STATE OF CALIFORNIA EARL WARREN, Governor DEPARTMENT OF NATURAL RESOURCES WARREN T. HANNUM. Director DIVISION OF MINES FERRY BUILDING, SAN FRANCISCO 11 OLAF P. JENKINS, Chief SAN FRANCISCO SPECIAL REPORT 18 MARCH 1952 GEOLOGY OF THE WHITTIER-LA HABRA AREA LOS ANGELES COUNTY, CALIFORNIA By CHARLES J. KUNDERT Digitized by the Internet Archive in 2012 with funding from University of California, Davis Libraries http://archive.org/details/geologyofwhittie18kund GEOLOGY OF THE WHITTIER-LA HABRA AREA, LOS ANGELES COUNTY, CALIFORNIA By Charles J. Kundert • OUTLINE OF REPORT Page Abstract 3 Introduction 3 Stratigraphy . r » I'pper Miocene Puente formation "> Lower Pliocene Repetto formation 7 I'pper Pliocene Pico formation 10 Alluvium 11 Pleistocene La Habrn formation 11 Structure 11 Faults 11 Folds 12 Subsurface structure 12 Age of faulting and folding 12 Paleontology 13 Environment suggested by the fauna 13 Petrology 13 Deposition of the Repetto formation 10 fJeomorphology 10 Economic geology 20 Illustrations Page Plate 1. Geologic map of Whittier-La Habra region In pocket 2. Geologic sections across Whittier-La Habra area In pocket 3. Map of the Whittier oil field In pocket Figure 1. Map of Los Angeles region showing location of Whit- tier-La Habra area 4 2. Stratigraphic table of formations south of Whittier fault ^ 3. Photo of lower Puente siltstone 7 4. Photo of upper Puente sandstone and siltstone 8 5. Photo of diatomite beds in upper Puente fault block 8 fi. Photo of Hoover conglomerate 7. Photo of Central Fee member 10 8. Photo of small normal fault in Lost Conglomerate 10 0. Sketch cross-section through Lost Conglomerate 11 10. Photo of oyster bed in upper Pliocene rocks 12 11. Photo of angular unconformity between La Habra formation and upper Pliocene siltstone 12 12. Photo of unconformity in La Habra formation 13 13. Photo of La Habra formation 13 14. Photo showing fault contact between upper and lower Puente beds 17 15. Photo showing eastern exposure of recumbent fold 17 16. Photo showing western exposure of recumbent fold 10 17. Photo showing "X" fold in upper Puente beds 20 18. Sketch diagram, explanation for position of Repetto formation north of Whittier fault 20 10. Graph showing production of Whittier oil field 21 ABSTRACT The Whittier-La Habra area is about 15 miles east of the City of Los Angeles, and lies along the southern flank of the northwestern Puente Hills. The mapped area is a strip about miles long and 1 J to 2 miles wide. •Junior Mining Geologist, California Division of Mines. Condensa- tion of a thesis presented to the Claremont Graduate School in partial fulfillment of the requirements for the degree Master of Arts. Manuscript submitted for publication December 1951. The principal structural feature of the area is the Whittier fault, a high-angle reverse fault that has the north side thrust over the south side with about 7,000 feet of apparent vertical displacement. A right- lateral horizontal movement is suggested by geomorphic and struc- tural evidence. North of the Whittier fault is a restricted belt of block faulting and intense folding; south of the Whittier fault the rocks form a less disturbed south-dipping homocline. Stratigraphic units exposed in the area are: (1) upper Miocene Puente formation of four members — lower Puente siltstone, middle Puente sandstone, upper Puente siltstone. and Sycamore Canyon sandstone and conglomerate; (2) lower Pliocene Repetto formation composed of siltstone, sandstone, and conglomerate beds; (3) upper Pliocene Pico siltstone; (4) tipper (?) Pleistocene non-marine La Habra formation of unconsolidated gravel, sand, and silt; and (5) Quaternary alluvium. Some of the interbedded conglomerate beds in the Repetto forma- tion have numerous sedimentary clasts which cannot have been trans- ported any appreciable distance in ordinary media. These beds are surrounded by siltstone containing deep-water microfossils. A pos- tulated means of deposition of these "deep water" conglomerate strata is by slump-initiated turbidity currents. Early Pliocene move- ment along the Whittier fault is suggested as the trigger for the slumps. Sandstone in all parts of the mapped area is arkosic containing a high percentage of feldspar that suggests granitic source rocks. Pebble counts throughout the mapped area also show a high per- centage of granite and similar rock types. The central San Gabriel Mountains is suggested as a major ultimate source area for the sediments. INTRODUCTION The area studied lies along the southern flank of the northwestern Puente Hills (Whittier Hills) near the City of Whittier, 15 miles east of the City of Los Angeles. The area extends from the month of Turnhull Canyon south- east to Fullerton Road. Field work was started in the fall of 1949 and completed in the spring of 1951. The mapping was done on aerial photographs on the scale of 660 feet to the inch. Previous Work. The early discovery of oil in the Pu- ente Hills led to considerable geologic work. Eldridge and Arnold 1 named the Puente formation and divided it into three units. In their discussion of oil fields they described the stratigraphy and structure of the Whittier oil field. The Whittier Hills, according to English, 2 are "the part of the Puente Hills directly north of the City of Whittier and east to La Habra Canyon." All the area south of the Whittier fault was mapped as 1 he Fernando group, a name used for all beds of Pliocene age. Krneger :1 removed 11800 feet of alternating beds of conglomerate, sandstone, and siltstone from the Fernando, and called it the Sycamore Canyon formation. The microfaunal contents were iden- tified as upper Miocene. Ilolmaii, 4 in 194)5, described the geologv of the Whittier oil field. Daviess and Woodford 5 1 Eldridge, G. H. and Arnold, Kalph, The Santa Clara, Los Angeles, and Puente Hills oil fields : U. S. Geol. Survey Bull. 309, 1907. 2 English, W. A., Geologv and oil resources of the Puente Hills region, southern California: U. S. Geol. Survey Bull. 768, 192G. 3 Krueger, M. L., The Sycamore Canyon formation, California (ab- stract) ; Am. Assoc. Petroleum Geologists Bull., vol. 20, p. 1520, 1036. ' Hnlman, W. H., Whittier oil field: California Div. Mines Bull. 118, pp. 288-291, 1941!. Daviess, S. X. and Woodford, A. O., Geology of the northwestern Puente Hills, California: I'. S. Geol. Survey oil and gas investi- gations, Prelim. Map 8:i, 1949. (3) Special Report 18 N S LOS s a n g e if e s "';:;,;••■"'/ 10 20 MILES Figure 1. Map of the Los Angeles region showing location of the Whittier-La Habra area. Wiiittier-La Habra Area recently published a thorough study of the geology north of the "Whittier fault, with geologic map and structure sections. Acknowledgments. Professors A. O. Woodford and J. S. Shelton furnished guidance and advice during the study. M. L. Natland of the Richfield Oil Corporation generously identified the microfossils. Mason L. Hill of Richfield Oil Corporation, and 8. N. Daviess of the Gulf Oil Company inspected the field work and discussed the stratigraphic and structural problems. Standard Oil Com- pany of California generously permitted publication of well log data. Pomona College rendered financial aid with a Bracken scholarship. STRATIGRAPHY Upper Miocene Puente Formation Following the precedent established by Daviess and Woodford, four members of the Puente formation are recognized in the Whittier Hills. They are: lower silt- stone, middle sandstone, upper siltstone, and Sycamore Canydii — totaling 8500 feet or more in thickness. South of the Whittier fault the Hoover conglomerate and Cen- tral Fee sandstone crop out. These units may be equivalent to the uppermost units of the Sycamore Canyon member. Lower Puente Siltstorn Member. The lower siltstone member of the Puente formation is exposed north of the Whittier fault at the extreme northwestern edge and the extreme northeastern margin of the mapped area. The exposure north of the Whittier fault in the vicinity of Turnbull Canyon is illustrated in section B-B' (pi. 2). The principal outcrops are laminated siltstone and platy porcelaneous shale. A few impure limy lenses are ex- posed along Turnbull Canyon road. The rocks dip to the north and are right side up as indicated by graded bed- ding. Immediately north of the Whittier fault, along Turnbull Canyon road, is a small anticline, shown In- graded bedding to be overturned. Foraminifera found in these road cuts were stunted forms of Bolivina of Mio- cene age. The siltstone fault block in the northeastern part of the area west of Fullerton road, is poorly exposed because of a citrus and avocado cover. The rocks are typically porcelaneous shale and laminated siltstone. although limy siltstone and sandstone lenses from 10 to 50 feet in length abound in the road cuts. The rocks are dipping to the south and are in fault contact with the rocks to the north and south. No fossils were found. Middle J'ik nti Sandstone M< mber. The middle Puente member east of Hacienda Boulevard has been divided into two parts : an upper sandstone unit, and a lower silt- stone-sandstone unit. The lower, finer unit is exposed north of the Whittier fault near the Hacienda Country Club. The principal lithologic types are thin-bedded sandy siltstone and sand- stone with a thin limy conglomerate bed near the base. The lower contact is the Whittier fault. The upper con- tact is placed at a lithologic change from fine- to coarse- grained sediments. Approximately 1100 feet is assigned to this unit. The upper, coarser unit includes about 250 feet of medium- to coarse-grained, brown, massive sandstone. •Daviess, S. N. and Woodford, A. O., Geology of the northwestern Puente Hills, California : U. S. Oeol. Survey, Oil and Gas Investi- gations, Preliminary Map 83, 1949. The contact of this unit and the overlying upper Puente siltstone member is obscured by a citrus cover. A thick series of sandstone, siltstone, and conglomerate beds west of Hacienda Boulevard is mapped tentatively as middle Puente. Daviess and Woodford ' found lower Mohnian (lower and middle Puente) foraminifera at the eastern edge of this series. It is suggested that the series west of Hacienda Boule- vard is middle Puente and that it represents a facies change of the eastern section with coarsening to the west, The distinction in the lithology of the two eastern units disappears in the west as the amount of coarser material increases. A fault of unknown displacement as shown on the ma]> accentuates the difference between the series east and the series west of Hacienda. The top of the western section is the base of a medium- grained brown sandstone approximately 50 feet thick marking a change in lithology to the thinly bedded upper Puente sandstone and siltstones of the overlying beds. I pper Piienti Siltstorn Member. Although the best section of upper Puente iii this area lies in the center of the mapped area north of the Whittier fault, it is in- complete because of complications arising from faulting and folding. Woodford et al. 8 have measured 2500 feet of upper Puente rocks. The base of the upper part of the Puente formation is the base of the brown sandstone bed that served to mark the top of the middle Puente units. Overlying it is a series of thin-bedded siltstone and sandstone layers, containing three main intercalated diatomite beds and other smaller ones in the upper part of the section. Associated with the diatomite arc siliceous shale and siltstone beds. Of the three main beds of diatomite which ranee in thickness from .'{ to ."> feet, the lowest bed is the thickest and purest. Above these beds are more intercalated sandstone and siltstone. The section above the sandstone, making the "S" fold in section E-B' (pi. 2) consists of an alternating series of thinly bedded diatomite, sandy siltstone and. near the top, some siliceous shale beds and an associated thin tuff bed. West (if the "S" fold is a small elbow-shaped conglom- erate lentil, containing large angular blocks of sedi- mentary material together with crystalline pebbles and cobbles. The conglomerate, which is intercalated with the surrounding sandy siltstone and overlying siliceous shale, is unsorted and forms a discordant pod in the sediments. Daviess 8 interpreted it as a small submarine slum]) dur- ing the time of deposition. The nearest conglomerate lies 1000 feet stratigraphically above the slumped material. Overlying the siliceous shale are more thinly bedded sandstone and sandy siltstone units, including one promi- nent sandstone bed near the top of the section. The top of the upper part of the Puente formation here is the base of the conglomerate forming the south limb of the large overturned syncline. Foraminifera of upper Moh- nian age were found in two places (table 1. F 25, F 26) in the section. A fault block of upper Puente siltstone consisting of diatomite and siltstone beds is exposed north of the Whit- ' Daviess, S, \\, and Woodford, A. O., op. cit. • Woodford, A. O., Moran, T. <:.. and Shelton, J. S.. Miocene con- glomerates of Puente and San Jose Hills, California: Am. Assoc. Petroleum i feologists Bull., vol. 30, pp. 51 !-.">i'>0, 1946. Personal communication. Special Report 18 Figure 2. Stratigraphic chart of formations south of the Whittier fault. Age Geologic formation Description Approximate maximum thickness (in feet) V u •> Alluvium Gray gravels, sands, and silts; unconsolidated, poorly sorted, exposed in canyon floors. ? « e t> u o ■ E La Habra Non-marine conglomerates, 'gravels, sands, and silts; poorly consolidated, in places crossbedded. 1500 (?) 4) a Ml Pico siltstone — unconformity — Gray to tan sandy siltstones and silty sandstones; some conglomerate and limy layers. 5000 B O o s a w u s s o h3 Upper Repetto Middle Repetto Lower Repetto Tan to gray sandstone with interbedded conglomerates. Increasingly sandier toward the base; becoming finer to the east. Gray to dark gray sandy siltstone, usually massive, becoming sandy to the west; Lost conglomerate, interbedded sandstone and conglomerate at the base. Tan to gray sandstones, siltstones, and thin conglomerates. Siltstones weather to a distinctive gray-blue. More conglomerates and sandstones appear to the west. 1100 1100 1600 V a c u o V c o u o si • a. o. D Hoover conglomerate Central Fee sandstone Strongly bedded, well indurated, cobble-pebble conglomerate with a dark red matrix, thinner and sandier to the east. Interbedded sandstones and siltstones having sharp contacts; very high content of wood fragments throughout the formation. 750 1050 tier oil field. The principal diatomite bed exposed is about 4 feet thick and is associated with two obscure subordi- nate beds about 2 feet thick. A small outlier of rocks of upper Puente age in sand- stone of middle Puente age is preserved in a small syn- cline east of Hacienda Boulevard. An upper Mohnian fauna (table 1, F 37) was collected from the outlier. Another fault block west of Fullerton road exposes upper Puente beds. The section here consists of siltstone, sandstone, and one conglomerate bed which has 50 percent sedimentary cobbles and pebbles of impure limestone and siliceous shale, probably derived from the lower Puente siltstone. The upper Puente rocks in the mapped area are in- competent units, in many places highly contorted into tight folds, many of which are too small to map. Because creep and landsliding are prevalent, faults are traced with difficulty. Sycamore Canyon Member, Puente Formation. Krue- ger 10 measured 3800 feet of sandstone and conglomerate in the type area west of Turnbull Canyon. Daviess and "Woodford n mapped some 3000 feet of section that they called Sycamore Canyon. No estimate can be made as to 10 Krueger, M. L., The Sycamore Canyon formation, California (ab- stract) : Am. Assoc. Petroleum Geologists Bull., vol. 20, p. 1520, 1936. 11 Daviess, S. X. and Woodford, A. O., op. cit. total thickness in the Whittier area, because there is no continuous section. Two areas of Sycamore Canyon rocks are found north of the Whittier fault : the section of the overturned syn- cline in the mapped area, and a fault block in the western half of the area. The south limb of the overturned syncline lies conform- ably on the upper Puente. Four thin conglomerate beds coalesce to form the thickened south limb and the bulk of hill 944. The conglomerate is composed of pebbles, cobbles, and a few boulders in an earthy red matrix, and forms a resistant outcrop along its entire exposure. The north, or overturned limb, is less red and is subdivided into two conglomerate beds of which the northern is the more persistent. Overlying the conglomerate beds is a series of sandy siltstone and fine sandstone beds typically half an inch to 2 inches in thickness. The rocks of the fault block shown in section B-B' (plate 2) are perhaps intermediate in position in the Sycamore Canyon member. At the Whittier fault contact, a crumpled black siltstone containing hard, brown sand- stone lenses prevails. Overlying the black siltstone is a series of thin-bedded medium- and fine-grained sand- stones, mostly tan to gray, in turn overlain by one con- glomerate bed and sandstone and sandy siltstone zones which extend to the northern fault boundary. No fossils were found in these sediments. Whittier-La Habra Area Pioi re 3. Lower Puente siltstone exposed along Turnbull Canyon Road. The beds are dipping to the north. Pebble-counts from tbe Sycamore Canyon conglomer- ate beds show lithologic types similar to those indicated in the upper Miocene pebble counts made by Olmsted. 12 Dacite porphyry is regrouped as a volcanic rock thus slightly changing Olmsted's rock type percentages. Pin- Vol- Meta- Sedimen- l'n- Olmsted (19.10) tonic canic morphic ttiry known (Average of eight) 4o.2 29.3 25.5 This report (Average of three P7, P., Pio) --_ 41.3 34 S.7 7 15.3 Except for the discrepancy in the metamorphic rock percentages (see table 3), there is close agreement in the results. The Central Fee unit, probably representing an upper unit of the Sycamore Canyon member, is a series of sand- stone and sandy siltstone beds south of the Whittier fault at the western margin of the mapped area. A rock ranging from sandy siltstone to silty sandstone prevails near the fault contact. Above this is a thick-bedded brown to yel- low-brown medium-grained sandstone about (j() feet thick. The rock in outcrop is poorly cemented, probably by ferruginous cement. A limy lens in this sandstone yielded foraminifera (table 1, F36) that Natland 13 said are prob- ably Miocene rather than Pliocene in age. Overlying the brown sandstone is fine-grained tan sandstone grading into sandy siltstone. Next in succession are sharply denned alternating beds of fine- to medium-grained sandstone, and sandy siltstone, ascertained to be right side up by graded bedding and minor channeling. The clastic series of the Central Fee unit has a high percentage of wood fragments. Total thickness of the Central Fee unit is approximately 1050 feet. Overlying the Central Fee sandstone is a thick, fairly competent cobble-pebble conglomerate bed containing some boulders and a few intercalated sandstone lenses in a red sandy or earthy matrix; it is excellently exposed behind the Lou Henry Hoover school in AVhittier, and can be traced along the strike to its truncation by the Whittier fault. A pebble-eounl made near the base of the conglomerate showed the following rock type percentages : Phi- Vol- Mrtn- Sedimen- l'n- tonic ciinir morphic toy known Locality PI 10 1> 18 12 12 Olmsted, F. H., Geology and oil prospects of western San Jose Hills, Los Angeles County, California : California Jour. Mines and Geology, vol. 4ti, p. 198, 1950. Pock types of the pebbles arc similar to those described by Olmsted. 14 and to the rock types of the Sycamore Can- yon conglomerates. This evidence, together with the re- sults of rough sand analyses made of samples taken throughout the mapped area suggest thai the Central Fee and Hoover units are .Miocene in age, as they differ greatly from the overlying Pliocene rocks, both in the mineral content of the sandstone and the rock types of the conglomerates pebbles. Further evidence for Miocene age of the two units is found in their appearance in outcrop. Typically. Syca- more Canyon conglomerate beds, like the Hoover beds, are well-indurated, ridge-forming, and have a relatively small percentage of interbedded sandstone. The overlying Pliocene conglomerates beds in contrast, are poorly cemented and generally contain 50 percent or more inter- calated sandstone units. The non-conglomeratic zones, also, of the Central Fee sandstone resemble the more tightly cemented, more clearly bedded rocks of the Mio- cene Sycamore Canyon member more closely than the weakly cemented, less clearly defined units of the over- lying Pliocene beds. Lower Pliocene Repetto Formation The Repetto formation at Whittier. containing approxi- mately 3,700 stratigraphic feel of sedimentary rock, in- cludes several coarse-grained members which rapidly become finer to the east. The bedding planes are commonly poorly defined, and the entire mass presents an uncon solidated appearance in comparison with the Sycamore Canyon member of the Puente formation. Natland '"' suggests a Whittier Narrows source for the coarse detritus in the Repetto formation. According to bis proposal tbe main channel of deposition during Re- petto time closely approximated the course of the present San Gabriel River. He postulates a coarse strip in the Repetto formation from the Whittier Narrows to Long Peach with thick deposits of finer material on either side. 13 Natland, Personal communication. "Olmsted, F. H., op. cit. ]i Oral communication. Special Report 18 Figure 4. Upper Puente sandstone and siltstone below the south linih of large overturned syncline showing well defined bedding planes. Beds are 2-3 inches thick. Wissler lG says that fairly thick coarse conglomerate beds are present in the lower part of the middle and the upper part of the lower Repetto formation at Montebello, which lies across the narrows from Whittier. The discovery of coarse deposits in the Repetto on both sides of the Whit- tier Narrows, coupled with a known rapid change to finer facies eastward, support Natland 's suggestion. Three stratigraphic divisions of the Repetto formation are recognized here : lower Repetto sandstone and silt- stone, middle Repetto siltstone, and upper Repetto sand- stone. These are in no sense faunal divisions comparable to those of Wissler. 17 Lower Repetto Sandstone and Siltstone. The lower part of the Repetto formation in the City of Whittier is a series of sandstone and conglomerate beds which become finer grained to the east. The maximum thickness at Whit- tier is 1600 feet. The top of the. Hoover conglomerate was selected as the base of the Repetto formation — a choice that is debatable and perhaps erroneous. However, since the placing of the contact is arbitrary, the writer selected a mappable horizon which remains reasonably consistent as far as the Whittier fault. In conformable contact with the Hoover conglomerate are dark gray, laminated, sandy siltstone beds that grade upward into fine-grained brown to buff sandstones con- taining large white micaceous flakes in many places. In- terbedded with the brown to buff sandstone is very white, fine-grained sandstone composed mainly of cpiartz grains. The entire sandstone series is very poorly cemented and permeable. Overlying the sandstone is a reddish-brown pebble-cob- ble conglomerate varying to a cobble-pebble conglomerate with numerous hard sandstone beds and a few soft silt- stone and sandstone beds. Above the conglomerate is a sandy siltstone and sand- stone unit, consisting of dark gray beds averaging- half an inch to an inch in thickness. A few rusty streaks and lenses of coarse material interrupt the sequence. Conform- ably overlying the sandy siltstone is a cobble-pebble con- 10 Wissler, S. G., Stratigraphic formations of the producing zones of the Los Angeles Basin oil fields: California Div. Mines Bull. 118, pp. 209-234, 1943. 17 Wissler, S. G., op. cit. glomerate, typically red-brown, with numerous sandstone lenses. The clasts are mostly subrounded and rarely attain boulder size. The conglomerate bed is overlain by a bed of tan to gray-white sandstone, overlain in turn by another red-brown conglomerate unit, more sandstone, and the arbitrarily fixed base of the middle Repetto siltstone. East of Whittier the lower part of the Repetto forma- tion becomes more fine-grained, and most of the conglom- erate lenses thin and disappear before they are cut off by the Whittier fault. The rocks in fault contact with the upper Miocene are sandy siltstone and fine-grained sand- stone which weather to a blue-gray color. These are over- lain by medium- and coarse-grained sandstone beds, some of which are very pure and white, but most of which are tan to dark brown. Thin conglomerate beds and well- cemented ridge-forming sandstone lenses are dispersed throughout the section. The section terminates at the base of the Lost conglomerate, a persistent marker bed, named for its disappearance due to faulting. The only foraminiferal locality found in the lower Repetto south of the fault (locality F 4, table 1) belongs to middle Repetto faunal zone described by Wissler. No megafossils were found. ^&&&&£ Figure .">. Diatomite beds in upper Puente fault block. Whittier fault is just out of view to left. Whittier-La Habra Area North of the Whittier fault is a long fault block mapped tentatively as the lower part of the Repetto formation ; it consists of siltstone and sandstone beds and one thick conglomerate unit. Lithologically the rocks resemble the Repetto sediments. Foraminifera from one locality, F 12, table 1, are not diagnostic. The fauna is probably Repetto in age, but may be upper Miocene. Middle Repetto Siltstone. The base of the middle Repetto series is mapped as the persistent cobble-pebble bed at the base of the Lost conglomerate which ranges in thickness from 30 to 300 feet. Few of the clasts reach boulder size, and most of them fall into the pebble class. However, at least 50 percent of the conglomerate as mapped is clean, non-pebbly, interbedded sandstone. Most of the clasts are subrounded, but some approach angu- larity, particularly the sedimentary clasts. Overlying the Lost ( longlomerate are gray-to-black sandy siltstone and silty sandstone beds most of them massive but more thinly bedded near the base. This mem- ber, also, coarsens to the west and loses its distinctive character and in Whittier, contains conglomerate and sandstone facies. Foraminifera were found in the siltstone at many lo- calities. The fauna ranged from the middle to upper Repetto faunal zones described by Wissler. Natland's Cassidulina lomitensis zone is well represented. Upper Repetto Sandstone. The basal bed of the upper Repetto sandstone is a red conglomerate, sandy conglom- erate, or, in places, a yellow-brown conglomeratic sand- stone. To the west the contact becomes obscure because of the intergrading of the coarse facies of the middle Re- petto series. Overlying the conglomerate arc gray to tan, medium- and fine-grained sandstone beds, usually from 6 to 24 inches thick. Thin conglomerate lenses are inter- calated in the sandstone. A ridge-forming, gray-white, well-indurated, cobble- pebble conglomerate in a matrix of coarse- and medium- grained sandstone with calcareous cement overlies the sandstone. The conglomerate averages 50 to 75 feet in thickness and forms an excellent marker zone along most of the contact. It is obscured to the west by talus and soil, and to the east by a facies change to finer material. The overlying rocks arc partly cemented, medium- to coarse-grained sandstone and granule sandstone beds, mostly red to yellow-brown, interbedded with pebble con- glomerate. The sediments occur in a succession of 10- to 15-feet thick beds; a small outcrop of the intercalated conglomerate has limy siltstone boulders 1 foot to 2 feet in diameter. Finer-grained deposits to the east bear foraminifera characteristic of the upper Repetto faunal zone, as defined by Wissler. Megafossil locality A 2 (table 2) is in a locally well cemented conglomerate, or conglomeratic sandstone. The conglomerate lias up to 90 percent sedimentary clasts, usually subangular to well rounded. Among the species represented from A 2 or two of note : Pecten (Lyropecten) estreallanus var. cerrosensis, and Pecten (Patinopcctcn) dilleri. Woodring and Bramlette 1s say that Lyropecten cerro- sensis is the last known Lyropecten proper to have lived in California seas. The genus, in the restricted sense, became 16 Woodring, W. P., and Bramlette, M. X., Geology and paleont<>l"Ky of the Santa Maria district, California : U. S. Geol. Survey Prof. Paper 222, 1950. Figure 6. Pari <>f the central portion of the Hoover .conglomerate behind Lou Henry Hoover School. The conglomerate is dipping steeply to the south. extinct about the end of the Pliocene epoch. They write of PatinopecU h dilleri, "The first left valve of P. dilleri to he illustrated was collected at a locality near Laguna Ojo de Liebre (Scammon Lagoon) in Lower California, 1,000 miles south of the type locality (the Eel River basin of northern California). /'. dilleri is found in intermediate strata of Pliocene age." 19 Woodring-'" says, "Lyropecten cerrosenses (locality 3007) and Oslnu vesper Una (locality 3009) occur in the Repetto formation." Pomona College has a collection from locality 3907 (Olinda Hill) containing many large well preserved specimens of Lyropecten cerrosensis and Pati- nopecten dilleri. Woodring- 1 places this fauna also in the group "Fossils of Intermediate and Shallow Water Fa- cies." although the foraminifera associated with them in the Whittier-La Habra area are a deep water fauna. The top of the Repetto formation is marked by a litho- logic change from coarse- to fine-grained sediments. East of section line E-E' (pi. 2) the top of a conglomerate bed lu Woodring, W. P., and Bramlette, M. N., op. cit. p. 94. 50 Woodring, W. P., Lower Pliocene mollusks and echinoids from the Los Angeles Basin, California : V. S. Geol. Survey Prof. Paper 190, p. 21, 1938. -' Woodring, W. P., op. cit. 10 Special Report 18 Figure 7. Sandstone and sandy siltstone of Central Fee member just below Hoover conglomerate. is mapped as the base of the upper Pliocene series. The average thickness of the exposed part of the conglomerate is 10 to 30 feet, although no complete section was found. The conglomerate has a limy matrix, essentially a marl composed of tiny shells and fragments of shells with silt. Casts of large pectens are abundant in the matrix as clasts. Large, well rounded boulders and cobbles of crystalline rocks are scattered throughout the matrix. Small angular fragments and one large 2-foot block of impure yellow- brown limestone and siliceous siltstone were found. Farther to the west a change from coarse sandy mate- rial to sandy siltstone marks the contact between lower and upper Pliocene rocks. Repetto Conglomerate Beds. A comparison of rock types in the Repetto conglomerate units with those of Olm- sted 22 follows : Meta- Redi- Pluionic Volcanic morphic menlary Unknown 64.0 10.5 25.5 Olmsted Five localities This report Eight localities 62.0 12.5 9.0 2.5 12.0 Upper Pliocene Pico Formation The base of the Pico formation is a marked stratigraphic boundary ; the Repetto formation is much coarser in gen- eral than the overlying upper Pliocene rocks. The observed contact lies 500 to 1000 feet farther to the east than sedi- ments containing foraminifera of Repetto age indicate. The lack of suitable marker beds of the Pico formation and poor exposures of the siltstone raise problems as to the nature of the upper Pliocene-lower Pliocene contact. Although no unconformity could be seen in the field, the widely varying strikes east of section E-E' suggest an unconformity. Moreover, some micropaleontologists be- lieve that only the upper part of the Pico formation is present in this area. The rocks of the Pico formation are principally tan to gray sandy siltstone and silty sandstone. The writer found very few true siltstone beds in the Pico. The strata are poorly bedded and in places massive in appearance. The lower half of the section exposed west of Hacienda Boule- vard has interbedded fine- to medium-grained sandstone and a few conglomerate beds. The upper half of the sec- tion in the same area has numerous limy lenses 2 to 3 feet in thickness, containing megafossils. The age determina- tion for the microfauna is upper Pico, except for some of the stratigraphically highest localities which have been called lower Pleistocene. The megafossil localities are less definite, but are considered to be of Pliocene age. The rocks east of Hacienda Boulevard are similar to those in the west. Scattered small conglomerate lenses occur ; most of the finer grained rocks are fine-grained sandstone and sandy siltstone. More megafossils are found in the eastern section than in the western section. Section line E-E' (pi. 2) passes through three patches of conglomerate considered to be contemporaneous. The arcuate patch lying south of the first turn in the section line is correlated with the two patches south of the second turn in the section line. The southernmost outcrop of conglomerate carries a lit- toral fauna, notably Tivela stultorum and Schizothaerus nuttalli. The conglomerate is very poorly cemented ex- cept for the basal 2 feet which are well indurated and form nick points in the ravines dissecting the outcrop. » Olmsted, F. H., op. cit, p. 202. Figure 8. Small normal fault in the western extension of the Lost Conglomerate. Sandstone is faulted against siltstone. Whittier-La IIabra Area 11 Covered N EXPLANATION Cobbles and boulders of metamorphic and igneous rocks Cobbles and boulders of sedimentary rocks Pebbles of metamorphic and igneous rocks Sandstone i 5 Feet , Elevation 550' Figure 9. Sketch cross-section through Lost Conglomerate member in an excavation near section C-C, plate 2. The fossils are found in a coarse-grained white sand about 10 feet thick, lying between two conglomerate members. Silty sandstone lies above and below the conglomerate beds. Mean percentages for three upper Pliocene conglom- erate pebble counts follow : Plutonic Volcanic Metamorphic Sedimentary Unknown 43 21 25 7 4 Pleistocene La Habra Formation Overlying the Pico siltstone with a marked angular un- conformity is the non-marine La IIabra formation. The actual contact is best seen on West Road east of section line F-F' (pi. 2) where the overlying La Habra formation buttresses against the upper Pliocene rocks, suggesting that the upper Pliocene sediments were tilted before the La Habra sediments were deposited. Here the basal La Habra formation is an unconsolidated reddish-brown cobble-pebble conglomerate bed, becoming finer grained toward the top. Gravel, granule sandstone, and silt beds make up the bulk of the exposed portion of the La IIabra formation. Limy deposits suggesting a lagoonal or lacustrine en- vironment crop out east of Hacienda Boulevard. No fos- sils were found in the formation. The gravel beds are well exposed along the steep slopes of the canyon overlooking Murphy Ranch. They form a series of parallel serrate ridges and valleys, presenting a badland appearance. To the extreme east of the mapped area, near Fullerton Road, the contact between the La Habra and the under- lying Pico formations is very obscure. In the citrus area west of Fullerton road a contact which may be 500 feet or more in error has been drawn. Owing to poor outcrops no attempt has been made to subdivide the La Habra formation. Wissler 23 correlates the La Habra formation with the Palos Verdes formation of upper Pleistocene age. This cor- relation is based on the diseoverv of foraminifera of lower Pleistocene age in strata underlying the La Habra, but conformably overlying the upper Pliocene siltstone in other parts of the Los Angeles Basin. Alluvium Gray alluvium of recent and perhaps latest Pleisto- cene age unconforinably overlies the La Habra formation and extends up the canyons into the south edge of the Pnente Hills. The alluvium consists of poorly sorted gray gravel, sand, and silt. STRUCTURE The mapped area is a region of tight folding and block faulting in a narrow band parallel to and north of the Whitticr fault. Many of the folds are overturned to the north. South of the Whitticr fault the strata form a south- dipping homocline, dipping less steeply away from the fault. Faults The main structural feature in this entire region is the Whitticr fault or fault zone, which starts west of the map- ped area at the Whitticr Narrows and extends approxi- mately 30 miles to the southeast. In the mapped region the principal fault is apparently a high angle reverse type with the north side thrust over the south side at an angle of approximately 70 degrees. The maximum vertical dis- placement at the- mouth of Turnbull Canyon, using data from U. S. Geological Survey Preliminary Map 83, is about 7,000 feet The lower Pnente siltstone member is faulted against the Sycamore Canyon formation in this area. This throw is distributed among two or three ana- stomosing faults, of which the southernmost is the prin- cipal one. Bailey Willis,- 4 writing of the Whitticr or Pnente Hills fault, said, "It is worthy of special note that movements on the Pnente Hills branch are dominantly in the strike- slip direction." Two lines of evidence in the mapped area support this statement. Turnbull Canyon and the Arroyo 23 W'issler, op. cit. 24 Willis, Bailey, San Andreas rift in southwestern California: Geo!., vol. 46, p. 1044, 1938. Jour. 12 Special Report 18 of La Miranda Creek are offset to the east, and the en- echelon orientation of the minor folds north of the Whit- tier fault suggests a right-lateral movement of the Whit- tier fault. No accurate figure can be given for right-lateral movement ; however, the stream offsets are measured in some few thousands of feet. A series of elongated fault blocks is mapped north of the Whittier oil field. One possible method of genesis for the Repetto (?) block north of the principal Whittier fault is suggested in figure 18. Another group of fault blocks is found in the easternmost part of the mapped area. The homoclinal area south of the Whittier fault is cut by at least one fault, which displaces the Hoover con- glomerate and the Repetto formation. A recent road cut has revealed a slickensided surface suggesting strike slip movement. Computations show that the slickensides prob- ably indicate only the last movement of the fault. A few minor faults are shown in the eastern portion of the map south of the Whittier fault. Figure 10. Oyster bed in upper Pliocene rocks east of Hacienda Boulevard. Beds are dipping to the south. Folds A narrow belt of tight folds, many of them overturned, extends along the north side of the Whittier fault. Figures 4, 15 and 16 illustrate overturned folds. The large over- turned syncline in figure 4 is probably the best example. Section E-E' (pi. 2) sections the "S" fold in figure 17. Daviess and Woodford 25 show a fault cutting off the overturned limb of the overturned syncline forming the top of the "S." The writer suggests that the sudden dis- appearance of the sandstone bed outlining the fold may be due to a sharp chevron fold as shown on the map. The beds immediately south of the Whittier fault are locally overturned to the north. A gently dipping anti- cline and syncline are shown in section E-E' (pi. 2) south of the Whittier fault. The Fullerton Oil Company has several pumping wells on the axis of the inferred anticline. Subsurface Structure Plate 2 shows the continuation of the homocline south of the Whittier fault and reveals a thinning of the Repetto formation above the Cassidulina lomitensis zone (table 1, 26 Daviess, S. N., and Woodford, A. O., op. cit. F 9), which may be due not to thinning of the beds, but to a difference in the interpretation of the position of the top of the Repetto formation as indicated by field evidence and microfossil evidence. In the East .Whittier Com- munity no. 4-1 well, + he top of the Repetto formation is based on foraminiferal information, whereas the contact in the Whittier Hills is established upon a definite lithologic change. Mauley Xatland 2G said that the out- crops in the mapped area contain a shallow water mar- ginal fauna, and that considerable difficulty is experi- enced in correlating the marginal fauna with the typical fauna from deeper parts of the basin. It must be em- phasized, however, that if the contact were determined on the basis of foraminiferal evidence, the thickness of the Repetto in the Whittier Hills would be increased, and would thereby accentuate the thinning toward East Whittier Community no. 4-1 well. Age of Faulting and Folding Evidence of three disturbances since the Miocene epoch is found in the mapped area : the earliest, an early Pli- ocene movement along the Whittier fault, is indicated by unusual sedimentary clasts in the Repetto rocks in the mapped area. Such clasts are abundant south of the fault, but rare north of it ; it is suggested that the clasts were deposited by turbidity currents originating on a steep slope formed by movement along the Whittier fault. The second post-Miocene disturbance for which evi- dence was found is a pre-La Habra (upper Pleistocene?) movement, as shown by the angular unconformity be- tween the La Habra formation and the upper Pliocene Pico formation. The most recent movement, post-La Habra in age, is indicated by the fault contact of the La Habra formation and the upper Miocene rocks along the Whittier fault in the east of the mapped area, accord- ing to Woodford, 20 and by the dip of the La Habra beds in the mapped area, in some places as great as 36°. -° Oral communication, 1950. Figure 11. Roadcut showing angular unconformity between La Habra formation and underlying upper Pliocene siltstone. The con- glomerate is dipping less steeply than the siltstone. AViiittii:r-La IIaijka Area 13 Figure 12. Unconformity in La Habra formation in sand quarry east of Hacienda Boulevard. Conglomerate bevels the underlying white grannie sandstone. PALEONTOLOGY The accompanying lists, tables 1 and 2. sliow the micro- and megafossils by locality number. The microfossils were identified by Manley Natland of the Richfield Oil Com- pany. Environment Suggested by the Fauna The approximate latitude of the mapped area is 34 degrees north. Most of the species listed thai have living representatives include this latitude within their ranges. Assuming conditions in the Pliocene epoch corresponded to those of today, the temperature of the waters at the time the megafossils were alive was similar to that in the sea off the present southern California coast. Microfossils from upper Miocene rocks have Recent representatives living at an average depth of 2000 to 3000 feet, or 335 to 500 fathoms. No megafossils were found in the upper Miocene strata. Megafossils from the lower Pliocene (Repetto) forma- tion, locality A 2, table 2, suggest shallow depths. U. S. Geological Survey locality 3907 ( Wood ring -") contains a similar fauna associated with shallow water foramini- fera, but locality A 2 is surrounded by deep water micro- fossil localities. In sharp contrast to the depth ranges of the megafossils of locality A 2 are the depth ranges of the foraminifera. An average depth range of 2000 to 4000 feet (335 to 667 fathoms). The living representatives of the upper Pliocene mega- fossil species suggest conditions of shallow waters at the time of deposition, down to 1200 feet, or down to 200 fathoms. The same general conclusion can be drawn from the living representatives of the microfossils. PETROLOGY Grouping the pebble-count localities into their respec- tive lithologic units gives the results shown in table 3. Pebble-count no. 1, from the Hoover conglomerate is placed in the Sycamore Canyon category on the basis of its rock type percentages. i7 Woodring, W. P., Lower Pliocene mollnsks and echinoids from the Los Angeles Basin, California : V. S. Geol. Survey Prof. Paper 190, 1938. The major difference between the Sycamore Canyon conglomerate beds and those of the Repetto formation is an increase in plutonic rocks in the Repetto coupled with a decrease in volcanic rocks. Locally the Repetto con- glomerates are filled with sedimentary clasts. These places were purposely avoided when the pebble-count localities were selected. Although the upper Pliocene conglomerates show an increase in volcanic rock types over the Repetto forma- tion, the increase appears to be accidental. Locality P 13 has a very high percentage of volcanics, and raises the average. The P 13 conglomerate is probably reworked from a Sycamore Canyon source. Perhaps reworking of conglomerate destroys volcanic rocks. The apparent high volcanic percentage from locality P 13 may indicate less reworking of the P-13 conglomerate. Because numerous actinolite-tourmaline granite boulders are found in it, Daviess and Woodford - s placed the conglomerate in the Syca re Canyon formation. A recent road cut has ex- posed the conglomerate ami shown it to be fossiliferous. .Many peeten fragments and oyster shells were found, and some of the boulders show tnollusk borings. The fauna has a Pliocene appearance though no definite species could he identified. Mineral analyses were made of 26 sandstones spread throughout the section both north and south of the Whit- tier fault. The primary purpose of the mineral analyses was to determine differences in the sandstones south of tin- Whittier fault. Only the most prominent and obvious minerals in the sandstones were recorded. -Minerals with similar properties are grouped together and minor con- stituents are ignored. The upper Pliocene and Repetto samples have very similar contents. The Repetto sands differ slightly in that they have a somewhat higher percentage of minerals having a specific gravity greater than 2.87. The Sycamore Canyon | S i sands south of the Whittier fault from both the Hoover conglomerate and the Central Pee sandstone show an even greater proportion of min- ■- Daviess, s. \\, and W Iford, A. < > . op. i upper Pliocene or loner Pleistocene Cassidulina cushmani Globigerina sp. Nodogenerina advena Nodosaria arundinia Pseudoparella pacifica Uvigerina peregrina A la Cardita ventricosa Crepidula princeps Pecten (Janira) cf. bellus var. hemphilli A lb Conus sp. Crepidula princeps Epitonium tinctum Laevicardium sp. Mactra sp. Nassarius sp. Neverita reclusiana Pecten (Janira) cf. bellus var. hemphilli Tegula sp. Tritonalia cf. foveolata Turritella cooperi Dentalium sp. A lc Calyptrea sp. Crassitellites sp. Crepidula cf. princeps Laevicardium (Trachycardium) cf. quadra- genarium Lucina acutilineata Pecten sp. Pecten (Janira) cf. bellus var. hemphilli Tagelus sp. A 2 Area (Anadara) cf. trilineata Fusitriton cf. oregonensis Lucina sp. Ostrea vespertina Pecten (Lyropecten) estrellanus var. cer- rosensis Pecten (Patinopecten) dilleri Pecten (Pecten) cf. hastatus Pecten (Pecten) cf. islandicus var. jordani A 3 Cardita ventricosa A /, d 5 Lunatia lewisii Pecten (Janira) cf. bellus var. hemphilli Pecten (Patinopecten) cf. healyi Ostrea vespertina Careharodon sp. Uvigerina senticosa Valvulineria araucana F 35 upper Pliocene Globigerina sp. Pseudoparella pacifica I'vigerina cf. hootsi Valvulineria araucana F 36 Miocene or Pliocene Bulimina cf. ovula Chilostomella ovoidea Klphidium cf. peoyanum Gyroidina Boldanii var. rotundimargo Valvulineria vilardeboana var. glabura Virgulina sp. F 37 upper Mohnian Bolirina woodringi Table 2. Megafossih * .4 G Calyptrea sp. ( '(puns cf. californicus < Jrepidula cf. princeps Fusitriton cf. oregonensis Lora pyramidalis Mitra sp. Pecten sp. A 7 Crepidula cf. princeps Lucina sp. Nassarius sp. Pecten ( Pecten ) cf. bastatus .4 8 Ostrea sp. Pecten sp. .1 !) Cancellaria sp. ( lardita ventricosa Laevicardium (Trachycardium) cf. quadra- genarium Nassarius perpinguis Pecten (Janira i bellus var. hemphilli Pecten (Patinopecten) healyi Pododesmus macroschisma J to Pecten (Patinopecten) healyi I // Pecten (Janira) cf. bellus var. hemphilli Schizothaerus nuttalii Tivela stultorum .1 12 Cantharus cf. fort is Cardita ventricosa Crepidula princeps Laevicardium sp. Lunatia lewisii Nassarius perpinguis Pecten (Janira) cf. bellus var. hemphilli Pecten (Patinopecten) healyi Pecten (Pecten) cf. hastatus Spirotropsis (Antiphancs) aft", perversa Terebra cf. elata Turritella cooperi Buliminella subfusiforms Globigerina sp. FS8 Miocene Bolivian vaughni Globigerina sp. F Jfl upper Pliocene Cassidulina californica Gaudryina arenaria Pseudoparella pacifica Textularia sp. Uvigerina cf. hootsi F bO upper Pliocene Gaudryina arenaria Globigerina sp. Pullenia i|tiiii(]ueIoba Pseudoparella pacifica l'\ igerina opunsia .1 13 Pecten i Janira) cf. bellus var. hemphilli Pecten ( Pat inopecten ) cf. healyi A 1', Area (Anadara) cf. mult icostata Cancellaria aft", tritonidea 1 to ( isi res \ esperl ina Pei ten (Janira) cf. bellus var. hemphilli Pecten (Pecten) islandicus var. jordani .! II! Pecten (Janira i cf. bellus var. hemphilli A n Calj ptrea sp. Crepidula princeps Laevicardium i Nemocardium) centifilosum Pecten (Aequipecten) circularie Pecten (Janira) cf. bellus var. hemphilli Pecten ( Pat ninpeclen I heal] i Pecten ( Pecten) islandicus var. jordani Pecten ( Pecten ) hastatus Si.len sp. A 18 I rendraster cf. excentricus .1 in Crepidula sp. Ostrea vespertina Pecten (Janira) cf. bellus var. hemphilli .4 20 Clavus sp. ( 'mms californicus Lunatia lewisii Nassarius insculptus Ne\ erita reclusiana ( )st ica \ esperl ina Panope generosa Pecten (Aequipecten) circularis Pecten (Janira) cf. bellus var. hemphilli Pseudomelatoma pencil lata Solen sp. Turritella cf. pedroensis A 21 Pecten (Patinopecten) healyi • All the megafossil localities are In the Pico formation except locaJity A 2, which is in the upper Repetto. 16 Special Report 18 Table 3. Results of Pebble Counts. Sycamore Canyon formation Locality number Plutonic 1 40 7 40 9 36 12 48 Average 41 Repetto formation Locality number Plutonic 2 56 3 54 4 68 5 76 6 42 8 70 10 66 11 66 Average 62 Volcanic Metamorphic Sed linen tary Unknown 28 18 2 12 34 8 18 38 8 2 16 30 10 12 32.5 11 1 14.5 Volcanic Metamorphic Seel imei] tary Unknown 10 8 4 22 22 14 10 18 6 2 6 8 6 10 20 10 12 16 2 14 12 10 8 2 16 10 6 18 12.6 2.5 14 Upper Pliocene formation Locality number Plutonic 13 32 14 54 16 42 Average 43 Volcanic Metamorphic Sedimentary Unknown 38 12 10 8 8 26 8 4 18 36 4 21 25 La Habra formation Locality number 15 Plutonic Volcanic 13 Metamorphic 36 Sedimentarv Unknown erals having' a specific gravity higher than 2.87 ; in addi- tion, they have a much higher biotite content, a correspond- ingly lower epidote group content, and a large percentage of garnet in the heaviest separation. However, these two samples are not similar to the one analyzed Sycamore Canyon sand sample, taken from the fault block shown in section B-B' (pi. 2). Perhaps the differences are local, and would be less marked if more analyses were made of samples from Sycamore Canyon formation. The high percentage of unknown pebble types in the Sycamore Canyon and Repetto formations is probably a reflection of the low percentage of metamorphic rocks. Most of these pebbles were so rotten that they were shat- tered upon being struck with a hammer. The only conclusion which may safely be drawn from these results is that the sands south of the Whittier fault mapped as Sycamore Canyon appear to differ widely in mineral content from the overlying Pliocene sandstones. Whether there are comparable sands north of the Whit- tier fault was not determined. The mineral compositions of all the sand samples studied classify them as arkose. Rocks with a relatively high silica content and a low percentage of mafic minerals are suggested as a source for the sandstone. Because of the approximately equal percentages of orthoclase and plagioclase, rocks with a composition of that of quartz monzonite or quartz monzonite-gneiss are proposed as possible source rocks. Source of Conglomerate and Sandstone. Bellemin 29 suggested the San Gabriel mountains as a possible source area for the Whittier conglomerate beds. He studied the conglomerates northwest of the mapped area. Olmsted 30 suggested the west central San Gabriel Mountains as an important source region for the conglomerate in the San Jose Hills throughout upper Miocene and Pliocene times. The strong similarity between the conglomerate beds of the mapped area and those mapped by Olmsted 31 has been mentioned previously. Thus, the central San Gabriel Mountains are tentatively suggested as the source for the conglomerates of the mapped area. The typical silica- rich rocks of the central San Gabriel Mountains would be capable of furnishing the constituents for the arkosic sandstones of the mapped area. DEPOSITION OF REPETTO FORMATION The Repetto formation poses some interesting problems : (1) the local abundance of angular sedimentary clasts in the conglomerate beds; (2) the presence of shallow water and deep water faunas in a single set of beds, sug- gesting the sliding of shoal sediments to deep water ; and 59 Bellemin, G. J., Petrology of Whittier conglomerates, southern Cali- fornia : Am. Assoc. Petroleum Geologists Bull., vol. 24, pp. 649- 671, 1940. 30 Olmsted, F. H., Geology and oil prospects of western San Jose Hills, Los Angeles Countv, California : California Jour. Mines and Geol.. vol. 46, pp. 191-212, 1950. 3' Olmsted, P. H., op. cit. Whittier-La Habra Area 17 PlGUBE 14. Fault contact between upper Puente ln-e/£f set O,/ Afap Mo 39, West Coyote