GEOLMY f Physical 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 ^ 5 , ly*' • . ; 4' ULUkVMXI J_L l£0 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 V L 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. ''i i% /■ ,* -"* 1^ 1^ ^ «;■. 'J o ^ --J \9 4/ r 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 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 [BuU. 150 CO 15 O »-( H o « o o < Pi PS o o O o a CO PS Ph Ph w pi « H O PS w o l-l 1 w OS H H O o ij l-H PS o u l-H PS o PS c < > CO w o <: H 2 .g o (D a o <; 'a O § P .2 o Q c 'S O B .2 '3 PS .2 IP 3 m 2 o E u n 1° '3 "o Kl - : o "b o - E M . : o It' c3 - a- e o M % g s l-l - CO AMVI >4d3 iivno AU VIJ L)I3 1 1 ^ I 1950] STRATIGRAPHY 49 > ) H Pl, CO W CO O W o > o Q N o o < ANITA & SIERRA BLANCA •> d < < ■ p CO < p o o m o fa 'a 0) a; 'oj d 13 13 o o o ■-I (N CO << < "tn O d 03 o "o d 2 fa 1: e s e e 1 1 e c i s e s c CO o 1 O c c Co s Eh o o o .CO 00 O u •iSl GO e 05 00 e 1 00 g CO .09 O s O p. S P3 t3 H 1-1 Q 1— I o Ph l-J Q P l-H e5 w o 1^ Oh t3 'ono 3N3D03 > ^t l\ fll' d31 sno 33Via ,« DISS ivMnr s 3 o U JH c 4> «. (A o Q. o c O c ■*" o. — — o o u JE > u w c ^ 9) O TJ O 3 CO E o Q> U O o- w o w O 9> •*- « o 2 o o C 3 O 1 O — ,o u o a v> c « c a> < o > o JZ ^ c o o a> c 3 ■a *~ w ^ o •o w c Q. E o E c o O ^ o W f u c •^ C 3 - $ u o. u a> o o o u f o. a> > x: c o ••- (A «- 0> c o 3 (A Qi 'B O o •"-I o I C be a 3 ni 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 a e e J. e •♦* s e 00 S o B !^ O a. o .* ^ e s Oh a I ■sa . o <1> o _o "o o ■-S 1-5 l-J >-5 1-^ W M MM =8 ;-H t*H C^ O CO CO. °8 .-^ iT. CD OO lUOiZl o. o. o, o. a. o o o o o o o" o M a o" o T-< O »0 OO O O (M OO CO I^ ^H CO O 1— < CO CO o — ' ^ ^ OT e« =^"2 '-3 ?^^^£ >> a c u o jq >> >, cS « CO ^ a o oO aOO m 0530^ "11 r (U "^^ T-H 6 2; t;: a ■n 3T3 H CQ rt rt (M rt •z •z -z •T3 3 CO •T3 3 CO -a 3 CO a o O 0° ■ w w a ca o. O O O 03 -o, „ a 60 bo-g > m> o ( s e e o o a. o 1 O I o ,^ J " O O J 1 •o 'CO ■^ ^ l'""' ^- '•S o TO !-^ > H '^"" o C5 , . !ka cc I I hi ^ i i . >> _^--^ ^•* .-^ . M — — i= 'e— O r^ ^g = — ~; fr- e- p- ^- ff— e— fr- £ C aS ^ac 3C __£ _^S _ao ^SD ^, 4i ^r ' _,,^ _ • " cSat, -' " J " = 2 -H -H ::r, o c; = c: = ' ceo P5— < — «o CCCSJ =.0, S O i ''r — r CC T TT r^-T'T .raor ■^ — t^ — Jl c: c: =i c= =: — =i -— Cfl — — C>-^0 — t^b*t^t^ — e« a: oooo < <<< <<<< << <:<::^<:<<<;<<<<<<<:::<-<<<> <:!;<<<:<<<<<:<<<<<: o o •^ « o s -^ rr ■<»" 6 -1 | — s = szzzzzz. ■<— feffc. 5 = 5 = 3^11 = — z — "? ^ "^ 5."^ ^s !^ !s !e !£ !s ' -•< z =_' o z c^^ — I ZZ ■ a 51: :ZZZ = : : : : 5^ j<)_. aa.ajaMaaasaaa a a a i i ,.^ a .»! s* a o S e e s 00 i-H S§ 1^ CO a as CO 00 S CQ CO.. . Q< P« P< O O O E-iHH -H a a .. o o- -*J -*J o o s.^"00CCiCD'^CDCS l>-M'OeQO°OOC'"5"^»^Ot^OOOSQOOOt>- »-H if3 CD (M o C^ '"' "^ "^ "^ O »-< . O -^ t^ O CO (M -^ CO •^ CO 1-* CO Tf W3 05 O oco CD O ^ Tt' IC CO CO lO O OO »0 *-« CO -^ OS CO CO Ol UD O CO CO f— ' ■^ C^ CO '^^ CO ooo -*• ■t-H C^ OS QO CDt^ rt( rr »0 1° •^ CD j "^ rt^ »CCDkCiOOCSCD(MOlOlCOOUOiOic22'^ •rt< O "rr* C<» O O 04 CO T- . c^ O "^ -^ "^ — OSOSOSOiOSOSOJOiOSOSDSCTSOSOi rvQ,' ^.o5 iC OS OS *r ■^ CO CO Tf OS OS OS OS O OS ■^ CO OS OS W5 W3 o »o r— (M ^ZmZ2;p:i ^ " 3 c3 O-S 3 3 3 'Z^z,' ZilzS''-'. ^ ^ ^ ^ ^ ^ cq-. ^-H O — — < ° 6 6 6 §§Z;2;ZZ ««=2aa a a cj :3 03 itj rt oopHmpam 3 a 3 ° ■= ^ o nj rt o 62; 2;_g s~ ^ a ta C3 C3 H c^*-' coco oct;666o oo- ca S^ 3 3 3 tj ■ga o. O o o 2" I il\ac£.M ca -tJ ja c a ta o ca o ca-^^>- 5^ o o <; ^ rt rt m is rt H M c o o oOO -^ — — . goo 2 c a ■o 2 2 >> c e WPP O o ■as O O CJ o c^ U — O O O O O O 3 ra U3 tn c/3 en V] O CO V} CO CO 03 CQ 03 t« u (ri ti I-. t-> "TJ a> a> Qj -<' O M O ►-< O a ■= -S CO o o_' 00 = — _-ja ."3.-, CJ OO 3 ■3-a ca I-. L- r. ca P3" -o-a §§^ OTOTiJoe-'E-HH HHEh ^ c^ rt ClJ ^ if & & * OJ OJ qj <« s s OJ (K 0^ T3T3T3 S^ »-HC> o o & o o .*^ .k^ ..A .t^ *^ .^ .^ 03 S3 :3 rf 33 :9 ci S 5 S S 5 S S © o o c; o i; o r2 r3 ."H ^ ^ r2 "2 H H H £-■ H H H o -a ca 0000000 O Co a e s o> o o a o 8 o >. * ■a >, >. t, 5S CS 5-3 -0 C^ I. -. «J " S a-^a "2^ 3 ^ Mo bO *** *j 2 .-J 09 • s»- ■ — t*- J* 3 rr ^ "353 " " 25,000,00 0,000.000 shows bel 9,000.000 -3-3 M-a 3 u u be u -i-i-8^ o_ (iioi «i M H i ;^: ^■H ^■s c «:: 1,0, ai £r >• CS >• S >• > H HE- Hr-f-e-H • - » 1 ca 1 =5 : ! 1 : ; W!^ ■ ^ ;h : ; I ; : S\ ; '.. ;°3 : ; 1 ! ! ^ C3 .^ ' OQ ' ' ' ' ' ^c-, ; t-. IH ; ! ! ; ; Tv(? idiff. a 10 loo 1 1 1 i"^ lOO 1 1 1 tt> ;§;;;;§ - 3 ; ^ '.>::::'? 10 H n'* ooe-j 1 ^ Ivl 1 ! 1 iH ■3 Cs Ci ' »0 Tr(?) to 49 & shale Tv 171 " I. ■ ICO •« op Tm 150'± Ta 1110'; 111 Tea sandstone op Tr 850'±; 34004- Tr 2800' Tim 500' 00' 'IV 3094 Tv 3371 Tv 3 120 Till 800' §•§"§•§■§& E- H HH Hr-f-H ^ ^ ^ ^ N oso c; 1^ ooc li^ c. ca OC c^ ic c; »^ — CO OS OS QO =;: iO c^izsoizD Q TT ■n"0 CO CO CO -r CO CO 0, • i i ; ; i ; !"§ II 1 1 1 1 F-*? S c — ' CO 03 C3S 05Q0O 0^ CO CO CO CO C^ C^ CO CO ^r fe** Ci C3 OS OS OS OS OS OS cs 1° ^ j6^ ^■^ JJ=^XJ < << << <;<<< S 1 1 1 ^ ^ d d ' « —1 e«' — ' «' «' z z — do 6 6 6 6 i §° zz zzzz -.3 -JZ (. b^ t« b. t^ L^ D. C.^ isS -gSSS K S " .2 S 2 S .2 2 0^ c c ^ C) CO 0000 00 KS s=:ss Ui J c^ i dc3 ' ' i 3 u ^ : 0- i^ : Id s ons. ;. Pc ICo xpl. IfOi If Oi Go. Co.. t. Ci Universal C Doheny-Pac Standard Oi Monterey E Wcsteru Gu Western Gu WiJshire Oil Gaviota Oil Republic I'e &d ^ CS CO rr u^ OI>.OOOS S^ Q oa QQ QQQQ 6 — 13966 74 SOUTflWESTERN SANTA BARBARA COUNTY [Bull. 150 %8 o« Co e e 23 p ra -a s go l§ .2 "^ O ttl ;i 2 oS^; o O Hi o o >, « SB Mfc^' o >oo >o'" o . ova o O o c^ tn Q Q O ]00 H O ooo o o ui .o O0(M>.*'''— 'O— tlO I-- .-* CO O O CO CO ^3-- "^ r^ — , •— • CD ic lO >^ >>!->;>>> Q.'^ p, A Q. O. Q. C Qt o"ooooooo CC O ■— ' to GC CO O -— ' Tf GO -+■ CO lO t^ >>>>> p. p. c Q. D, a. o o o o o o I H .-o H H ^ O C^ M T > O O > P. CU Q. OOO H Eh ^ ■Tfi O lO CO CO CO CO OI>- lOCO -^ CO CO C^ GO CO '— ' Cq r-.C^ r-H CD l>- Oi CO t>* O CO C33 CO CO CD GO lO OS -—t OO CO »>• OO CD I>. »— ( ^ OCO"^ CO -^ T— • (N *-( CO -^ 1— I '* CO ^ -s ro ra (I C3 t- PhChOOOOO ooo I tC CQ |_ rt rt QJ O 33 6 6 632-az; OOcccocortrtO&q o 2 3 3 .D CO C^ ^rj< 6 6 6. CO CO w c5 1-1 fcH tj O U4 1-. (_ ^ > !> > S o o o-§ - fe a H-?*; 300 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