Abstract Three geologic case histories of freeway landslides in California offer significant guideposts in the sound economic planning of freeways. The three case histories are (1) San Diego Freeway, Bel Air, Los Angeles (Interstate 405; cut-slope and ancestral block glides); (2) Pomona Freeway (State Highway 60; cut slope block glides in areas previously unslid); and (3) Golden State Freeway, West Fork, Liebre Gulch (Interstate 5; fill slope in area of previous sliding). The San Diego Freeway along Sepulveda Canyon in the Bel Air area of Los Angeles has been beset with landslide problems in the Santa Monica Formation (Triassic-Jurassic) since its construction in 1961-62. Because this area is predominantly slate, proper positioning of this stretch of the freeway could have eliminated much remedial grading and redesign. A 1.6-km stretch of Pomona Freeway west of its junction with State Highway 71 has been subject to landsliding of the Puente Formation (upper Miocene) since construction. Freeway cuts had to be flattened appreciably and new rights-of-way established. The Liebre Gulch landslide along Interstate 5 occurred when road fill was placed at the head of an undetected ancestral landslide. These three case histories not only underline that the public right-of-way for freeways has not been given adequate geologic attention, but that it represents one of the most neglected opportunities in the application of geology to highway selection, design, construction, and maintenance.

Parts I to III of the paper describe faunas of fossil fish from different horizons of the Los Angeles Basin. Part I. Collections of fish fossils were made at a number of localities on the west side of Sepulveda Canyon, Santa Monica Mountains, California. The fishes occur in hard siliceous sandstone and shale of the lower Modelo formation (Upper Miocene). Eighteen families and twenty genera are represented. The assemblage suggests a marine neritic subtropical fauna, living at a depth of 100 to 200 m. Part II. The diatomaceous shale of the Upper Modelo formation yielded an abundance of fossil fish at localities near Van Nuys along the northern rim of the Santa Monica Mountains. Strata containing fish remains interfinger with barren layers of volcanic ash, sandstone, and mudstone. The restricted fauna of a bathypelagical environment is represented by nine genera. Nearly all are present with a great many specimens. A fauna transitional between the Upper and Lower Modelo is found in platy shale conformably underlying the Upper Modelo. Part III. Fossil fish have been found in marine deposits of late middle to early Upper Miocene age (Altamira shale) on the coast of the Palos Verdes Hills, near San Pedro, California. A subtropical shallow sea is indicated as the place of deposition of this particular assemblage. The fauna of the Altamira shale is yet incompletely known, and fishes are also present in the overlying Valmonte member of the Monterey formation. Part IV. The herringlike fishes of the California Miocene are reviewed. This type of fish is the most common in the Miocene deposits. The clupeoid fishes have undergone considerable changes in the California sea since Miocene. Part V. Represents a study of the Zaphlegidae, a family of the Scombroidei belonging to the first division of the suborder, the Trichiuriformes. The family, evidently extinct, was related to the Gempylidae and lived in offshore deeper water. The reasons for its extinction were possibly climatic changes toward the end of the Miocene. Part VI. Gives a complete revision of the fish fauna from the diatomaceous earth of Lompoc, Santa Barbara County, California. The fauna comprises 31 families, 39 genera, and 42 species. It represents a harmonious assemblage that accumulated in a warm-temperate coastal sea of 25 to 50 fathoms depth, half a mile away from shore. Greater similarity existed between the fish faunas of the Pacific and Atlantic Coast of America during the Miocene than at present. A relatively great number of fish forms has become extinct in the California sea since Miocene times. Bathypelagical types were established best. Local changes probably caused the extinction of most of these types.

ABSTRACT The Beechers Bay Formation of medial Miocene age consists of a sequence of generally coarse-grained volcaniclastic sediments which crop out on Santa Rosa Island, California. This unit was deposited on a deep-sea fan very near an active volcanic source. The Beechers Bay Formation is the timestratigraphic equivalent of the Monterey Formation. It is divided into five informal members which were deposited as distinct lithofacies on the deep water fan. Members A (oldest) and E (youngest) are composed of dacite-andesite conglomerate, basalt conglomerate, and interbedded pebbly sandstone, all deposited on the inner (upper) fan. Members B and D were both deposited in the channeled portion of the upper mid-fan. Member B consists of feldspathic dacite-andesite litharenite and interbedded siltstone. Member D is a true volcaniclastic sandstone that signifies an increase in volcanic activity at the nearby source. Member C is a rhythmically bedded sequence of feldspathic volcanic litharenite and siltstone which was deposited on the distal mid-fan. All members of the Beechers Bay Formation contain blueschist clasts thought to have been derived from the Catalina (Franciscan) Schist. Paleoslope and paleocurrent indicators found in each member suggest the source area was located to the present-day eastnortheast. The source area was a volcanically active area distinct from that which produced correlative volcanics on Santa Cruz Island and in the Santa Monica Mountains, located south of the present location of Santa Rosa Island. This area produced large quantities of dacitic and andesitic material which was deposited by sediment gravity flows on an adjacent submarine fan. The metamorphic material was shed from a nearby exposure of Catalina Schist and related rocks.