounded on the northeast by a major cross-fault following
Salsipuedes Creek, and on the southwest by another in San Miguel
Canyon. The writer has found no conclusive evidence of such faults — at
least not on a major scale — and believes that the synclinal structure con-
taining the diatomite rises both east and west from the Johns-Manville
propert}^ forming a structural basin as indicated on the geologic map of
the Lompoc quadrangle.
Dicalitc Quarries. About 7 miles southeast of Lompoc is a large dia-
tomite deposit on the portion of Rancho San Julian owned by W. C. H.
Dibblee. This deposit was leased in 1942 to the Dicalite Company which,
since 1945, has been the Dicalite Division of Great Lakes Carbon Cor-
poration. The diatomite of this deposit is of high commercial value similar
to that of the Johns-Manville quarries; it covers some 1,500 acres and
contains an estimated 166,000,000 cubic yards of diatomite.
The diatomite of the Dicalite quarries is assigned to the lower Sis-
quoc formation and is the same in lithology and quality as that of the
Johns-Manville quarries ; it lies with sharp, but conformable, contact on
Monterey cherty shale. The diatomite occurs in a structural basin,
■ - ■ ■ - •
6iOp. cit.p. 141.
82 Op. cit.
esQp. cit., p. 139.
1950] MINERAL RESOURCES 79
similar to that of the Jolms-Manville deposit, composed of three syiiclines
separated by two anticlines. These folds trend about N. 85° W. and extend
abont 2 miles; dips vary from flat on the axes of the folds to 50° on the
flanks. The north vSyncline is the largest and contains diatomite to an
estimated maximum depth of 700 feet. The middle syncline contains dia-
tomite to about 500 feet maximum depth, and the south syncline to about
250 feet depth.
The diatomite of the Dicalite quarries contains occasional thin layers
of volcanic ash as at the Johns-Manville quarries. Some diatomite layers
carry many dark brown phosphatic lenticular concretions 1 inch to 2
inches in diameter and half an inch thick.
In 1943 the diatomite deposit w^as quarried by the Dicalite Company,
and in 1947 bj' Dicalite Division of Great Lakes Carbon Corporation.
The method used was surface quarrying and hauling by truck. Operations
at the deposit are still in the development stage, there being no under-
ground workings nor processing plant. The deposit has been prospected by
trenching and scraping of ridges by bulldozer, and by vertical holes 30
inches in diameter and about 50 feet deep.
Quarrying operations have been confined to the north syncline. Only
layers containing thinly stratified pure diatomite are quarried; asso-
ciated impure diatomite is dumped as overburden. In 1943 the high-
grade diatomite was quarried by power shovel, but during 1947 it was
quarried by carry-all. The quarried material is loaded onto dump trucks
which haul it to stock piles located adjacent to the main surfaced road.
From the stock piles the diatomite is moved by dragline to a loading chute
where it is loaded onto truck and trailer, covered by tarpaulin, and
hauled about 150 miles to the Dicalite processing plant located at Wal-
teria in the Palos Verdes Hills east of Palos Verdes, California.
Diatomite Quarry in La Salle Canyon. Five miles southwest of
Lompoc on the east side of La Salle Canyon, lower Sisquoc diatomite dips
steeply north. The plant is idle.
Diatomite Quarry Near Solvang. One and a half miles northwest
of Solvang lower Sisquoc diatomite dips generally south, but a small fold
is exposed. The plant is idle.
Limestone
Deposits of limestone occur at the base of the Monterey shale in the
northwestern Santa Ynez Mountains near Lompoc. Limestone crops out
on both sides of El Jaro Canyon below the juncture of Los Amoles Creek.
The limestone here is white, but weathers gray on the surface ; it is dense,
massive, and hard, but generally much fractured, breaking into irregular
pieces. The upper portion is limestone but the lower portion becomes
calcareous tuffaceous sandstone with local occurrences of conglomerate
at the base. Total maximum thickness aggregates about 150 feet; the
pure limestone has a maximum thickness of about 70 feet. Locally several
thin lenses of limestone occur in the overlying shales of the Monterey.
The structure of the limestone and overlying shales here is that of gently
undulating folds. The limestone forms many landslides, especially where
it is underlain by soft formations.
Between San Pascual and La Salle Canj^ons southwest of Lompoc
is a limestone bed of about 100 feet maximum thickness which dips
steeply north and is exposed for a distance of more than 2 miles, between
80 SOUTHWESTERX SANTA BARBARA COUNTY [Bull. 150
Monterey shale above and Tranquillon agglomerate below. The limestone
is similar to that of El Jaro Canyon, consisting of pure limestone grading
downward into calcareons sandstone.
The Miocene limestone of the northwestern Santa Ynez Mountains
has not been worked for cement, but at El Jaro Creek, 7 miles southeast
of Lompoc, it has been quarried and crushed for road gravel.
Southwest of Solvang the basal Monterey limestone is exposed along
the south bank of the Santa Ynez River for a distance of about three-
quarters of a mile, Avhere it dips steeply north. The limestone here is
impure and is made up largely of calcareous algae. It is quarried for road
material.
The Sierra Blanca limestone exposed in Nojoqui Canyon and at
several other localities in the Santa Ynez Mountains, is sandy and con-
tains calcareous algae. It was quarried at Nojoqui Canyon for road
material.
Bentonite
Thin beds of bentonite are locally developed at the base of the Mon-
terey shale or in the Tranquillon formation at various places in the Santa
Ynez Mountains. Several exposures occur between Gaviota and Cojo
Canyon on the south flank ; it is also exposed in Gijote Canyon and Llani-
tos Canyon. It is probably rhyolitic, as it is associated with rhyolite tuff
in Cojo Canyon. It has not been quarried.
Flagstone
Slab-rock suitable for flagstone has been quarried at two locations
in the western Santa Ynez Mountains. One of these is at the Golondrina
Dairy of Ranclio San Julian, on the highway 6 miles west of Las Cruces.
The rock was hand-quarried in 1929 by A. Dibblee Poett and sold to
private individuals. The rock-slabs occur in shale of the upper part of the
Sacate formation (Eocene) which here dips steeply north on a north-
facing hillside. The slabs average about 3 inches thick, are unusually
large, and consist of extremely hard, coherent, fine-grained sandstone.
They make excellent flagstones for garden-paths, steps, or stone floors.
The flagstones are confined to the upper shale member of the Sacate
formation, and are well developed along the strike some 2 miles to the
west on the divide between San Julian and Los Amoles Valleys, where
they dip gently northeast.
Flagstones were quarried at Tajiguas prior to 1942. These occur as
large slabs of hard, coherent calcareous and siliceous shale in the lower
Monterey shale, ranging up to a foot in thickness. The formation here
dips about 20° S., and is almost a dip-slope on a south-sloping hillside.
Road Gravel
Dihhlee Quarry. The Dibblee quarry is a large quarry on the north
side of El Jaro Canyon 7 miles southeast of Lompoc. It is on the W. C. H.
Dibblee property of Rancho San Julian and was worked occasionally
from 1928 to 1944 by the Santa Barbara County Road Department. The
rock quarried is basal limestone of the Monterey shale, which here dips
north into the hill. The limestone here is about 40 feet thick, grading
upward into brittle cherty shales. About 15 feet of conglomerate occurs
at the base of the limestone. The limestone and overlying shale are much
fractured. Quarrying is done by blasting and power shovel, and the rock
1950] MINERAL RESOURCES 81
is crushed into gravel of various sizes. It was used for surfacing the
Lompoc-Las Cruces road and other roads in the Lompoc area.
Alisal Quarry. The Alisal quarry is located on the south side of
Santa Ynez River 1 mile south of Solvang. The quarry is in basal lime-
stone of the ^lonterey shale, vrliich here dips very steeply north and forms
the south bank of the Santa Ynez River. The rock consists largely of very
hard light-gray algal limestone, about 50 feet thick. The basal portion
consists of calcareous and tuffaceous pebbly fossiliferous hard sandstone.
The quarri- was operated at various times by the county- between
1926 and 1941. by blasting and power shovel. The rock was crushed into
gravel of various sizes and used in surfacing roads in the Santa Ynez
Valley.
CaU(jon Quarry. The Callejon quarry is near Callejon Dairy of
Rancho Sau Julian, on the Lompoc-Las Cruces road. 4 miles west of
Las Cruces. The rock was first quarried in 1928 by the Santa Barbara
County Road Department, and again iu 1947-48 by the California Divi-
aon of Highways through X. TV. Ball and Son. contractor. The quarry is
in Taqueros conglomerate and sandstone which here is on end or slightly
overturned northward. The formation is about 300 feet thick. The rock
consists of basal pebble conglomerate with a brown clayey sandstone
matrix, grading upward into pebbly sandstone. The formation is soft and
easily quarried by bulldozer and power shovel. About 67.000 tons were
removed in 1947-48 and the material was used in resurfacing the highway
between Las Cruces and San Julian ranch-house gate.
Monterey Shale Gravel Quarries. Loose talus gravel of Monterey
cherty shale has been quarried at many places in the vicinity of El Jaro
Creek for use as road gravel. One of these is on the east side of El Jaro
Canyon 7^ miles southeast of Lompoc : another in Los A moles Canyon
half a mile above the junctiu-e with El Jaro Creek: one at El Chorro
Ranch, 9 miles southeast of Lompoc : and one about a mile up Yridises
Canyon.
All of these were quarried in 1928-30 by the Santa Barbara County
Road Department for use on the Lompoc-Las Cruces highway which was
being rebuilt at that time. Quarrying was done by steam shovel, and the
loose shale was loaded directly into trucks without treatment.
Buell Flat Bock Quarry. Just west of Solvang, Recent stream
gravel of the Santa Ynez River bed is quarried by the Buell Flat
Rock Company of Solvang. and is used mainly as road material. The
gravel is fairly clean and is quarried by power shovel, and sorted by
screening into various sizes from 2-inch to pea gravel.
Biver Quarry Xear Santa Bosa Pari-. Jn the Santa Ynez River bed
at the mouth of Drum Canyon near Santa Rosa County Park is a gravel
quarry operated by Cox and Chilson of Lompoc. The gravel is similar
to that of Buell Flat quarry and operations are the same.
Manganese Ore
A small deposit of manganese ore (pyrolusite or psilomelane) occurs
in the Franciscan formation of the San Rafael ^Mountains 7 miles north-
east of Los Olivos. The ore occurs as a somewhat lenticular mass roughly
20 feet thick in dark maroon ferruginous chert, dipping steeply north.
"Workings consist of an open shaft about 6 feet square and about 20 feet
deep. The prospect may contain a lower level but was not entered.
7—13966
82 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
This and another manganese prospect of little apparent value were
briefly described by F, S. Hudson as Santa Barbara County nian<?anese
deposit no. 2, La Laguna Rancho, in a recent bulletin by Trask and
others.^*
Water
Springs. In Santa Ynez Valley, immediately west of Santa Ynez,
a large artesian spring issues from terrestrial gravels. The volume is
sufficient for irrigation and was used for this purpose on the lands of
Mission- Santa Inez by the Franciscan Fathers who first settled in Santa
Ynez Valley.
The Santa Ynez spring is believed to issue from the saddle between
the east end of the Purisima anticlinal uplift and the large anticline
rising eastward from Santa Ynez. This gravel-filled gap between these
two uplifts apparently acts as the outlet for the underground water of
practically the entire drainage basin of upper Santa Ynez Valley, and at
this outlet the water gathers in such large volume as to reach the surface.
In the San Rafael Mountains numerous springs issue from serpen-
tine and landslide masses of the Franciscan formation. In the Santa Ynez
Mountains are many springs, which issue mainly from the following
formations in order of abundance : ( 1 ) Vaqueros pebble conglomerate ;
(2) Sespe conglomerate (Nojoqui-Alisal area) ; (3) Tranquillon vol-
canics and Monterey basal limestone ; (4) Matilija sandstone ; (5) sand-
stones of other formations; (6) Monterey cherty shale; and (7) clay
shales. In general, springs are most abundant in these formations where
the geologic structure is complex and where there is much landsliding.
One of several hot springs which issue from the Santa Ynez fault
occurs within the mapped area just south of Las Cruces. This spring is
apparently of deep-seated origin along the fault. The water has a tem-
perature of about 100° F., and carries some sulfur.
Few springs occur in the Purisima and San Rafael foothills.
Ground Water. A detailed investigation of the ground-water
resources of Santa Ynez and Lompoe Valleys has recently been completed
by J. E. Upson and others.^^ In Lompoe Plain and throughout the flood-
plain of the Santa Ynez River, wells drilled into the basal gravel member
of the alluvium produce water in large amounts sufficient for irrigation.
The Careaga sand which underlies this gravel in Lompoe Plain is likewise
M^ater-bearing, but the loose sand runs into the wells and causes trouble.
Irrigation water is also produced from wells drilled into alluvial gravels
of stream valleys traversing the San Rafael foothills and upper Santa
Ynez Valley. Alluvial sands and gravels of Los Alamos Valley also yield
large amounts of water.
The alluvium of stream valleys within the Santa Ynez Mountains
and Purisima Hills generally contains too much loam and too little gravel
to produce enough water for irrigation, but generally yields enough for
stock or domestic purposes.
Wells drilled into gravels of the Paso Robles formation yield small
amounts of water. The Careaga sand yields fair amounts, but generally
causes sanding trouble. Diatomite, shale, and siltstone formations do not
yield water unless fractured. Brittle, fractured Monterey cherty shale
•" Trask, Parker D., and others, Geologic description of the manganese deposits of
California: California Div. Mines Bull. 125, p. 173, 1943.
«5 0p. cit,1947.
1950] LITERATURE CITED 83
will generally yield water — sometimes in fair quantities. Sandstone gen-
erally yields small amounts, but when the formation is tight, the water
comes mainly from fractures or joints rather than from the sandstone
itself. Under favorable structural and topographic conditions fair
amounts of water can be obtained from sandstones. J. S. HoUister has
drilled several near-horizontal wells into steeply dipping Matilija sand-
stone on the Hollister and San Julian ranches and has obtained up to 120
gallons per minute of excellent water.
Water from some formations locallj' contains large amounts of
mineral salts. This is especially true of waters from serpentine, or from
the Sespe, Vaqueros, and Monterey formations, which locally contain
hj'drogen sulfide, sulfate, and carbonates of calcium, magnesium, iron,
sodium, and potassium,
LITERATURE CITED
Antisell, Thomas, Geological report : Pacific Railroad Survey, vol. 7, pt. 2, chap.
10, pp. 65-74, Washington, D. C, 1856.
Arnold, R., and Anderson, R., Geology and oil I'esources of Santa Maria oil
district, Santa Barbara County, California : U. S. Geol. Survey Bull. 322, pp. 1-161,
1907.
Bailey, T. L., Origin and migration of oil into Sespe red beds, California : Am.
Assoc. Petroleum Geologists Bull., vol. 31, no. 11, pp. 1913-1935, 1947.
Bramlette, M. N., Monterey formation of California and origin of its siliceous
rocks : U. S. Geol. Survey Prof. Paper 212, pp. 1-55, 1946.
Clark, B. L., and Yokes, H. E., Summary of marine Eocene sequence of western
North America : Geol. Soc. America Bull., vol. 47, no. 6, pp. 851-878, 1936.
Dibblee, T. W. Jr., Lompoc oil field : California Div. Mines Bull. 118, pp. 427-
429, 1943.
Dolman, S. G., Lompoc oil field, Santa Barbara County, California : California
Div. Oil and Gas, Summarv of Operations, California Oil Fields, Rept. 17, no. 4, pp.
13-19, 1932.
Dolman, S. G.. Capitan oil field : California Div. Oil and Gas, Summary of
Operations, California Oil Fields, Rept. 24, no. 2, pp. 15-26, 1938.
Efiinger, W. L., Gaviota formation of Santa Barbara County, California
(abstract) : Geol. Soc. America Proc. 1935, pp. 351-352, 1936.
Gill, J. P., Eocene algal sandstone (abstract) : Geol. Soc. America Proc. 1936,
p. 383, 1937.
Hill, Mason L., Classification of faults : Am. Assoc. Petroleum Geologists Bull.,
vol. 31, no. 9, pp. 1669-1673, 1947.
Keenan, M. F., The Eocene Sierra Blanca limestone at the type locality in
Santa Barbara County, California : San Diego Soc. Nat. Hist. Trans., vol. 7, no. 8,
pp. 53-84, 1932.
Kelley, F. R., Eocene stratigraphy in western Santa Ynez Mountains, Santa
Barbara County, California : Am. Assoc. Petroleum Geologists Bull., vol. 27, no. 1,
pp. 1-19, 1943.
Kribbs, G. R., Capitan oil field : California Div. Mines Bull. 118, pp. 374-376,
1943.
Loel, W., and Corey, W. L., The Vaqueros formation, lower Miocene of Cali-
fornia, I Paleontology: Univ. California Dept. Geol. Sci. Bull, vol. 22, pp. 31-410,
1932.
Mulryan, H., Geology, mining, and processing of diatomite at Lompoc, Santa
Barbara County, California : California Div. Mines Rept. 32, pp. 1.33-166, 1936.
Nelson, R. N., Geology of the hydrographic basin of the upper Santa Ynez River,
California : Univ. California Dept. Geol. Sci. Bull., vol. 15, no. 10, pp. 327-396, 1925.
Porter, W. W. II, Gaviota-Conception area: California Div. Mines Bull. 118,
pp. 372-373, 1943.
84 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Rpp(l, R. D., Geology of Cnlifoniin. .Sf);' pp., Tulsa, Oklahoma, Am. Assoc.
Petroleum (leolojii.sts, 19oo.
Reed, R. D., and Hollister. J. S., Structural evolution of southern California,
157 pp., Tulsa, Oklahoma, Am. As.soc. I'etroleum Geologists, 1936.
Regan, L. J. Jr., and Hughes, A. W., Fractured reservoirs of the Santa Maria
district, California : Am. Assoc. Petroleum Geologists Bull., vol. 33, no. 1, pp. 32-51,
1949.
Schenck, H. G., and Kleinpell, R. I\I., The Refugian stage of the Pacific Coast
Tertiary: Am. Assoc. Petroleum Geologists Bull., vol. 20, no. 2, pp. 215-225, 1936.
Taliaferro, N. L., The relation of volcanism to diatomaceous and associated
siliceous sediments : Univ. California Dept. Geol. Sci. Bull., vol. 23, no 1. pp 1-56,
1933.
Trask, Parker D., and others, (ieologic description of the manganese deposits of
California : California Div. Mines Bull. 125, p. 173, 194;{.
Upson, J. E., Late Pleistocene and Recent changes of sea level along the coast
of Santa Barhara County, California : Am. Jour. Sci. vol. 247, no. 2, pp. 94-115, 1949.
Upson, J. E., Thomasson, H. G. Jr., and others. Geology and water resources
of Santa Ynez river valley, Santa Barbara County, California : U. S. Geol. Survey
Duplicatetl Rept., pp. 1-322, June 1947.
Woodring, W. P., Upper Eocene orbitoid foraminifera from the western Santa
Ynez Range, California, and their stratigraphie significance: San Diego Soc. Nat.
Hist. Trans., vol. 6, no. 4, pp. 14.5-170, 1930.
Woodring, W. P., Bramlette, M. N., Lohman, K. E., and Bryson, R. P., Geologic
map of Santa Maria district, Sant^i Barbara County, California : U. S. Geol. Survey
Oil and Gas Investigations, Prelim. Map 14 (in six sheets), 1944.
Woodring, W. P., Bramlette, M. N., and Lohman, K. E., Stratigraphy and pale-
ontology of the Santa Maria district. California : Am. Assoc. Petroleum Geologists
Bull., vol. 27, no. 10, pp. 1335-1360, 1943.
Woodring, W. P., Loofbourow, J. S. Jr., and Bramlette, M. N., Geology of Santa
Rosa Hills, eastern Purisima Hills district, Santa Barbara County, California : U. S.
Geol. Survey Oil and Gas Investigations, Prelim. Map 26, 1945.
INDEX
A
Agua Caliente Canyon region : Alegria formation in, 30 ; faulting in, 55
Alegria Canyon region : Alegria formation in, 30 ; Monterey sediments, tar-soaked,
pi. 17 ; Monterey shale in, pi. ISB, pi. 14, pi. 15A ; Santa Ynez fault in, 55 ;
terrace deposits in, 50 ; Vaqueros formation in, 32
Alegria formation, 29, 30-31, 32, pi. IIB, 38, 49, 62, 68 ; marine facies of Sespe forma-
tion, 30-31
Algae, calcareous, from Monterey limestone, 40, 80
Alisal Canyon : Espada formation in, 22 ; Rincon claystone in, 33
Alisal Canyon region, Vaqueros formation in, 32
Alisal gravel quarry, 81
Alisal-Nojoqui area : see Nojoqui- Alisal area
Alisal ranch region, faulting in, 57
Alluvium, Recent, 38, 39, 48, 50-51
Amoles Creek region: Tranquillon volcanics (?) in, 34; see also Los Amoles region
Anita shale, 23, 24, 25, 26, 27, pi. lOJ^, 38, 49, 01, 62; Sierra Blanca limestone lens
in, 25
Anticlinal structures : see Structure, 51-60
Arroyo Hondo region : Alegria formation in, 31 ; Gaviota formation in, 31 ; Vaqueros
formation in, 32
Artesian water : see Springs
Asphalt, 75; tar-soaked sediments, Monterey, pi. 17; tar-soaked sediments, Sisquoc,
43,44
Astrodapsis antiselli zone, 48
Astrodapsis hreweriantis zone, 48
Astrodapsis peltoides zone, 48
"Aucella" crassicollis zone, 49
''Aucella" piochii zone, 49
B
Baculites chicoensis zone, 49
Baggina californica zone, 42
Ball & Son, N.W., 81
Basement : see Franciscan
Bentonite, 80; in Monterey shale, 40 ; in Tranquillon volcanics, 34, 36, 38
Birbent Canyon, Sisquoc formation in, 44, 46
Birbent Canyon region : Careaga formation in, 45, 46 ; structure, 60
Bixby Canyon, Tranquillon volcanics in, 34
Bixby Canyon region, Vaqueros formation in, 31
Boliviiia h iighesi zone, 42
Briones moUuscan stage, 48
Buell Flat gravel quarry, 81
Buell Flat Rock Company, 81
Buellton region, pi. \2B ; unconformity in, pi. 12A
Bulito Canyon : Alegria formation in, 31 ; see also El Bulito Canyon
Bulito Canyon region : faulting in, 56 ; Gaviota formation in, 29
Bulito fault, 56
Burton Mesa : Franciscan formation in, 21, 62 ; Lospe formation in, 33 ; Monterey
shale in, 37; petroleum exploration in, 67; physiography, 19; Sisquoc formation
in, 43, 64 ; structure, 51, 58, 65
Burton Mesa region, Orcutt formation in, 50
C
Cabrillo, exploration of Santa Barbara coast by, 9
California Division of Highways, 81
Callejon gravel quarry, 81
Canada de la Vina region, Monterey shale in, 35
Canada de Santa Anita : Gaviota formation type locality, 29 ; petroleum exploration
at mouth of, 68 ; see also Santa Anita Canyon
Canada de Santa Anita region, Alegria formation type locality, 30
Caiiada del Capitan region : Vaqueros formation in, 32 ; see also Capitan Canyon
(85)
86 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Canada del Rodeo region, Tranquillon volcanics in, 33
Canada FA Jolloru region : faulting in, 57 ; see also Jolloru Canyon region
Canada El Morida region, faulting in, 57
Canada Honda : Anita shale in, 26 ; Canada Honda fault in, 56 ; Espada formation
type locality, 22 ; faulting in, 56, 57 ; Honda formation type locality, 22
Canada Honda fault, 56
Canada Honda region, Tranquillon volcanics in, 34
"Capay" molluscan stage, 49
Capitan Beach, Tranquillon volcanics at, 34
Capitan Canyon: Alegria formation in, 30; Sespe formation in, 30; see also Caiiada
del Capitan
Capitan Canyon region : faulting in. 57 ; Sesi>e formation in, 31
Capitan oil field, 67-68; Erburu fault in, 57, 67 ; structural map of, 66
Capitan-Point Conception area, petroleum from, 67
Capitan region. Las Yeguas fault in, 58
Careaga formation, 39, 43, 44, 45-46, 47, 48, 58, 59, 60, 65; asphalt in, 75 ; ground water
from, 82
Careaga station region, Careaga formation type locality, 45
Cascadian revolution, 65
Casmalia Hills : Espada formation in, 23 ; Lospe formation in, 33 ; Orcutt formation
type section in, 50
Casmalia oil field, Lospe formation in, 33
Cebada Canyon : Careaga formation in, 46 ; faulting in, 59
Cebada member, Careaga formation, 46
Celite, 75, 77
Cephalopoda, from Jalama formation, 24
Chico formation, correlation with Jalama formation, 24
"Chico" molluscan stage, 49
"Cierbo" molluscan stage, 48
Coast Range orogeny, 65
Coast Ranges, diastrophism, 61
Cojo Canyon region : Alegria- Vaqueros contact in, 31, 32 ; bentonite in, 80 ; Monterey
shale section in, 36
Cojo fault, 56
"Coldwater" sandstone, 24, 67, 68 ; see also Sacate formation
"Coldwater" zone, Capitan oil field, 68
Collophane, in Monterey shale, 41
Corral Canyon, Erburu fault in, 57, 58
Corral Canyon region, Sespe formation in, 31
Covarrubias zone, Capitan oil field, 67
Cox & Chilson, 81
Cozy Dell shale, 24, 26, 27-28, pi. IIA, pi. 12B, 38, 49, 62; repetition along Bulito
fault, 56
Crassatella collina reef, in Gaviota formation, 29
Cretaceous, 38, 39, 49, 51, 53, 54, 55. 56, 60, 61; Anita shale, 26; Espada formation,
22-23; Jalama formation, 23-24
Cretaceous and Eocene beds, unconformity between, pi. 12A
Cretaceous rocks : Matilija sandstone unconformable on, 27 ; Sisquoc formation uncon-
formable on, 44
Cross, R. K., 9
Cuarta Canyon, view west along coast from, pi. 16A
Cuarta Canyon region : Alegria-Sespe gradational contact in, 30 ; Monterey shale in, 36
Cuyama River, Obispo tuff at mouth of, 34
D
de Anza, Juan Bautista, 10
de la Guerra, Francisca, 12
de la Guerra, Jose Antonio, 11, 12, 13
de la Guerra, Maria Antonia, 11
de la Guerra, Pablo, 11
Deformation : see Geologic history, 60-65
Delmontian stage, 34, 36, 37, 42, 44, 48, 63, 64
Dendraster reef, Careaga formation, 46
Desmoceras colusaensis zone, 49
1950]
INDEX 87
Diatomite, 75-79; gioimd water from, 82 ; in Monterey shale, 37, 41, 42, 43 ; in Sisquoc
formation, 37, 38, 39, 41, 43-44, 64
Diatoms : from Foxen formation, 45 ; from Monterey shale, 36, 40, 42 ; from Sisquoc
formation, 44
Dibblee. Albert, 12
Dibblee, T. W., 9, 12
Dibblee, Thos. Bloodgood, 12, 13
Dibblee, W. C. H.. 78, 80
Dibblee gravel quarry. 80-81
Dicalite Company, 78. 79
Dicalite diatomite quarries, 78-79
"Domengine" molluscan stage, 49
Drainage, southwestern Santa Barbara County, 19
Drake area, petroleum exploration in, 68
Drum Canyon : gravel quarry at mouth of, 81 ; Sisquoc formation in, 43
Dune sand : in Careaga formation, 46 ; Recent, 39
E
Echinarachniiis gabbii zone, 48
Echinoidea, from Careaga formation, 47
El Bulito Canyon, pi. 10-B ; see also Bulito Canyon
El Chorro ranch, gravel quarry on, 81
El Jaro Canyon : Espada formation in, 22 ; gravel quarries in, 80, 81 ; limestone in,
40. 79, SO ; Tranquillon volcanics in, 34
Eocene, 38. 49, 54, 55, 56, 61 -62, 80 ; Anita shale, 24. 25, 26; Cozy Dell shale, 24, 27-28;
Matilija sandstone, 24, 25, 26-27; Sacata formation, 24, 28-29; Sierra Blanca
limestone, 25-26
Eocene and Cretaceous beds, unconformity between, pi. 12JL
Eocene formations, petroleum from, 67, 68
Eocene-Oligocene series, 24-30
Eocene zone, Capitan oil field, 67, 68
Erburu fault, 57-58, 67
Erburu zones, Capitan oil field, 67
Erosion cycles, southwestern Santa Barbara County, 19-20
Espada Canyon, diatomite in, 77
Espada formation. 22-23, 25, 33, 37, 38, 39, 49, 54, 61, 69; faulted against Gaviota
formation. 57 ; faulted against Rincon shale, 57
"Etchegoin" molluscan stage, 48
F
Faulting : see Structure
Fernando formation, equivalent of Careaga formation, 45
Ferrelo, exploration of Santa Barbara coast. 9
Figueroa Canyon region, San Marcos anticline in, 60
Fish remains, in Sisquoc diatomite, 64
Fish scales, from Monterey shale, 42
Flagstone, 80
Foraminifera : from Anita shale, 26 ; from Cozy Dell shale, 28 ; from Foxen formation,
45 ; from Gaviota formation. 29 : from ]\Ionterey shale. 34. 36. 40. 42 : from
Rincon shale, 33, 34 ; from Sacate formation, 29 ; from Sierra Blanca limestone,
25-26 ; from Sisquoc formation, 44
Foraminiferal stages, 48-49
Formations, in southwestern Santa Barbara County, age of, 48-49
Fossils: Actinocyclina aster, 26; Amnurellina, 28; Atnaurellina aff. moragai. 27;
Amaurellina inezatia, 26; Aucella. 22; "Aucella'' crassicoUis, 23; "AucelW^
piochii, 23; Baculites, 23, 24; Calva steinyi, 23, 24; "Cardium hreicerii," 29;
Crassnfella colUna, 29; Cj/praea, 28; DenHraster axhieyi. 46, 47; DiscocycJina
psila. 26 ; Drillia graciosana, 47 ; Ectinochilus canalifer supraplicatiis. 27 ; Ficop-
sh hornii, 27; Ficopsis ret)iondii. 27; Ficus gesieri, 29; Ficus maniillatus. 27
Galeodea, 25: Galeodea susanae, 27; Gari hornii, 27; GlycyiJieris veatchii, 24
Gypsina, 26; Inoceramus, 24; Lucina cf. annulafa. 47; Macot)ia nasiita, 32
Macoma cf. nafiuta, 47; "Macrocallixta'' conradiana. 26; Macrocallista hornii
27; ifactra ashburnerii. 24; Nassa moraniann, 47: Xemocardium linteum. 27
Xummulites, 26; Olequahia cf. hornii, 27; OliveUa bipUcata, 47; Operculina
26; Ostrea eldridgei, 32; Ostrea idriaensi^, 25, 28; Ostrea tayloriana, 29, 31
88 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Fossils — (Continued)
Pecten maguolia, pi. 13A ; "Pecten peckhami," 42; Pecten (Amusium) lonipo-
censis. 34 ; Pecten (Chlamyx) sespeenuLi, .32 ; Pecten (Chhimya) yneziana, 29, 31 ;
Pecten (Lyropccten) cenosensi.s, 47; Pecten (Lyroperten) cxireUanun, 34; Pecten
(Lyroperten ) vuuinoUa, 32, 34 ; Pecten (Patinopectcn) liealeyi, 47 ; Pecten (Pec-
ten J vanrlecki, 32 ; Pitar uvusaniis, 27 ; Pseudocurdiuni cf. densatutn, 47 ; Rapana
raqiierosensis, ,32; Schedocardia cf. hreirerii, 27; (Seraphs enntica, 27; Sipho-
generina cnlloiiii. .3(5 ; Siphonalia inerrianii. 21) ; Tivela inczmia, 29, .31 ; Trachycar-
diiiin raiiiicroKcnsi.-i. 32; Triyonitt, 23. 24; Triyonia erniisi. 24; Trigonia giboni-
ana, 24; Trochitu radian.s, 47; Tinrilclln (ippluKie, 27; TurritcUa inezana, 32,
1)1. 1.3.1 ,■ TurrJteUa inezanu var. altdcorona, 32; Turritelhi gonostoma hemphilli,
47; Turritella ocoyuna, 34; Turritelhi scrippsensi.s, 27; Turritella temhlorensis,
34 ; Turritella urnsnna, 25, 27 ; Turritella varinta, 29, 31 ; Turritella variata var.
Juliana. 2N ; Valrulineria californica, 36 ; Venericardia hornii, 29 ; Venericardia cf.
hornii. 2S ; "Venerupsis" cf. haunihali, 47; Volutaderma cf. gahhi. 24; YoWia cf.
cooperii, 47.
Foxen Canyon, Sisquoc fauna from, 44
Foxen Canyon region, Siscjtioc formation type locality, 4.3
Foxen formation, 39, 43, 44-45, 46, 48, 64 "
Franciscan debris : in Jalama conglomerate, 23 ; in Lospe conglomerate, .33 ; in Paso
Robles formation, 47 ; in Sespe conglomerate and red beds, 62 ; in Vaqueros con-
glomerate, 32, 62
Franciscan formation, 21-22, 33, 3.J, 37, .38, 39, 40, 49, 51, 53, 58, 60-61, 62, 63, 69;
Honda shale member, 22 ; manganese in, 81 ; Matilija sandstone unconformable
on, 27 ; Monterey shale unconformable on, 60 ; Sisquoc formation unconformable
on, 44 ; source of Poppin shale iron oxides, 26 ; springs issuing from, 82
"Franciscan" molluscan stage, 49
Fremont, John C, 11
G
Galeodea susanue zone, 49
Gas, natural : see Petroleum, 67-74
Gastropoda: from Gaviota formation, 29; from Careaga formation, 47; from Jalama
formation. 24 ; from IMatilija sandstone, 27 ; from Sacate formation, 28 ; from
Vaqueros formation, 32
Gato Canyon region, Monterey shale in, 36, 37
Gaviota, view northeast from, pi. 117?
Gaviota Beach region : asphalt in, 75 ; Monterey conglomerate in, 40 ; Sisquoc forma-
tion in, 43, 64
Gaviota Canyon region : x4_legria-Sespe gradational contact in. .30 ; bentonite in, 80 ;
Eocene-Oligocene series in, 24 ; Gaviota formation in, 29 ; Monterey shale in, 37 ;
^Monterey shale section in, 36 ; Sisquoc formation in, 37 ; Vaqueros formation
in, .32
Gaviota formation, 24, 25, 28. 29-30, 31, pi. 117?. 38, 49, €2, 68 ; faulted against Espada
formation, 57 ; faulting in, 57 ; petroleum from, 67, 68
Gaviota Gorge, 53
'"Gaviota" molluscan stage, 49
Gaviota Pass region, Santa Ynez fault in, 54, 55
Gaviota region : Monterey-Sisquoc disconformity in, .35 ; terrace deposits in, 50
Gaviotito fault, 56; Cretaceous-Tertiary section uplifted along, 53
Geographic features, southwestern Santa Barbara County, 14-15
Geologic history, southwestern Santa Barbara County, 60-65
Geomorphology, .southwestern Santa Barbara County, 17-20
Gibraltar Dam region, faulting in, 54
Gijote Canyon, bentonite in, 80
Government Point, petroleum exploration at, 68
Government Point region, Cojo fault in, 56
(Jraciosa member, Careaga formation, 46
Gravel, road : see Road gravel
Great Lakes Carl)on Corporation, Dicalite Division, 78, 79
Ground water, 82-83
H
Harris region, Foxen formation type locality, 45
History, southwe.stern Santa Barbara Couutv, 9-13
Holli-ster, J. S., 83
Hollister, James J., 12
1950] INDEX 89
Hollister, W. W., 12
Hollister ranch, ground water on. 83
Honda formation, 22, 38, 49, 60-61
Honda School, faulting near. 57
Horsetown formation, type, correlated Avith Kspada formation, 23
"Horsetown" molluscan stage, 49
Hot springs : see Springs, 82
Hughes. A. W., 9
J
"Jacalitos" molluscan stage, 48
Jalama (Canyon) anticline. 53. 56
Jalama Canyon, pi. lOJ. ; Anita shale in. 26 ; Jalama formation in, 23, 24 ; Matilija
sandstone in, 27 ; Monterey diatomite in. 37 ; Monterey shale in, pi. 157? ; Poppin
shale in. 26 ; Rincon claystone in. 33 ; Sierra Blanca limestone in. 25, 26 ; Si.squoc
formation in. 43
Jalama Canyon region, faulting in, 55
Jalama Creek, Vaqueros couglomei-ate near, pi. 13.4
Jalama formation, 23-24, 25, 26, pi. 10.1, pi. lOB, pi. 12.1. pi. 12B, 38, 49, 56, 61 ;
faulted against Rincon shale, .54
Jalama syncline, pi. 10.1
Johns-Man\ ille diatomite quarries, 77-78
Johns-Mauville Products Corporation, diatomite producers. 75. 77, 78
Jolloru Canyon region : Tranquillon volcanics in, 34 ; see also Caiiada El Jolloru
Jonata Park region : asphalt in. 75 : diatomite in. 77
.Juncal formation, correlation with .\nita shale. 24
Jurassic. 38, 39. 49. 55, 56, 59-61; Espada formation. 22-23; Franciscan formation,
21-22; Honda formation, 22
K
Knoxville formation. 39 ; type, correlated with Espada formation, 23 ; type, correlated
with Honda formation. 22
"Knoxville" molluscan stage, 49
L
La Purisima Concepcion, Mission, 10
La Salle Canyon, diatomite quarry in. 79
La Salle Canyon region, limestone in, 79
Laramide orogeny, 61
Las Cruces : Crassatella coUina reef near. 29 : hot spring near. 82
Las Cruces region : Gaviota formation in, 29 ; gravel quarry in, 81 ; Matilija sandstone
in. 27 ; sulfur spring in, 55
Las Yeguas Canyon, faulting in, 58
Las Yeguas fault. 58
Lasuen, Padre, 10
Limestone. 79-80 ; in Monterey group, 40, 63, 80, 81 ; in Paso Robles formation, 47
Limestone quarries. 34. 79-80
Little Pine fault. 60 ; Sisquoc formation exposed on. 44
Llanitos Canyon, bentonite in, 80
Lompoc anticline, 58. 59
Lompoc diatomite quarries, 37, 43, 78, 79
Lompoc lowland. 51. 53. 58
Lompoc oil field. 68-69; asphalt deposit at. 75; Franciscan formation in. 21; Lospe
formation in. 33 ; Monterey shale in. 42 ; structure, 58, -59
Lompoc Plain : alluvium in. 50. 51 : ground water in. 82
Lompoc region : Careaga formation in. 45 ; limestone in. 79. 80
LomiX)c Valley: diatomite deposits south of. 75. 76-77; ground water in, 82; history,
13; Monterey shale in. 37; petroleum exploration in, 67; physiography. 18-19;
structure, 51. 58
Lompoc Valley region. Orcutt formation in, 50, 65
Lompocan orogeny, 63, 65
Los Alamos limestone, in Paso Robles formation, 47
Los Alamos region, Los Alamos syncline in, 59
Los Alamos .syncline. 51, 53, 59, 65 ; Sisquoc formation in, 44, 64
Los Alamos trough : Foxen formation in, 64 ; Monterey sediments in, 63
90 SOUTHWESTERN SANTA BARBARA COUNTY [BuU. 150
Los Alamos Valley : alluvium in, 51 ; Carcajia formation in, 45 ; Foxen formation in,
45 ; ground water in, 82 ; Monterey shale in, 37 ; Orcutt formation in, 65 ; Paso
Robles formation in, 47, 60; structure, 59-60; traversed by Los Alamos syn-
cline, 51
Los Amoles Canyon, gravel quarry in, 81
Los Amoles Canyon region : flagstone from. 80 ; see also Amoles Creek region
Los Olivos region, Los Alamos syncline in, 59
Los Sauces Creek, Sierra Blanca limestone in, 25
Lospe formation, 33, 37, 39, 62
Luisian stage, 36, 41, 42, 48, 63
M
Manganese ore, 81 -82
"Marker diatomite," in Sisquoc formation, 43
"Martinez" molluscan stage, 49
Matilija Canyon: Cozy Dell shale type locality, 24; faulting at, 54; Matilija sand-
stone type locality, 24
Matilija sandstone, 24, 25, 26-27, 28, pi. lOA, pi. IIA, pi. 12A, 38, 49, 62; ground water
from, 83 ; repetition along Bulito fault, 56 ; springs issuing from, 82
Mattel's Tavern, 13
"Meganos" molluscan stage, 49
Mineral resources, southwestern Santa Barbara County, 67-83
Mineral waters, 83
Miocene, pi. 10.4, 38, 39, 48, 55, 56, 57, 62-64, 75, 76, 80; Lospe formation, 33; Mon-
terey shale, 34-42; Rincon shale, 33; Sespe formation, 31; Sisquoc formation,
43-44; Tranquillon volcanics, 34; Vaqueros formation, 31-32
Miocene formations, folding, 53
Missions, southwestern Santa Barbara County, 10
Modelo formation, correlation with Monterey shale, 34
Mohnian stage, 35, 36, 41, 42, 48, 63
Mollusca : from Alegria formation, 31 ; from Careaga formation, 46, 47 ; from Eocene
at Wons Canyon, 25 ; from Gaviota foi'mation, 29 ; fi'om Matilija sandstone, 27 ;
from Monterey shale, 42 ; from Sierra Blanca limestone, 26 ; from Sisquoc forma-
tion, 44 ; from Tranquillon volcanics, 34 ; from Vaqueros formation, 32
Molluscan stages, 48-49
Molluscan zones, 48-49
Monterey sediments, tar-soaked, pi. 17
Monterey shale, 25, pi. ISB, 33, 34-42, pi. 14, pi. 15.4, pi. 15B, pi. 16.4, 43. 44, 45, 48,
54, 55, 56, 58, 59, 60, 63, 65, 68, 69 ; asphalt in. 75 ; bentonite in, 40, 80 ; Careaga
formation unconformable on, 46 ; collophane in, 41 ; diatomite in, .37, 41, 42, 43,
75-79; faulted against Rincon shale, 58; faulted against Sisquoc formation, 56;
flagstone from, 80 ; Franciscan formation unconformably overlain by, 60 ; gravel
quarries in, 81 ; ground water from, 82-83 ; limestone in, 40, 63, 79, 80, 81 ; mineral
water from, 83 ; organic content, 42 ; petroleum in, 42, 63, 67, 69 ; silica in, 40,
41, 63 ; springs issuing from, 82
Monterey shale debris:. in Careaga formation, 46; in Orcutt formation, 50; in Paso
Robles formation, 47 ; in Sisquoc formation, 44, 64
"Moreno" molluscan stage, 49
N
Natland, M. L., 9
Natural gas : see Petroleum, 67-74
"Neroly" molluscan stage, 48
Nevadan orogeny, 61
Nojoqui-Alisal area : faulting in, 52, 57; Sespe formation in, 62 ; spring in, 82; uncon-
formity at base of Sespe in, 32
Nojoqui Canyon, pi. 12i? ; Espada formation in, 22, 23 ; Jalama formation in, 23 ;
Rincon claystone in, 33 ; Sierra Blanca limestone in, 25, 80
Nojoqui Canyon region : unconformity in, pi. 12A ; Vaqueros formation in, 32
O
Obispo tuff, 33, 34, 40
Oil : see Petroleum, 67-74
Oligocene, 38, 49, 55, 62; Alegria formation, 30-31; Gaviota formation, 24, 29-30;
Sespe formation, 31
Oligocene formations, petroleum from, 68
1950] INDEX 91
Orcutt formation, 39, 48, 50, 58, 65
Orciitt oil field, Lospe formation in, 33
Orcutt region, Orcutt formation type section in, 50
Orefia, Caspar, 12
Orogenies : see Geologic history, 60-65
Oyster reefs, in Alegria formation, 30
P
Pacifico, The, 55, 56 ; see also Santa Anita Canyon
Pacifico anticline, 53, 55, 56
Pacifico fault, 23. 54, 55-56; Cretaceous-Tertiary section uplifted along, 53
Paleogeography : see Geologic history, 60-65
Paleontology : see Fossils
Panoche formation, correlation with Jalama formation, 24
"Panoche" moUuscan stage, 49
Paskenta formation, type, correlated with Espada formation, 23
"Paskenta" raoUuscan stage, 4!)
Paso Robles formation, 39, pi. 16B, 45, 46, 47, 48, 50, 51, 58, 60, 65; ground water
from, 82
Pecten coaJingaensis zone, 48
Pelecypoda : from Careaga formation, 46, 47 ; from Gaviota formation. 29 ; from
Jalama formation, 24 ; from Matilija sandstone, 27 ; from Monterey shale, 42 ;
from Sacate formation, 28 ; from Yaqueros formation, 32
Petroleum, 67-74; in Monterey shale, 42, 63; see also Capitan oil field, Casmalia oil
field, Lompoc oil field, Santa Maria Valley oil field, Zaca oil field
Petroleum, wells drilled for, 34, 60, 67, 70-74; Frank Buttram Xo. "Reuben" 1 well,
59 ; General Petroleum Corporation Nos. "Erburu" 1 & 8 wells, 67 ; National
Exploration Company well, 59 ; Richfield Oil Corporation No. "Skytt" 1 well,
69 ; Rothschild Oil Company No. "Orella" 1 well, 68 ; Shell Oil Company No.
"Covarrubias" 1-35 well, 67; Shell OU Company No. "Covarrubias" 1-36 weU,
68 ; Shell Oil Company No. "Covarrubias" 1-37 well, 57 ; Shell Oil Company No.
"Rutherford" 1 well, 68; Standard Oil Company No. "Gerber" 1 well, 68;
Tidewater Associated Oil Company No. "Davis" 1 well, 69 ; Tidewater Asso-
ciated Oil Company No. "Leonis" 1 well, 34 ; Union Oil Company No. "Purisima"
19 well, 59 ; AVestern Gulf Oil Company No. "Hollister" 1 well, 68 ; Whittier
Associates Nos. "Barham" 1, 2, & 3 wells, 69 ; Wilshire Oil Company No.
"Hollister" 1 well, pi. 16A
Phosphatic material : in Foxeu formation, 45 ; in Monterey shale, 41, 42 ; in Sisquoc
formation, 44, 76
Physiography, southwestern Santa Barbara County, 17-19
"Pico" moUuscan stages, 48
Pleistocene, 38, 39, 48, 51, 65; Orcutt formation, 50; Paso Robles formation, 47, 50;
terrace deposits, 50
Pleistocene orogeny, 58, 65
Pliocene, 38, 39, 48, 64-65, 75; Careaga formation, 45-46; Foxen formation, 44-45;
Paso Robles formation, 47, 50; Sisquoc formation, 43-44
Poett, A. Dibblee. 80
Point Arguello region, Honda shale in, 60
Point Conception region: Alegria formation in, 30; petroleum in, 67, 68; Sisquoc
formation in, 43
Point Pederuales, Tranquillon volcanics at, 34
Point Pcdernales region : Espada formation in, 22 ; faulting in. 56 ; Honda shale in, 22
Point Sal formation, 33, 34
Poppin shale, 26
Portola, Caspar de, exploration in Santa Barbara region, 9-10
Psilomelane, 81
Purisima anticline, 58, 59, 69, 82
Purisima anticline, western, 59
Purisima Canyon : asphalt in, 75 ; Careaga formation in, 46 ; faulting in, 59
Purisima Hills : alluvium in canyons of, 51 ; asphalt in, 75 ; Careaga formation in,
45, 46, 64; diatomite in, 75. 77; Foxen formation in. 44. 45; Franciscan forma-
tion in, 62 ; ground water in, 82 ; Monterey shale in, 37, 64 ; Paso Robles forma-
tion in, 47 ; petroleum in, 67 ; petroleum exploration in, 67, 69; Sisquoc formation
in, 43. 64 ; physiography, 18; springs in, 82 ; structure 51, 59, 65
Pyrolusite, 81
<i
I-
92 SOUTHWESTERN SANTA BARBARA COUNTY [Bull. 150
Q
Quaternary system, 48, 51
Quiota Canyon : offset by faulting, 55 ; Rincon claystone in, 33 ; Tranquillon vol-
canics in, 34 ||
Quiota Canyon region : Santa Yiiez fault in, 54 ; Sespe formation in, 31 |i|
R
Radiolaria, from Monterey shale, 42 ^
Rafaelan orogeny, 63-64
Ramajal Canyon : Sierra Blanca limestone in, 2() ; A'acpieros formation in, pi. 13.4
Rancho San Julian : see San Julian ranch
Ranchos, southwestern Santa Rarhara County, 10-13
Recent, 38, 39, 48 ; alluvium, 50-51 ; subsidence during, 51
Recent stream gravels, quarry in, 81
Redrock Mountain, asphalt in, 75
Refugian fauna, from Las Cruces region, 28
Refugian stage, 29, 31, 49, 62
Refugio Canyon : anticline in Monterey shale, 68 ; Refugio fault in, 57
Refugio Cove area, petroleum exploration in, 68
Refugio fault, 57
Refugio gas field, 68
Refugio Pass, Matilija sandstone in, 27
Relizian stage, 33, 34, 35, 36, 40, 42, 48, 63
"Repetto" molluscan stage, 48
Rhythmic bedding, in Monterey shale, 42
Richfield Oil Corpoi-ation, 9
Rincon shale, 31, .32, 33, 34, 35, 36, 38, 48. .54, 57, 62, 63, 68 ; faulted against Espada
formation, 57 ; faulted against Jalama formation, 54 ; faulted against Monterey
shale, 58
Road gravel, 80-81
Rothwell, W. T., 9
Russel, C. E., 9
S
Sacate Canyon : Sacate formation type locality, 28 ; Sisquoc formation in, 36
Sacate formation, 24, 25, 27, 28-29, 30, pi. IIA, 38, 49, 62, 68; flagstone from, 80;
petroleum from, 67, 68
Salsipuedes Canyon : Anita shale in, 26 ; Espada formation in, 22, 23 ; Jalama forma-
tion in, 23
Salsipuedes Canyon region, diatomite in, 37, 77
Salsipuedes Creek region : Sisquoc formation in, 43 ; structure, 78
San Joaquin formation, correlated with Careaga, 47
"San Joaquin" molluscan stage, 48
San Julian Canyon, Rincon claystone in, 33
San Julian ranch, 9, 11-13; Orassatella, collina reef near, 29; diatomite deposits on
78 ; flagstone quarry on, 80 ; ground water on, 83 ; gravel quarry on, 80, 81 ;
Sespe overlapped by Vaqueros on, 31
San Julian Valley : Rincon claystone in, 33 ; Vaqueros formation in, 32
San Julian Valley region, flagstone from, 80
San Lucas Canyon: Espada formation in, 22, 23, 61; faulting at, 54, 55; Monterey
shale in, 37 ; serpentine in, 22, 61
San Lucas region, structure, 54
San Luis Obispo County, Obispo tuff in, 33
San Marcos anticline, 60
San Marcos Pass region : Eocene in, 24 ; Gaviota formation in, 29
San Miguel Canyon region, structure, 78
San Miguelito Canyon region, diatomite in, 37, 77
San Onofre Canyon, faulting of Gaviota sandstone in, 57
San Pascual Canyon : Honda formation in, 22 ; Monterey shale in, 35 ; serpentine in, 22
San Pascual Canyon region, limestone in, 79
"San Pedro" molluscan stage, 48
San Rafael foothills : alluvium in canyons of, 51 ; Careaga formation in, 45, 46 ; Foxen
formation in, 45 ; ground water in, 82 ; Paso Robles formation in, 47, 60 ; petro-
leum in, 67 ; physiography, 18; removal of Monterey shale in, 40 ; Sisquoc forma-
tion in, 44, 46 ; Sisquoc-Monterey relationship in, 37, 63 ; springs in, 82 ; struc-
ture, 60, 65
1950] INDEX 93
San Rafael Mountains : deformation. 61 : Espada formation in. 23 ; Franciscan forma-
tion in. 21; manganese in. SI; pb.vsiographr, 17-18; Rafaelan orogeny in. 63;
serpentine in, 22 ; Sierra Blanca limestone type locality, 25 ; source of Paso
Robles formation. 65 ; spruigs in. S2 : structure. 60; uplifted bv faulting. 51
San Rafael uplift. 51. 61, 62. 63, 64
Santa Anita Canyon : Anita sbale type locality. 26 ; Jalama formation in. 23. 24 ;
Poppin shale in. 26 ; Sespe formation in. 30 ; see also Cafiada de Santa Anita,
The Pacific-o
Santa Anita Creek, course along Pacifico fault. 55
Santa Aque<la Canyon, geology in wells at, 60
Santa Barbara. Mission. 10
Santa Barbara County Road Department, SO, 81
Santa Barbara embayment, 61. 62
Santa Barbara-Goleta region. Sespe basal ojnglomerate in. 31
Santa Barbara-Ventura Basin region, petroleum in. 67-68
Santa lues. Mission. 10. 13. 82
"Santa Margarita" shale. 43
Santa Maria Basin: Careaga formation in, 45; deformation. 61; diatomite in. 75;
Los Alamos sync-line in, 51 ; Lospe formation in. 33 : Monterey shale in. 35. 37;
Paso Robles formation in. 47. 65: petroleum in. 67. 68-69; Point Sal formation
in. 34 : structure. 59 ; submergence during Plioc-ene, 46, 65
Santa Maria Basin, southern, stratigraphic column. 39
Santa Maria Valley : Careaga formation in. 45 ; Foxen formation in, 45
Santa Maria Valley oil field, effect of Rafaelan orogeny on. 63
Santa Rita fault. 56-57
Santa Rita Hills : Careaga formation in. 45. 46 : diatomite in. 76 ; faulting in. 56 ;
petroleum exploration in, 67 ; Sisquoc formation in, 43 : Sisquoc-Monterey dis-
conformity in. 35. 64 : structure, 53
Santa Rita Hills region. TranquUIon volcanics in, 34. 63
Santa Rita A" alley : Orcutt formation in. 50 ; part of Lompoc lowland structural
province. 51. 58 ; Paso Robles formation in, 47, 50 ; structure, 58
Santa Rosa anticline. 57
Santa Rosa Hills : Jalama formation in. 24 : Matilija formation in. 27 : Monterey
shale in. 35 : Rincon elaystone in, 33 ; Sac-ate formation in, 28 ; Sespe formation
in. 31 ; structure. 53
Santa Rosa HUls region, faulting in. 57
Santa Rosa Park, gravel quarry near. 81
Santa Rosa Ridge. Anita shale in. 26
Santa Ynez fault. 54-55; hot springs along. 82; Santa Ynez Range uplifted along.
51. 53, 54
Santa Ynez fault, north branch. Cretaceous-Tertiary section uplifted along, 53
Santa Ynez fault system. 54-56, 57
Santa Ynez Mountain uplift. 51
Santa Ynez Mountains, pi. lOB. IIA : alluvium in canyons of, 51 : Anita shale in. 26 ;
bentonite in. SO ; Cozy Dell shale in. 27 : diatomite in. 75. 76-77; Espada forma-
tion in. 22. 23 : flagstone rock in. 80 : Franciscan ( ? i formation in. 21 : Gaviota
formation in. 29 ; Gaviota-Vaqueros contact in. 32 : geologic history. 61. 62. 63.
64. 65 ; ground water in. 82 ; Honda shale in. 22 ; Jalama formation in. 23 : lime-
stone in. 79 ; Matilija sandstone in. 26: Monterey shale in. 35-37, 42; Oligocene
faulting. 62; petroleum exploration in. 67; physiography. 17; removal of Mon-
terey shale in. 40 : Rincon daystoue in. 33 ; Sacate formation in. 28 ; seri)entine
in. 22 ; Sespe formation in. 31 : Sierra Blanca limestone in. 25. 80 ; source of
Paso Robles formation. 65; springs in. 82; structure, 53-58; Tranquillon vol-
c-anics in. 34 ; Vaqueros formation in. 31. 32
Santa Ynez Mountains, western, stratigraphic c-olumn, 38
Santa Ynez-Pacifico fault zone. 53
Santa Ynez Range, pi. lOA. 55 : Alegria formation in. 30 : Anita shale in. 26 : Cozy
Dell shale in. 27 ; Cretac-eous and Eocene in. 61 ; Eocene-Oligocene series in,
24-25 ; Gaviota formation type area. 29 : Jalama formation in. 23 ; Matilija
sandstone in. 27 ; Monterey shale in. 35. 36. 37 : Sespe formation in. 31 ; Sisquoc
formation in. 43 ; uplifted along Santa Ynez fault. 51. 54 ; Vaqueros formation
in. 32
Santa Ynez region : Careaga formation in. 45. 46 : diatomite in. 77 ; Fernando forma-
tion in, 45 ; folding in, 59
?
I
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