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Beets . owe ye "vary hAd Lange Nee TT era § Te AAR APP kk University of California Publications in GEOLOGY VOLUME XII {919-1921 EDITORS ANDREW C. LAWSON JOHN C. MERRIAM |” 269TIS” if) UNIVERSITY OF CALIFORNIA PRESS BERKELEY, CALIFORNIA CONTENTS PAGE . Geology of a Part of the Santa Ynez River District, Santa Barbara County, California, by William S. W. Kew ........0......20222..--::21:0-:0-e0--- . Cretaceous and Cenozoic Echinoidea of the Pacific Coast Region of INorthwAmenica bye swale gs: Wier WG yy eececaccscevecsenscce cece cuccneteeeecseeceesenes . An Outline of Progress in Palaeontological Research on the Pacific Coastrby diohny C.> Merri aia sss asco ce ee cece nore secon ctececcasecseseeee sees . An Early Tertiary Vertebrate Fauna from the Southern Coast Ranges Ob a@aliitornias iby) Chester StOCK 22 seccece cere cececes ceeeee eeaces slekeceeeseusesecseecser cee 5. Extinet Vertebrate Faunas of the Badlands of Bautista Creek and San Timoteo Cafion, Southern California, by Childs Frick .................2...... . A Mounted Skeleton of Mylodon harlani, by Chester Stock -................... . The Mobility of the Coast Ranges of California. An Exploitation of the Elastic Rebound Theory, by Andrew C. Lawson .....................- 237 OLOGY OF A PART OF THE SANTA YNEZ RIVER DISTRICT, SANTA BARBARA _ COUNTY, CALIFORNIA » 7 SS Sy 4 3 ‘ BY i : 7 - WILLIAM S. W. KEW E es ? _ UNIVERSITY OF CALIFORNIA PRESS _ BERKELEY te UNIVERSITY OF CALIFORNIA PUBLICATIONS Note.—The University of California Publications are offered in exchange for the publi- cations of learned societies and institutions, universities and libraries. Complete lists of all the publications of the University will be sent upon request. For sample copies, lists of publications or other information, address the MANAGER OF THE UNIVERSITY PRESS, BERKELEY, CALIFORNIA, U. S. A. 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Fauna from the Type Locality of the Monterey Series in California, by Bruce Martin. 10¢ 8. Pleistocene Rodents of California, by Louise Kellogg .......2..21..2---:ceuccecceeeceeceeeneeenereeensene 15¢ 9. Tapir Remains from Late Cenozoie Beds of the Pacifie Coast Region, by John C. ; INTOY IAMS -.. .,.--2..--2neg-docd-b- 0b tonne cohen atatecesecedeceseioneteaedet a eaves J) SE ee 10e 10. The Monterey Series in California, by George Davis Louderback ................------.-00s+--= 65e 11. Supplementary Notes on Fossil Sharks, by David Starr Jordan and Carl Hugh Beal. 10¢ 12. Fauna of the Eocene at Marysville Buttes, California, by Roy E. Dickerson ........ 45¢ 13. Notes on Scutella norrisi and Seutaster andersoni, by Robert W. Pack .........-...---2.. 5¢e 14. The Skull and Dentition of a Camel from the Pleistocene of Rancho La Brea, by TOWN CH Merriam « x._..25r.c..cctiaseecceaceensocteen cesses ooceyseeecttes cstensteteeenatnns oe er 20c 15. The Petrographic Designation of Alluvial Fan Formations, by Andrew C. Lawson.... 10¢ 16. A Peculiar Horn or Antler from the Mohave Miocene of California, by John C. Mer- TAM: hon oo esd ct cnccesces steel cencae-beendentecccnetoncdeusnssnndociechancarnosbescase cletastt oe ieee tt es a 5c 17. Nothrotherium and Megalonyx from the Pleistocene of Southern California, by Chester ‘Stock i.2 22.22 enecencscsnsssentieecaenedueenuesetacseitoce:ieencdcceesthetecetcare=: Stan ea aa 15¢ 18. Notes on the Canid Genus Tephrocyon, by John C. Merriam .............-..-.-2---0-2e-e--cene-ose== 15¢ 19. Vertebrate Fauna of the Orindan and Siestan Beds in Middle California, by John CPeMi@ prim oe... Sscciee ios deen n ates aceb bona decabentusecSaxbcbens tan dee ates Pees ee 10¢ 20. Recent Observations on the Mode of Accumulation of the Pleistocene Bone Deposits of Rancho La Brea, by Reginald ©. Stoner <2... see ee ee 10c 21. Preliminary Report on the Horses of Rancho La Brea, by John C. Merriam ............ 20¢ 22. New Anchitheriine Horses from the Tertiary of the Great Basin Area, by John C. Merriam 23. New Protohippine Horses from Tertiary Beds on the Western Border of the Mohave Desert, by John C.. Merriam 200.2: .c25.2c.ceccebeceseh ates cee encode ne 24. Pleistocene Beds at Manix in the Bastern Mohave Desert Region, by John P. Bupa day 228 Shscsce ieee Se ca ceeeeckecsnedencbaanodaseae da onu eh ete ccna aa 25. The Problem of Aquatic Adaptation in the Carnivora, as Illustrated in the Oste- ology and Evolution of the Sea-Otter, by Walter P. Taylor ............c.s.---scsensnensesenee- a” UNIVERSITY OF CALIFORNIA PUBLICATIONS BULLETIN OF THE DEPARTMENT OF GEOLOGY Vol. 12, No. 1, pp. 1-21, plates 1-2, 2 text figures November 20, 1919 GEOLOGY OF A PART OF THE SANTA YNEZ RIVER DISTRICT, SANTA BARBARA COUNTY, CALIFORNIA BY , he WILLIAM S. W. KEW ( CONTENTS PAGE bo Mat OMUCHOM ..-sesocs..5.teeseecoeee scenes eee Location and topography... Stratigraphy...........0..c.e--: oe Seats Satter Ste: eae Ft aaa east A nee Re General features............. Zia a A A re ee er ak dee Jurassic (?) system............. FrancisCan. S€TICS...0....05..0c.0cecceseceeccecessecseescvscvescaeenevarenscasees Cretaceous system........0.000.00.. Shasta and Chico rocks........ Tertiary system... : Eocene series........0..0.0.0..... Tejon formation... Oligocene (2) sSCVICS ie. acc tececcsscen cee seeves cscs ecseessassssdueteesdseeesevssesazsefscssiyssiedesietsss Sespe formation...... A ee bee) 1 Miocene series.............. pea aceasta re ee eee Monterey group........ ee Bic, Lge eet aa ore LS General features........ ee ere : Re eisca Peet cee ee eS Vaqueros sandstone... ccc ccccceeveveveeeveveesevevevesvevsveveveeees 18} Salinas shale............ ; eee cn te ee eee re ao 14 Pliocene series......000.0.0.00... eee eae eee O15 Fernando formation: aft ser eect cence tack ee ae me 5 Quaternary system... cceccecceeee eee eee eee a: at 16 Terrace deposits......0..0000.000ccccee. eee ee eee ee re eG ISUNUCCUMC eter si csescsscvssseuseeeestetons Fe eee ee aaa aera cee Gemeraltrea tunes it sssgstoa)s.t casasanisscossabesnereieveceatseieushridcactewortatsaocess nitive LG Detailed structure........000occccccccccececscsceseecscstteceveeeeees eee eer eee rer ee 77 Tittle Pine Mountain area...........cccccccscccccccesecesscsrsveseesssvecsvecsesessasersesssevsvseacseee, 17 DSAMGAy YMEZ RAVE ALCAc.c....cccceecessessovessosccrvecesesescesseestecistpevsofesesservsesseretetesveenes 19 RS ATibee MOLE Ze WAOUMCAMIS ANCE, vss. cxssnvcsseiacossacivevsstatictesssssatagsadiptaceansarsbseastvhetteaceee 20 GOTCIUISI OH Senet oh oh caterele ac Heiss wansten wcoruas il sheatas Mineftavsvisttooeleseican «sas sedtteciitlciaiee 21 iw) DAD © C0 CO oOo oO — bo 2 University of California Publications in Geology — [Vou. 12 INTRODUCTION The first investigation of the Santa Ynez River district was under- taken to obtain, if possible, some palaeontologic or stratigraphic evidence as to the age of the Franciscan rocks which are exposed in this region. With this end in view, the writer, together with Mr. N. lL. Tahaferro, spent two weeks during June, 1914, in the vicinity of Redrock Canon, which is a tributary of the Santa Ynez River in the western part of the district. Unfortunately, the Franciscan series in this region, as in other places, proved to be barren of any evidence which would indicate its age. Nevertheless, the country afforded some interesting problems, the study of which has given some information that is a contribution to the stratigraphy of California. An important structural question presented was the cause for the difference in direc- tion between the Santa Ynez Mountains and the San Rafael Mountains. To investigate this two more trips were made, one in the summer of 1915 with Dr. E. F. Davis and the other in 1916 with Mr. K. H. Schiling. To both of these gentlemen, the writer is under obligations for the use of their notes. Acknowledgement is made to Professor A. C. Lawson, under whose supervision this work was carried on, for valuable eriticism and advice. The writer also takes this opportunity to thank the U.S. forest rangers of the Santa Barbara National Forest for their uniform courtesy. LOCATION AND TOPOGRAPHY The area to be described lies in the southern part of Santa Barbara County, California, and extends fifteen miles north from the Santa Barbara Channel with a breadth of about eighteen miles, forming a rectangular area of approximately 270 square miles. The northern part, where most of the work was done, is in the southern portion of the Santa Ynez quadrangle, and the remainder is covered by the Santa Barbara and Goleta Special maps. The term ‘‘Santa Ynez River district’’ as used in this paper includes the southern half of Santa Barbara County. It also embraces a portion of the Santa Ynez Mountains and the southern slope of the San Rafael Mountains, the latter being a local division of the California Coast Ranges. 1919] Kew: Geology of a Part of the Santa Ynez River District 3 35° jae |} cata’ Area mapped and dis- cussed in this report. Areas on which reports / : EA 6 have been published. a = X ae Na INDEX TO PUBLISHED REPORTS SS SS ZZ . Cuyama Valley (U.S.G.S. Bull. 621) Summerland (U.S.G.S. Bull. 321) ae eo bo . Santa Maria (U.S.G-.S. Bull. 322) . Santa Clara Valley (U.S.G.S. Bull. 309) . McKittrick-Sunset (U.S.G.S. Bull. 406) . South end of San Joaquin Valley (U.S.G.S. Bull. 471) . Los Angeles (U.S.G_S. Bull. 309) . Puente Hills (U.S.G-S. Bull. 309) . Santa Ynez River San Diego m weanonanw iigis 118° 100 miles = _ Fig. 1. Index map of a part of California, showing location of area discussed in this report and areas on which reports have been published. 4 Umiversity of California Publications in Geology [ Vor. 12 The San Rafael Mountains have the same northwesterly trend as the Coast Ranges in general. They are extremely rugged and quite irregular, since they are made up of a series of ridges usually deter- mined by the strike of the strata of which they are composed. The main crest rises to an elevation of 6828 feet in Big Pine Mountain and 6581 feet in Mission Pine (San Rafael) Mountain. Within the area studied, Little Pine Mountain (4174 feet) is the highest elevation and is the culminating point of a long ridge which extends northwesterly from Indian Creek to Santa Cruz Creek. Loma Alta Mountain (2745 feet), although comparatively low, forms a prominent landmark in the western border of the area. The Santa Ynez Mountains rise abruptly from the low, broad ocean terraces on the south to a comparatively even crest line with an average height of about 3500 feet. The greatest elevation is Santa Ynez Peak, 4292 feet high. The range is very narrow and extends from Point Arguello, just north of Point Conception, for forty miles in an easterly direction to a junction with the Coast Ranges proper. In its entirety, the range is very simple, being made up of a remark- ably straight, single ridge, which has practically no large spurs or canons. The drainage of this district is concentrated in the Santa Ynez River which lies in the triangular-shaped lowlands between the two ranges. Its course runs nearly west for its entire length at the north- ern base of the Santa Ynez Mountains. The upper part of the river is confined in a narrow canon, but to the west it gradually widens out, until opposite Loma Alta Mountain the bed of the stream forms but a small part of a widely terraced flood plain. In no part within the area studied is the river now corrading its trench; on the contrary it appears to be engaged in the work of aggradation. The tributaries entering the main stream reach back to the main divide, a distance of about ten miles or more. The most important of these are Mono Creek and Santa Cruz Creek. These streams cut across the strike of the formations, whereas Buckhorn and Gamusa creeks follow the trend of the strata. All the north side streams are low grade and in only a few places are they corrading vertically. In some of the larger canons, as the Mono, there are terraces representing former flood plains of the stream. In marked contrast to the drainage on the north side of the river, that of the Santa Ynez Mountains is short, high grade, and incisive. Some of the streams are so steep that it is impossible to ascend the canons as they are blocked by huge boulders and stepped by waterfalls. 1919] Kew: Geology of a Part of the Santa Ynez River District ) Quaternary terrace gravels and alluvium. Fernando formation (Pliocene) 3000’+ Sandstone and conglomerate; marine at base, but terrestrial in upper part. cherts and clay shales. Vaqueros formation, 3400+ feet of massive sandstones fol lowed by shaley fine-grained sandstones impregnated with petroleum, Monterey group (Miocene) 4000’ + Salinas shale; 6000+ feet of 9:9.52-0+0-0-0-0.0 * spe Fanglomerate, varicolored mas sive, cross-bedded sandstone, and soft red-and green con- glomeratic sandstone. Sespe formation (Oligocene?) 1700’ + Thin-bedded sandstone. Tejon formation (Eocene) 2800’+ Buff-colored massive sandstone. Gray shales and thin-bedded sandstone. Upper member; sandstone, shale, aarti : and massive conglomerate. Shasta and Chico rocks (Cretaceous) 8000’ + oo ° Cis S6) OS. Lower member; greenish shales and minor thicknesses of thin- bedded sandstone and conglom- erate, Complexly folded and broken sandstone, radiolarian chert, and shale, Franciscan series (Jurassic ?) Larsely intrusive serpentine, basalt, and gabbro, Fig. 2. Columnar section of strata exposed in the Santa Ynez River district, California. 6 University of California Publications in Geology [ Vor. 12 STRATIGRAPHY GENERAL FEATURES The formations exposed in the area are of sedimentary origin, with the exception of a few igneous rocks in the Franciscan series (Jurassic?). These rocks are the oldest in the district and are made up chiefly of sandstones, shales, and radiolarian cherts similar to those of the type section around San Francisco Bay. The Cretaceous is represented by conglomerates, sandstones, and shales which are in part of Knoxville (Lower Cretaceous) and Chico (Upper Cretaceous) age. The Tertiary comprises three groups of rocks. The Eocene is represented by the Meganos and Tejon formations (Middle and Upper Eocene), no Martinez (Lower Eocene) being recognized. Uncon- formably above the Tejon is the Sespe formation (Oligocene?) which is probably of continental origin. This is followed by the Monterey group (Miocene) in conformable sequence. The Fernando (Pliocene) formation overlies these with a marked unconformity; this is in the main of marine origin, but towards the upper part passes into fresh water clays, sandstones, and conglomerates which may be equivalent to the Paso Robles formation to the north. Pleistocene terrace deposits are common along the Santa Ynez River, and remnants of them are present as high as 1500 feet above the level of the river JURASSIC(?) SYSTEM FRANCISCAN SERIES The Franciscan series as exposed in the northern part of the Santa Ynez district occurs in two areas, one considerably larger than the other. The larger area extends along the southern slope of Little Pine Mountain and is a continuation of the Franciscan series mapped in the Santa Maria oil district.1 Towards the east, near the big bend in the river, it becomes only a narrow strip marking the course of a fault. 1 Arnold, Ralph, Geology and oil resources of the Santa Maria district, Cali- fornia, U. 8. Geol. Surv. Bull. 322, 1907. oe ; 7 = ; : : < m _ [KEW] VOL, 12, PL. 1 UNIV, CALIF. PUBL, BULL. DEPT. GEOL, LEGEND 2) SISSYENE AMYNNILWNO ABVILYIL ‘SNO3D¥19ud Pei ca 2 SE 2. gE e32 was =) Se 223 23: ae Sa Eas il Eze Bi a 3 > an 3= Se 25 e 233 Ess Se = g3< 3 1| 3 sz g3* ges Ply azs g2f ee bés ese ia dH oH 2? 3 Se a a Axis of syncline After Arnold. 16S Bul] 321 and after R. Arnold, U.S.G.S. Bull, 321 Geology by W.S.W. Kew, GEOLOGIC MAP OF A PART OF THE SANTA YNEZ RIVER DISTRICT. SANTA BARBARA COUNTY, CALIFORNIA terval 250 fect To pov rene webs naes tga gh le 1919] Kew: Geology of a Part of the Santa Ynez River District 7 The sedimentary strata? of the Franciscan series mainly consist of sandstones and radiolarian cherts with a minor amount of shale. The sandstones are massive, dark green in color, and arkosic. As a whole, they show a marked similarity to those typically exposed around San Francisco Bay. The cherts occur in relatively small patches, usually as inclusions in the igneous rock, though they have been observed as lenses in the sandstone. They show the characteristic banded struc- ture and in some places are nodular. The shales occur mainly in a small area at the head of the middle branch of Redrock Canon and are gray in color, rather soft, and contain numerous limestone nodules. They resemble the Knoxville shales, but when traced to the east, are seen to le between beds of typical Franciscan rocks, such as the radiolarian cherts. All the igneous rocks are of the basic type consisting mainly of basalt and serpentine with gradations into coarser grained diabase and gabbro. The basalts have the characteristic pillow structure so common in a similar rock of the San Francisco area. They are intrusive in the sandstone, shale, and chert, as dikes, sills, and small laccoliths, but have produced very little contact metamorphism. All the in- trusions follow the general strike of the Franciscan rocks, that is, a northwesterly direction. On account of the great degree of disturb- ance caused by the intrusion of the igneous rocks and later deforma- tion, no attempt was made to separate the different rocks on the map. The laccolithie structure is shown in the small area of basalt which forms the red rock from which the canon of that name is taken. The upper surface of this rock mass is rounded while the lower side or bottom forms a steep almost overhanging cliff. Although on a very small seale, this body of rock resembles closely a typical laccolith. Serpentinization has not proceeded so far in some cases as in others, the less altered rock containing numerous large bastite erystals and some residual olivine. A serpentine, hydrometamorphosed to a silica- carbonate rock,* is exposed along the fault which parallels the Santa Ynez River. This is usually a brown hard mass which shows very little of the original serpentine. Cinnabar occurs in this and it has been mined in a small way for many years. 2A more detailed account of the sandstones and cherts occurring in this area may be found in two papers published by FE. F. Davis, The Franciscan sandstone, Univ. Calif. Publ. Bull. Dept. Geol., vol. 11, pp. 1-44, 1918, and The radiolarian cherts of the Franciscan group, Univ. Calif. Publ. Bull. Dept. Geol., vol. 11, pp. 235-432, 1918. 3 Knopf, Adolph, An alteration of serpentine, Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, pp. 425-430, 1906. 8 University of California Publications in Geology [ VoL. 12 CRETACEOUS SYSTEM SHASTA AND CHico Rocks The Cretaceous strata resting unconformably upon the Franciscan series can be separated into two divisions: first, a lower series consist- ing mainly of shale interbedded with thin sandstones and a small amount of conglomerate; and secondly, an upper series of strata made up, for the most part, of sandstone with minor intercalations of shale and conglomerate. An unconformity between these two series is suggested by the presence of a heavy conglomerate at the base of the upper member, together with the fact that there is a sharp change in lithology from beds below the conglomerate to those lying above, and a slightly irregular contact between them. The lower beds are definitely known to be of Knoxville (Lower Cretaceous) age since Aucella piochi (Gabb) occurs abundantly in them. The upper beds may represent the Chico (Upper Cretaceous), though no fossils have been found to prove this statement. In detail, the lower or shale strata consist of greenish black shale with minor amounts of interbedded sandstone and limestone. The sandstone is of a lighter color, fine to moderately coarse grained. The beds of lmestone are quite impure, black to dark in color, and six to nine inches thick. About 300 feet stratigraphically above the base is a fifteen-foot bed of fine conglomerate, the pebbles of which average about one-half inch in diameter, though some are as large as a hen’s egg. They are derived mainly from quartzite, black chert, and igneous rock. The upper fifty feet of the shale member consists of coarse sandstone formed of subangular grains of quartz, biotite, and serpentine. Marine fossils are present though indeter- minable. All the bedded shaley strata are greatly folded and faulted, so that in many places the deformation resembles that occurring in the sedimentary beds of the Franciscan series. The heavy conglomerate at the base of the upper series is somewhat lenticular in character, though it can be traced from the mouth of Blue Canon along the ridge south of Gamusa Canon; it again appears on the south slope of Little Pine Mountain immediately west of the Oso Canon trail. A noticeable feature of this is that it occupies the same horizon as the Oakland conglomerate on the east side of San Francisco Bay. This conglomerate is made up of well rounded 1919] Kew: Geology of a Part of the Santa Ynez River District 9 boulders ranging in size up to a foot and a half in diameter. They consist of chert, trap, porphyries, granites, and rhyolites, and are cemented by a medium-grained, dark-gray sandstone. The Cretaceous strata lying above this conglomerate consist mainly of medium-grained, dark-green sandstone which weathers reddish. Immediately overlying the heavy conglomerate, the sandstone contains angular fragments of limy shale of a composition similar to the impure limestone in the Knoxville below the conglomerate. Thin layers of dark-green shale are interbedded with the sandstone, though the latter is predominant throughout this upper member. TERTIARY SYSTEM EOCENE SERIES Tejon Formation In a publication by Eldridge and Arnold relating to neighboring districts, the name Topatopa formation has been used to designate the Eocene strata lying above the Cretaceous and below the Sespe formation and continuous with the Eocene in the Santa Ynez district. Wherever exposed it has yielded typical Tejon and Meganos (Eocene) fossils and. is therefore correlated with these formations, which are widespread over California, so that the name Topatopa becomes superfluous. At the time the field work for this report was done, the Meganos formation’ had not been recognized. Later, in checking over the fauna, characteristic species of both the Tejon and the Meganos were found. As these formations have not been mapped separately, the Eocene as it occurs in this region will be considered as a whole and called the Tejon. In the Santa Ynez River district, the Tejon forms the greater part of the Santa Ynez Mountains, and occupies a broad area immediately north of the Santa Ynez River east of Loma Alta. Its relation to the Cretaceous in this region is not clear, as in no place are the two in contact except on the south slope of Little Pine Mountain, where beds of doubtful Tejon age rest unconformably upon the Cretaceous. A typical section of the Tejon as seen on the west side of Oso Creek consists of about 2800 feet of shales and sandstones with minor 4 Hidridge, Geo. H. and Arnold, Ralph, The Santa Clara Valley, Puente Hills, ae Los Angeles oil districts, southern California, U. S. Geol. Surv. Bull. 309, 5 Clark, Bruce L., Meganos group, a newly recognized division in the Eocene of California, Geol. Soc. Am. Bull., vol. 29, pp. 281-296, June, 1918. 10 University of California Publications in Geology [ Vou. 12 amounts of limestone and conglomerate. A hard calcareous basal sandstone rests immediately upon the Franciscan series. It is locally an impure limestone, and in places conglomeratic, the pebbles being derived mainly from the Franciscan rocks and ranging in size up to four inches in diameter. Upon this basal portion are about 1400 feet of bluish-gray shales, which weather readily into a fine clay soil form- ing low rounded hills and saddles on the ridges. -Interbedded with this shale are layers of micaceous, rather coarse-grained sandstone, usually about an inch thick. These weather out of the shale and remain as thin flags on the surface. The following fossils, which show that it is of unmistakable Tejon and Meganos age, have been obtained within this shaley member : FOSSILS FROM THE EOCENE oO oD a oD oF oO on oF Schizaster, cf. diabloensis Kew.................. see’ cE cs ec ee Wie (als Siosge-seesacescccten tasters sotuewes asc eeterens eee eee Sb), SONS 2m ys oe Ostrea, ef. idreaensis Gabb .....0222-222. st eet re, oe Macroeallista conradiana (Gabb).............. Le! tee SES ee ces es. en Mieretrixe orm ‘Galli 2 -----2rree scene cee eases Sykes ee XS Modiolus ornatus (Gabb)......000000..22.. itn t. Ben, 2A ee Tellina remondil Gabb............-.-..:c:s0020c-c+-<<0- itty cite f., ine Sr Ga ee Vienericardia planicosta thiormit (Gralb)p))ece eces eect eee eres eo eee Amauropsis alveata (Conrad)...............--.-- ns x x Nyctilochus whitneyi (Gabb).....................- x Psammobia, ef. hornii (Gabb).........-........- Me Sureula io (Gabb) --...---2.22220 2 cteee eee ye Turris suturalis(?) (Cooper)................-.-.-- BeON (casey ee ee ee Turritella andersoni Dickerson.................. ee te ee ey ee Murritelila, sp cecscesresee eres Turritella uvasana Conrad........00..0..200..-.-- x Mo esa Ke ES TES GE 3503. East side of Loma Alta mountain at head of two large canons extend- ing west from Redrock Canon. 3504. In Oso Creek, just south of the narrows; in muddy sandstone between massive brown shales and bluff white sandstone. 2308. In west branch of Redrock cafion and about three-quarters of a mile northwest of their juncture. 3505. Santa Ynez Mountains in gray shale near steep pitch close to top of the Arroyo Burro trail. 3506. Santa Ynez Mountains on the Ridge trail in saddle west of Arroyo Burro trail. 3507. East side of Oso Creek in second cafion north of mouth. 3508. On west side of Paradise Cafion near its mouth; in dark greenish- gray shales. 3509. In Lewis Cafion immediately above falls; in hard bluish sandstone. 3510. In Oso Cafion about two miles north of mouth; in soft sandstone about 200 feet stratigraphically above bluff light-tan sandstone. North of the river, these shales grade up into fine-grained, thin- bedded sandstone, upon which rests the massive buff to lght-gray 1919] Kew: Geology of a Part of the Santa Ynez River District lal sandstone so characteristic of the Tejon throughout the State. It usually forms bluffs and for this reason this lithologic member is often 7 referred to as the ‘‘bluff sandstone.’’ Its thickness here is about 500 feet. West of Oso Creek the bluff sandstone les in a shallow syncline and forms vertical cliffs equal in height to its thickness. Another feature of the bluff sandstone is its cavernous weathering and nodular appearance. The character of the sandstone is that of a beach sand and for the most part is composed of medium-sized to coarse quartz grains. It is clean, well sorted, and in some places cross-bedded. A thin-bedded, fine-grained, easily weathered, buff to brownish colored sandstone about 1350 feet thick, containing minor amounts of clay shale, overlies the bluff sandstone. The only exposure of this member within the area mapped is located in the axis of the syncline west of Oso Creek, where it has been preserved from erosion. In the Santa Ynez Mountains within the area studied, the Eocene section consists of about 14,000 feet of strata which is far thicker than the section west of Oso Creek. Arnold® measured a section east of Summerland which is over 8700 feet thick, not including the basal beds. The lowest beds exposed in this region are massive hard, brown, well-indurated sandstone, at the base of which is a heavy layer of conglomerate about 150 feet thick, made up mainly of quartzite boulders. This conglomerate is followed by a thin series of soft brown sandstone, which grades up into the green shale similar to that in the Oso Creek section, but harder and of a darker shade. The shale member here as in the latter place is overlain by the massive brownish bluff sandstone which forms the greater part of the Santa Ynez Moun- tains from La Cumbre Peak west to San Mareos Pass and beyond. This section is well shown on the Cold Spring trail and Arroyo Burro trail from Santa Barbara to the Santa Ynez River. The upper soft sandstone is absent from the Santa Ynez Mountains section. As a whole, the Tejon formation corresponds to that given by Eldridge and Arnold? for the Topatopa formation occurring in the range of mountains of that name in Ventura County. The lower part, consisting of about 2000 feet of ‘‘excessively hard, submassive sand- stones and quartzites’’ in the Topatopa Mountains, is not represented by so great a thickness in the Santa Ynez Mountains, but this may be due to the fact that the lower beds are cut out by the Santa Ynez fault. 6 Arnold, Ralph, Geology and oil resources of the Summerland district, Santa Barbara County, California, U. 8. Geol. Surv. Bull. 321, p. 22, 1907. 7 Op. cit. 1; University of California Publications in Geology [ Vou. 12 OLIGOCENE(?) SERIES Sespe Formation Considerable variation in thickness of the Sespe in this district is shown from one locality to another. As a whole, it closely corresponds to the Sespe so well-developed in Ventura County, and to the Pato red member of the Vaqueros described by English® in the Cuyama Valley district. It rests unconformably upon the Tejon group, but is conformable with the Vaqueros formation of the Monterey group, so it is thought probable that in this region no deformative movements took place between deposition of the Sespe formation and the Monterey - group. The Sespe in this district is best represented in the Santa Ynez Mountains, where it occurs in a syneline which extends from the mouth of Paradise Cahon to the Painted Cave east of San Marcos Pass. Another area hes just south of the Santa Ynez River near Mateo Canon, and is separated from the Tejon by the Santa Ynez fault. The formation consists of 1700 feet of fanglomerates, cross- bedded sandstones, and minor amounts of shale and limestone. All the coarse material is rather highly colored, being either red, green, or yellow. In more detail the section here has at its base about forty feet of fanglomerate composed of angular fragments derived mainly from the Franciscan rocks. The greater part of the fragments, composed chiefly of the basic igneous rocks, range in size up to four- teen inches in diameter. Radiolarian chert is also a common material and its fragments are more angular than the others, due probably to their greater hardness. The matrix consists of rather coarse unsorted grains of the greenish basic igneous material. Above this fanglom- erate are cross-bedded sandstones interbedded with softer layers. The sandstone is well sorted, clean, and shows well developed cross-bedding. The colors are also highly variegated, being in some instances purple with light yellow bands, or greenish with yellow or red streaks. Above these varicolored sandstones are softer red and green sandstones within which are a few thin layers of a bluish gray impure limestone. North of the Santa Ynez River, the Sespe is much thinner, and appears to grade into the overlying fossiliferous coarse lower beds of the Vaqueros sandstone. It consists of the usual red fanglomerate 8 English, W. A., Geology and oil prospects of Cuyama Valley, California, U. S. Geol. Surv. Bull. 621, pp. 191-215, 1916. 1919] Kew: Geology of a Part of the Santa Ynez River District 13 beds at the base, followed by other red and green sandstones, for the most part unsorted and slightly conglomeratic. The exposures of the Sespe north of the river are on the hill immediately east of Oso Creek, and on the east slope of Loma Alta. No fossils have been found in the Sespe in the Santa Ynez district, and this fact, together with its lithologic character, strongly suggests that the greater part of the strata accumulated under arid conditions in basins surrounded by steep slopes composed of Franciscan rocks. The marked difference in thickness between the sections of opposite sides of the river may be accounted for in that the surface of deposi- tion was irregular, which did not allow so great an accumulation of detritus in one place as in another. Regarding the age of the Sespe, no definite evidence is obtained from the sections studied in this dis- trict other than that it is post-Tejon and pre-Vaqueros, but it has generally been considered to be Oligocene. MIOCENE SERIES Monterey Group General features.—In the Santa Ynez River district, the Monterey group is made up of four lithologie phases: (1) a lower, rather coarse sandstone containing the Turritella inezana fauna in its lower beds, and the Turritella ocoyana fauna in the upper part; (2) muddy sand- stones, locally nodular, more shaley and enclosing impure limestone lenses; (3) a thin series of cream-colored clay shales containing an abundance of fish scales; (4) an upper zone composed of calcareous and siliceous cherty shales of the type which is so characteristic of the Monterey group over California. The first two are included with the Vaqueros sandstone member of the Monterey group, while the latter two members have been mapped as the Salinas shale® formation of the Same group, a name recently adopted by the U. 8. Geological Survey for these beds in Monterey County. Vaqueros sandstone—Both faunal zones of the Vaqueros, the Tur- ritella inezana and 7’. ocoyana zones are represented, though the former was found only in the west fork of Blue Cafion. At this place, strati- graphic relations have.been obscured by faulting. A fauna, in which Pecten magnolia and Turritella inezana are abundant, is present in 9 English, W. A., Geology and oil prospects of the Salinas Valley—Parkfield area, Cal., U. S. Geol. Surv. Bull. 691-H., 1916. 14 University of California Publications in Geology — [Vou. 12 beds of rather coarse greenish sandstones often conglomeratic, ill sorted, and cemented by a fine muddy sandstone. Where the Vaqueros rests upon the Sespe, as on the east side of Oso Cafion, Loma Alta, and in the vicinity of Mateo Creek, no Turritella inezana fauna was obtained, and the lowest beds contained Turritella ocoyana. More- over, the Vaqueros consisting of coarse brownish sandstone, somewhat conglomeratie in places, grades down into the underlying Sespe with no indication of an unconformity. The usual lithologic section of the Vaqueros consists of a heavy fossiliferous conglomerate at the base, followed by coarse gray to brown massive sandstones, which weather out into prominent strike ridges. This type of sandstone is a characteristic feature of the region on the south side of the Santa Ynez River above the Los Prietos ranger station, and as far east as the Cold Spring trail. Near the top of these sandstones, a twenty-foot bed of impure light gray to nearly white limestone may be traced from east of Blue Canon to Oso Creek. It also forms a prominent feature in the syneline which lies immediately north of the Santa Ynez River in the vicinity of Mono Creek. The following fauna has been obtained from this hme- stone: Cassidulus (Rhynechopygus) ynezanus Kew (Ms.) Cassidulus (Rhynchopygus) ellipticus Kew (Ms.) Seutella, ef. merriami Arnold Pecten, sp. Spiroglyphus, sp. Ostrea, sp. Turritella ocoyana Conrad Terebratalia kennedyi Dall Above the massive sandstones, sandy shales predominate, with inter- bedded layers of nodular muddy sandstones containing a Turritella ocoyana fauna. These shales weather bluish on the surface, but on fresh fractures the color is black, due to their impregnation by petroleum. The main body of these petroliferous shales is located in the Santa Ynez River east of Mateo Canon. Where these strata are not bituminous, the color is usually a light orange or yellow. They are quite soft, and characterized by lenses and nodules of calcareous fine-grained sandstone which contain a Turritella ocoyana fauna. Salinas shale—No sharp line can be drawn between the Salinas shale and the Vaqueros, though the change in rocks is striking. The lower part of the Salinas shale is characterized by white clay 1919] Kew: Geology of a Part of the Santa Ynez River District 15 strata which contain an abundance of fish scales. The shale has the peculiarity of being extremely well bedded, and on weathering breaks up into very thin plates. The upper portion consists mainly of thin rhythmically banded cherty and caleareous beds. A gradual transition from the lower phase takes place, as the cherty type is found interbedded with the clay shales. The calcareous bands in the shale give off a strong fetid odor when struck with a hammer. The best exposures of this section are seen on Little Pine Mountain, Loma Alta, east of Oso Canon, and on the hill immediately behind the ranger station on Mono Creek. At the latter locality the thickness of the Salinas shale is about 600 feet. PLIOCENE SERIES Fernando Formation The Fernando occupies a synelinal basin on the north side of the Santa Ynez River, extending from the large area in the Santa Maria district as far east as Redrock Creek. The great accumulation of deposits representing 3000 feet of shales, sandstones, and conglomer- ates deseribed by Arnold’? from the Santa Maria district is partly represented in the area here described. At Redrock Canon the beds aggregate about 1000 feet, but become thicker to the west. A light gray biogenic shale lying above the Salinas shale probably is the base of the Fernando, since it conforms to the later folding. It closely resembles some of the Salinas shale beds but differs in that it is much softer. Overlying this is a series of fossiliferous sandstones which, in their lower part, are conglomeratic. The pebbles in the conglomerate have been derived almost entirely from the chert of the Salinas shale. Above this, a softer tan and gray sandstone contain- ing Dendraster ashleyi var. inezanus Kew (Ms.), grades up into a hard gray sandstone containing this same echinoid and also Nassa califor- nica Conrad. In the small syneline within the main synclinal trough, beds of continental origin are found. These consist of reddish, buff colored muds and sands interbedded with layers of unsorted conglom- erate. Teeth and limb bones of rodents were obtained from the clays and sands of these beds. Farther to the west, these deposits become thicker and more extensive. Their lithologic nature, together with the 10 Arnold, Ralph, Geology and oil resources of the Santa Maria oil district, Santa Barbara County, California, U. 8. Geol. Surv. Bull. 322, 1907. 16 University of California Publications in Geology [ Vou. 12 fact that they rest upon beds of upper Fernando age, suggests that they may be correlated with the Paso Robles formation, which is well developed in the Salinas Valley. Arnold'™ mentions similar land-laid deposits from the Santa Maria district and says that they are probably the equivalent of the Paso Robles formation. None of the beds in this district are of Miocene age, and the faunal evidence indicates that they are upper Pliocene and do not represent the lower Fernando occurring in the Elsmere Canon section of the Santa Clara Valley. QUATERNARY SYSTEM TERRACE DEPposits At least six distinct deposits of terrace material are present along the Santa Ynez River, the highest one being at an elevation of 1500 feet. Their extent is not large enough to show on the map and the deposits forming any one terrace are never over 100 feet thick. They are composed of unsorted material, usually unconsolidated, which has been washed down from the higher areas at their rear. Where made up of the diatomaceous shale, the material is much finer than when derived from the hard Tejon or Cretaceous rocks, and huge boulders several feet in diameter are a common occurrence in the beds that are well exposed in the vicinity of Mateo Potrero. STRUCTURE GENERAL FEATURES The structure of the California Coast Ranges is relatively complex, but in general, the folding and faulting has a definite northwest trend which is reflected topographically. In the Santa Ynez River district, the San Rafael Mountains conform to this general habit, whereas the Santa Ynez Mountains are anomalous in that their trend is almost east-west. The general structure of the latter range is that of an anticline, dislocated on the north side by the Santa Ynez fault, the faulting having occurred in post-Fernando time. In the vicinity of San Marcos Pass, the fold is comparatively simple, whereas on the south side of the range, east of La Cumbre Peak, the strata are over- turned to the south. Another set of folds within the range has a northwest strike, and probably was formed prior to the general anticlinal folding of the mountains but at the same time as the 11 Arnold, Ralph, Geology and oil resources of the Santa Maria oil district, Santa Barbara County, California, U. 8. Geol. Surv. Bull. 322, p. 55, 1907. = tity 4 7 Mak re i ar ; i \ , SF JOV {WIX4 vm te Mh & ae aaaeieie yeomn * | Wi i Cr Anas : 7 rad , me Ie, ry Piceagel Miers Pes : = Wd ara Ls ; wOe———~ F ie } roar p wet oh soe’ ee b. wah ORT ee Heri Ns 4 sex | me ‘ i rary ee bye 1 Nea AR PEI Sericmemettocinie etic chr ned ch and iy emma ppl aman NB Na } z oo {Re —- H ie ty t 7 ~ Vy ais hey rc wy | y ee ~ I nae t a ima! ‘4 =. 420% “3 , ’ y ‘ » 5 ~~) | : H i tye Pee tee - nl 5 faethe by K i ey WY tes Ha MAL eng Stt mae EE, | HED , ‘ ; t Pr Ree A Bo Oi oh dkiave ¢ Qo ks Te aaeiod onal hier j ‘ hy . : ats - i} , a UNIV. CALIF, PUBL. BULL. DEPT. GEOL. [KEW] VOL. 12, PL. 2 Tj Tf Tms Tmy Je Sealevel B’ Tms Tmv Jf ty TsTmvTj Jt Kse Tmy = Tms Tmy Tms Sealevel C’ Ts uw) Ts Tmy Jt Ke ——2000 1000 Sealevel D’ Ts Tj Ts Tmy Kse JE Ksc Tmy Ksc SrRvucTuRE SECTIONS IN SanTA YNEZ RiveR DisTRICT, CALIFORNIA For lines of sections see Plate 1 EXPLANATION.—Tf, Fernando formation; 7’ms, Salinas shale; Tmv, Vaqueros sandstone; 7s, Sespe formation; 7j, Tejon group; Ksc, Shasta and Chico rocks; Jf, Franciscan series, 5 hed ri Te aa en i ee a i * q Win. BE. RAS ~~ } ; way. «7 TE Come site 7 care dea ow nt an re ner tye enna ecee Ser om eaeree S | i 2 : : ft sae, ae n at Plast = wins met tins Me } { \ t inn o¥ acne nen mega mre aati e ee AAS EL RODE, BH VIR £ oislE av2 aucitues to aol wt (sSaR: Pie :attecrnd eigen lt AT. na Adee 2 aah query soph. ° stonaarwk aqase et removal irse ; array seogice”t AS 1919] Kew: Geology of a Part of the Santa Ynez River District 17 deformation of the San Rafael Mountains. Although only a small part of the San Rafael Mountains was examined, the Little Pine Mountain vicinity indicates a northeastward dipping series of rocks ranging in age from Jurassic(?) to the end of the Miocene. These are faulted on the south side by the Little Pine fault which is of pre-Fernando age. In the area between these two faults is a belt of acutely folded rocks, in greater part of Miocene age, though Franciscan and Tejon strata appear between Oso and Redrock creeks. These three areas constitute separate structural belts which will be described more in detail. Three large faults cut this district in an east-west direction, the longest being the Santa Ynez fault, which follows the north side of the Santa Ynez Range and has evidently controlled the corrasion of the river. The Redrock fault is comparatively short, but has brought the Franciscan rocks up against the beds of the Monterey group. North of this fault, the Little Pine fault extends along the foot of Little Pine Mountain and continues to the east, following the Santa Ynez River Canon to Blue Canon. The age of the first is post-Plocene, while the latter two are pre-Plocene. Several cross faults are present in this region, which will be discussed in the section on detailed structure. DETAILED STRUCTURE LitTtLeE Prine Mountain AREA This area includes all the territory lying north of the Little Pine fault and extending east to Agua Caliente Creek. Little Pine Moun- tain is composed of a block of northward dipping Franciscan and Cretaceous strata overlain by beds belonging to the Monterey group. The structure of the Franciscan series is complex and obscure, due to the great amount of deformation chiefly caused by the large in- trusions of igneous rocks. In general the sandstones and cherts strike in a northwesterly direction, and the igneous rocks are intruded along their bedding planes. The Cretaceous dips on the average about forty degrees to the north, except in the eastern part of the area, where the strata have been so acutely folded that the structure is obscure. Lying upon the Cretaceous are two relatively small synclinal areas of Miocene rocks. The eastern one lies directly north of the Santa Ynez River and crosses Mono Creek at the ranger’s cabin. The Monterey group is here considerably less folded than the underlying Cretaceous sandstones and shales, and the syncline pitches east about five degrees and gradually broadens. Near the junction of Blue Canon with the 18 University of Califorma Publications in Geology — [Vou. 12 Santa Ynez River the fold is cut by a cross fault, beyond which it is materially narrowed, though the syneline can be traced considerably farther to the east. The other syncline forms the top of Little Pine Mountain. It is quite shallow, as the Salinas shale les nearly flat at the summit. The northward extent of these rocks has not been traced. The most important structure related to this area is the Little Pine fault, which hmits it on the south. The fault is remarkably straight and topography characteristic of faulting is common along it. The trace of the fault is usually distinct as it separates the soft Tejon shales from the Franciscan in some places, and in others, the Knox- ville shales from the Monterey group, being thus a noticeable feature in the topography of the country. The altered serpentine in which the cinnabar occurs is present only on this fault zone. The rock is somewhat harder than the adjacent strata, and it weathers into a rather prominent ‘‘reef’’ along the fault. The dip of the fault plane is nearly vertical, though a dip of eighty degrees to the south was noticed in a few places. A minor cross fault dislocates this main fracture in the canon north of the big bend in the Santa Ynez River. To the west of Redrock Creek, the fault is overlapped by the Fer- nando strata, thus placing its age as pre-Fernando. In its eastward extension, it is cut off by a cross fault at the mouth of Blue Cajon. At this point it is quite close to the Santa Ynez fault, the two being about a mile apart. This indicates that structural lines of both the San Rafael and Sana Ynez mountains are convergent in this region. Santa YNEZ River AREA The most highly folded Tertiary strata in this district lhe within the belt of formations that trends in a northwest direction along the course of the Santa Ynez River. It is about a mile wide at its eastern end, where it is cut off by a cross fault near the mouth of Blue Canon; to the west it broadens until, at Loma Alta, the width is somewhat more than five miles. Complicated folding and faulting are a characteristic of the area. The most interesting piece of struc- ture is that of Loma Alta and the adjacent region to the east, includ- ing the high hill east of Oso Creek. Loma Alta is made up of a series of strata ranging in age from the Tejon through the Monterey group, the oldest of which rest upon the Franciscan series. The essential structure is anticlinal, broken by the Redrock fault along the eastern end of its axis. Although the beds are fractured close to the main ridge of Loma Alta, the fault does not pass through the moun- 1919] Kew: Geology of a Part of the Santa Ynez River District 19 tain. The shales and cherts of the Monterey group forming this part of Loma Alta have a comparatively simple attitude, dipping to the west and forming the nose of a steeply pitching anticline. To the east of this main ridge, erosion has produced a cirque-like excavation which has exposed the underlying rocks of the Franciscan and Tejon series that form the north limb of the anticline in Redrock Canon. The south flank of the fold has been faulted down, so that the strata of the Monterey group have been thrown against the Franciscan. The Monterey beds dip to the west with a north strike near the summit of Loma Alta and then swing to the southeast and east, forming a strike ridge on the south side of the mountain. The beds near Red- rock Creek become steeply tilted until they are slightly overturned in the bottom of Redrock Canon. All the lower part of the Monterey, including the heavy bedded sandstones, has been faulted out, leaving only a thin strip of the finer grained upper members. In contrast to the steeply tilted beds of the south side, the north limb of this anticline is made up of comparatively gently dipping Tejon strata resting unconformably upon the Franciscan rocks. On Loma Alta Mountain, the Tejon is overlain by the Sespe formation and Monterey group. The whole series is terminated on the north by the Little Pine fault, which cuts across these beds in some places at right angles to their strike. The more elevated region between Oso and Redrock creeks and that east of Oso Canon is occupied by an eastward pitching syneline, which is the complementary fold to the Loma Alta anticline described above. Both the Eocene and Miocene rocks are involved in the fold- ing, the latter being represented only east of Oso Creek. The massive bluff sandstone of the Tejon stands out prominently west of Oso Creek as a shallow trough which forms eliffs about five hundred feet high along its margin. The Little Pine fault on the north side cuts obliquely the different members of the series so that only a small part of the bluff sandstone, considerably broken, remains at Oso Cafion. Although the axis of the syncline is not traversed by the Little Pine fault, nevertheless faulting has taken place along it, so that the steeply tilted and broken remnant of the north limb les against the gently dipping southern part of the Tejon and Miocene strata. The bluff sandstones as exposed here were continuous at one time with the same member of the Tejon which is present on the west side of Red- rock Canon. Along the Santa Ynez River itself, the structures are more com- plex than in any other part of the district. South of Loma Alta, the 20 University of California Publications in Geology [ Vou. 12 Fernando has been faulted down against the Salinas shale and folded into a synecline and anticline. These folds are closely com- pressed in Redrock Canon, but flatten out to the west so that the dip of the beds is not over twenty degrees. East of Redrock Cafion com- plexly contorted and faulted strata prevail. The Monterey group extending east from the Loma Alta area is usually overturned and complicated by numerous small faults. The Redrock fault east of Loma Alta ends at a cross fault, which occurs just west of the big bend in the Santa Ynez River. East of this bend the strata show more definite structure; also a more continuous section from the Sespe through a greater part of the Monterey is exposed. Two folds, a synchne and an anticline which pitch to the west may be traced as far east as the Cold Spring trail. The Santa Ynez fault which forms the southern limit for this area is of especial interest in that it represents one of the latest periods of disturbance in this region. This fault traverses the entire width of the Santa Ynez district in a direction slightly south of east and is approximately parallel with the axis of the Santa Ynez Range. It separates the Eocene strata forming the major part of the mountains from the Miocene and Phocene rocks on the north. Evidence as to the dip of the fault plane is not usually available, but, wherever seen, the dip is approximately vertical. The fault trace is marked by straight canons and saddles in ridges. ‘This is strikingly shown in Blue Canon and on the divide at the head of its west branch. The fault is by far the largest in the district and probably extends farther to the east up Blue Cafion, though it has not been followed beyond the limits of this district. SANTA YNEZ MouNTANS AREA The Santa Ynez Mountains are characterized by two sets of fold- ing which probably occurred at different periods. The earlier set is represented by the northwesterly striking folds immediately east of San Marcos Pass. The largest of these is a syncline whose axis follows closely the trend of Paradise Canton. Infolded with the Tejon rocks is about 1700 feet of the Sespe formation. To the west of this fold an anticline and syncline parallel this fold on the west. They are considerably shallower, so that the Sespe formation has been eroded from the syncline. All these folds are cut off obliquely at the north by the Santa Ynez fault. 1919] Kew: Geology of a Part of the Santa Ynez River District 21 The folding of the later period is shown in the main structure of the mountains, namely, the Santa Ynez anticline. This deformative movement has continued to comparatively recent times, for late Pliocene strata of marine origin along the beach at Santa Barbara have been tilted to an angle of forty-five degrees and raised considerably above sea level. The axis of the fold extends approximately along the erest of the range, but east of the San Marcos Pass it swings slightly northward, and passing to the north of La Cumbre Peak is terminated by the Santa Ynez fault. To the east of La Cumbre in this district the north limb of the anticline has been faulted out, and the Miocene beds have been let down against the Tejon along the axis of the fold. Near San Marcos Pass, the fold is broad, the gently dipping massive sand- stones forming the slopes of the mountain in this vicinity. Farther to the east, the strata become tilted to a much greater angle, and east of La Cumbre Peak the major part of the beds constituting the south limb of the anticline is overturned. The foothills of the range are made up of post-Eocene formations resting upon the Tejon. Arnold’ has described the geology and structure of the mountains in the vicinity of Summerland, which is similar to that in the western part of the district. CONCLUSIONS Although the stratigraphy of the Santa Ynez district is similar to that usually occurring throughout the California Coast Ranges, a few observations of interest should be emphasized. (1) The Sespe forma- tion and Monterey group in the Santa Ynez district were laid down without the interruption of deformative movements, during which time the sea transgressed upon the land; (2) at least two periods of folding and faulting have taken place since the Miocene: the first before the deposition of the Fernando formation, the second after the Fernando and probably continuing into Recent time; (3) the Santa Ynez Moun- tains are genetically as well as geographically distinct from the San Rafael Mountains, the former having been formed during the later diastrophic movements (post-Plocene), and the latter during the earlier ones (pre-Pliocene), in which the forces acted in a different direction. Transmitted April 23, 1919. 12 Arnold, Ralph, Geology and oil resources of the Summerland distriet, Cali- fornia, U. S. Geol. Surv. Bull. 321. ates 3-42 5 text figures ‘ September 28, 1920 — TACEOUS AND CENOZOIC ECHINOIDEA OF THE PACIFIC COAST OF oe eS NORTH AMERICA... = re BY WILLIAM S. W. KEW bp Suthsonlan Instltuiig~ -¢ NOV 5 1999 } S f - ~SHonal Muse? ; UNIVERSITY OF CALIFORNIA PRESS BERKELEY & UNIVERSITY OF CALIFORNIA PUBLICATIONS WILLIAM WESLEY & SONS, LONDON. Agent for the series in American Archaeology and Ethnology, Botany, Geology, Physiology, and Zoology. {Pia Geology. ANprEw C. LAwson and JouNn C. Merriam, Editors. Price, volumes 1-7, $3.50,” fe volumes 8 and following, $5.00. Wolumes 1-11 completed; volume 12 in progress. zt: Cited as Univ. Calif. Publ. Bull. Dept. 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Pseudostratificatidn in Santa Barbara County, California, by George Davis Louder- Dee nae or Aisa neonate ckpnp inn pedatbnncectapnanes ccsccecbevonnt toctuaeees SpE e REESE oe ae 20¢ 3. Recent Discoveries of Carnivora in the Pleistocene of Rancho La Brea, by John C. ; Mier ria mi, 00 ci! sos os ecdon lo dso laze wood TS ae JLo 5e : 4. The Neocene Section at Kirker Pass on the North Side of Mount Diablo, by Bruce Gare eae seb cae t ce cnn semen eesercncbes otanacbielsss nuapeezateceSuae Pueatenieten Sten: Sua iee een eatn ee eee eae 15¢ 5. Contributions to Avian Palaeontology from the Pacific Coast of North America, by oye Holmes Miller 2c002 24 ote aet ln aot be a econ been tn tea ee ocen sce gse eee ee '60e 6. Physiography and Structure of the Western EH] Paso Range and the Southern Sierra Nevada, by Charles Laurence Baker) «1.......22.2.si.-ccsecccecsoece decode soeseteentiresbedue ee 30¢ 7. Fauna from the Type Locality of the Monterey Series in California, by Bruce Martin. 10¢ 8. Pleistocene Rodents of California, by Louise Kellogg... ..--eeseecenc-sececeneneeenenens 15¢ 9. Tapir Remains from Late Cenozoic Beds of the Pacifie Coast Region, by John C,_ AMI TYE as 2c ee apace dune Occurs in strata equivalent to Gatun formation of Gulf Coastal Plain. Hotei) 210 i OUP URLS Te OT Oat 2 f tae - ey ae ravine = a “4 ! eat VY lt iss * : ta . niaweOsemlIne QOe ; Ba ehvvoge RPh oe (WOE) Atte treat ‘egivord at : sfaenQa& stuopoly Sipe { X15 fra : se SiS, 39% EL ENE tiie - 7 walk ieee 4 retsqarel ; By re ed OEE ohh ree e {4 soviet yess neem, HUEthel iihoru 2) Thies fs ilgdogiw't eienommltlaos (2) ci habee ieee Jotitiaiebe. a eieiel sedommt akan ate eae {odotin? thezeiiwk att ate é depecaes coy OU BLS MCRL ‘altetisel ihe sy Atertiandh- li r = ke eee td - itonst pedro Baad oy ce ; 2 SRE Bie soy dtaudick sb Reows. _ low. aa an oa senna me TO ( Trportxs say z diay RIES ie toe a PEE. at L Bios 9 DT Ry wileaeoe ; ee oe ero fia k | fargityouit ailatioe ‘= i : : = Woe 5: sdaiooriaa pee Lisi) V/s 9 anak ion panei one aa er ee RR en Set cs See et pr. Woah airs sodpay iP: ‘ se 8 aia \icogh eke =, Cae enmaeneene (toe) = ee eer EOE LER ee TS anesstgah ihe ie . ae work + eea619 Thh - « 5 =ee- —s~ moo 1920] Kew: Cretaceous and Cenozoic Echinoidea 53 Locality—Holotype from Santa Cruz quadrangle, Santa Cruz County, locality 109, on Bear Creek, four miles above its confluence with the San Lorenzo River, California. CIDARIS MARTINEZENSIS Kew, n. sp. Plate 3, figures 2a, 2b, 2c Cidaris (?) sp. c. Dickerson, Univ. Calif. Publ., Bull. Dept. Geol., vol. 8, 1914, p. 121, pl. 6. Figured specimen.—No. 11400 Univ. Calf. Coll. Invert. Pal. Test of small size. Measurements of specimen no. 11400: greatest diameter 11.8 mm., greatest height 5.2 mm. Upper surface somewhat flattened, lower surface concave to the peristome. Peristome very large. Ambulacra rather broad. Interambulacra bearing two rows of large primary tubercles whose areolas closely approach each other ; outer areas marked by a ring of granules. The casts of spines of this species are long, measuring at least 10 mm. in length. Geologic horizon.—Martinez group, Lower Eocene. Locality—Swett’s ranch, Contra Costa County, California. CIDARIS MERRIAMI Arnold Plate 3, figure 3 Cidaris merriami Arnold. Proe. U. 8. Nat. Mus., vol. 34, 1908, p. 359, pl. 32, fig. 8. Cidaris merriami. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 696. Cidaris merriami. Clark and Twitchell, U. 8. Geol. Surv. Mon., vol. 54, 1915, pp. 114-115, pl. 55, fig. 4. Cidaris sp. (d) Dickerson. Univ. Calif. Publ., Bull. Dept. Geol., vol. 8, 1914, p. 121, pl. 6, figs. 6a—6b. Holotype.—No. 165438 U. 8S. Nat Mus. Inasmuch as no further characters were obtainable from the specimen at hand, Arnold’s original description will be given: The test of this species is unknown, but the abundance and well-marked characteristics of the fragments of the spines has been deemed of enough importance to justify a specific name. Seven specimens have been obtained at the type locality, each showing the characters described above. Spines subcircular in cross section, as much as 4 millimeters in diameter and probably over 40 millimeters in length, tapering very slightly; surface sculptured by 13 or 14 prominent, narrow, nodose, ridge-like, longitudinal ribs separated by narrow, deeply incised grooves; the nodes are well defined, especially in the younger stages of growth, and are subelliptical in cross section, their longer axis being parallel with the axis of the spine. 54 University of California Publications in Geology [Vou. 12 H. L. Clark, who examined the specimens for Arnold, says: All appear to belong to one species, except possibly one fragment. “hat piece might possibly have come from quite a different species. I am very glad to see this material of merriami, for it satisfies me that the species must have been allied to, if not identical with, Tetrocidaris perplexa Clark (Cidaridae, p- 205, pl. 6, figs. 1, 2; pl. 7, figs. 1-4, 1907), the only other living littoral cidarid known from north of Panama (other, I mean, than thouarsii). So your material shows that the ancestors of both thouarsvi and perplexa lived in the Tertiary in California. Geologic horizon.—Martinez group, Lower Eocene. Localities —Holotype from Santa Cruz quadrangle, San Mateo County, locality 25; ridge between head-waters of San Lorenzo River and Peseadero Creek, California. Specimen, no. 11401 Univ. Calif. Coll. Invert. Pal., from north side of Mount Diablo, Contra Costa County, California. CIDARIS TEHAMAENSIS Clark Plate 3, figure 1 Cidaris tehamaensis Clark. U.S. Geol. Surv. Mon., vol. 54, 1915, p. 44, ploy hen: Holotype.—No. 31195 U.S. Nat. Mus. The writer has had no opportunity to study a specimen of this species, and for this reason the description of Clark will be given verbatim : This species is represented by a well-preserved spine that is large and club- shaped. The granules are large and disposed in rows extending from the neck to the point of the spine. Geologic horizon.—Knoxville formation, Lower Cretaceous. Locality —Shelton’s ranch, Tehama County, California. CIDARIS THOUARSII (?) Valenciennes Cidaris thouarsii Valenciennes. Agassiz and Desor, Catalogue raisonné des échinodermes, Ann. des sci. nat., vol. 6, 1846, p. 326. Cidaris sp. a Arnold. Proc. U. 8. Nat. Mus., vol. 34, 1908, pp. 351, 359. Cidaris sp. a. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 701. Cidaris thouarsii (?). Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 1915, p. 179. Specimen in U. 8. Nat. Mus. Coll. 1920] Kew: Cretaceous and Cenozoic Echinoidea 55 Inasmuch as no material has been available for study the descrip- tion used by Twitchell is given: This species, which Arnold has referred to under the name Cidaris sp. a, is regarded by H. L. Clark as probably C. thouarsii. He says in a letter quoted by Arnold: The wax cast (Cidaris sp. a) is a spine of a true cidaris and very much like many spines of some individuals of the species of Cidaris common on the west coast of Lower California, Mexico and Central America, C. thouarsit. I do not think it shows a single feature by which it can be distinguished from thouarsii; it is certainly from the ancestor of that species. Geologic horizon—Monterey shale, Middle Miocene. Locality —Santa Cruz quadrangle, California. CIDARIS sp. a Dickerson Cidaris sp. a Dickerson. Univ. Calif. Publ., Bull. Dept. Geol., vol. 8, 1914, p. 121, pl. 6, figs. 4a, 4b. Cotypes—Nos. 11729 and 11853 Univ. Calif. Coll. Invert. Pal. Dickerson’s description is as follows: Test unknown. Spines long, very slender, circular in cross section. Certain incomplete specimens are 15 mm. long and only 1 mm. in diameter with only a slight taper. Surface of spine marked by microscopic longitudinal lines or ribs. The distal end is marked by a small ball which is decorated by about fourteen strong rounded ribs. This ball terminates in a rounded tip. The base is marked by a well-developed collar and a rounded socket in its end. The base does not appear to be ornamented. The surface of the rock is covered with spines which have been weathered out. The description is based upon several fragments of spines. Geologic horizon.—Martinez group, Lower Eocene. Localities—Mount Diablo region, Univ. Calif. loes. 245 and 1556. CIDARIS indet. sp. Cidaris sp. Kew, Univ. Calif. Publ., Bull. Dept. Geol., vol. 8, 1914, p. 51. Genital plates pentagonal, with rounded sides. Genital pores large. Abactinal surface has a single row of primary tubercles at both mar- gins of the interambulacral area. Interporiferous area contains a double row of primaries. Below the ambitus tubercles sporadically placed. Ambulacral area about one-third that of the interambulacral area. Ambulacral pores arranged in straight radial rows. Spines cylindrical, elongate, and granulated, the granulation being arranged in vertical rows. Internal structure of the spines consists of rows of mesh-like cells radiating from a central point. Specimen.—No. 12361 Univ. Calif. Coll. Invert. Pal. 56 University of California Publications in Geology [Vou. 12 The description of the test is taken from an imperfect young specimen. Geologic horizon.—Lower Division of Carrizo Creek beds, Pliocene. Locality—Coyote Mountain, Imperial County, California, Univ. Calif. loc. 738. OrDER CENTRECHINOIDA Jackson SuporperR CAMARODONTA Jackson Famity ECHINIDAE Agassiz Genus TRIPNEUSTES Agassiz TRIPNEUSTES (HIPPONOE) CALIFORNICUS (Kew) Plate 3, figure 5 Hipponoé californica Kew. Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, 1914, pp. 50-51, pl. 1, fig. °2. Hipponoé californica. Clark and Twitchell, U. 8. Geol. Surv. Mon., vol. 54, 1915, p. 111. Holotype.—No. 10055 Univ. Calif. Coll. Invert. Pal. Size of test large. Measurements of specimen no. 10055: trans- verse diameter approximately 85 mm., greatest thickness approxi- mately 75 mm. Thin and conical in shape, with the ambitus situated near the base. Actinal surface somewhat concave. Ambulacra broad, with the poriferous area equal to the non-poriferous area. Poriferous zones consisting of three pairs of conjugate pores arranged obliquely and placed one above the other, forming radial lines. Middle pair sporadic. Furrows joining pores become very marked below ambitus. Tubereles on ambulacra irregularly placed on both poriferous and non-poriferous plates. Interambulacral area twice as wide as the ambulacral area. Five primary tubercles on each interambulacral plate near the ambitus and arranged in radial rows. The number of tubercles becomes less toward the apical system. Related forms—The Recent Hipponoé depressa A. Agassiz found in the Gulf of California and on the west coast of Lower California is closely allied to Tripneustes californicus. The latter has fewer tubercles than the former; also the ambitus is situated lower down, giving it a more distinctly conical shape. Geologic horizon——Lower Division of the Carrizo Creek beds, Pliocene. Locality—Coyote Mountain, Imperial County, California, Univ. Calif. loc. 2064. 1920] Kew: Cretaceous and Cenozoic Echinoidea BY Famiry STRONGYLOCENTROTIDAE Gregory Genus STRONGYLOCENTROTUS Brandt STRONGYLOCENTROTUS FRANCISCANUS A. Agassiz Plate 4, figures la, 1b, le Toxocidaris franciscana A. Agassiz. Bull. Mus. Comp. Zool., vol. 1, 1863, p. 22. Toxocidaris globosa A. Agassiz. Proc. Acad. Nat. Sei. Phila., vol. 15, 1863, p. 356. Strongylocentrotus franciscanus A. Agassiz. Rev. Ech., Ill. Cat. Mus. Comp. Zool., pt. 1, 1872, p. 163; pt. 3, 1872, p. 442, pl. 5b, figs. 1-2, pl. 7, figs. 10, 10a. Strongylocentrotus franciscanus. Arnold, Calif. Acad. Sci. Mem., vol. 3, 1903, p. 90. Strongylocentrotus franciscanus. Stefanini, Boll. Soe. geol. ital., vol. 30, 1911, p. 706. Strongylocentrotus franciscanus. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 1915, p. 223. Figured specimen.—No. 11389 Univ. Calif. Coll. Invert. Pal. This specimen is of rather small size. Measurements: greatest diameter 38.7 mm., greatest thickness 16 mm. Two main vertical rows of large tubercles in the interambulacral areas which occupy the greater part of the plate; two short rows of smaller tubercles near the median line, and a row along the border of this area; other smaller secondaries are present. Ambulacral areas contain two rows of pri- maries, smaller in size than those of the interambulacral areas; a median row between the primaries and a row of secondaries in each poriferous area are present. Ares of pores oblique and contain as many as nine pairs. Both upper and lower surfaces considerably flattened. Arnold, in discussing its occurrence on the Pacific Coast, says: This is the large sea urchin of the west coast. Spines which are probably of this species have been found in the lower San Pedro series of Deadman Island. The spines of this species are distinguishable by their large size and longitudinal striations. Some of the spines are 20 millimeters long and 3 millimeters in diameter. Geologic horizon.—Upper Fernando formation, Upper Pliocene; associated with Dendraster diegoensis subsp. venturaensis Kew. San Pedro formation (lower part), Pleistocene ; Recent. Localities—Las Posas Hills, Ventura County, California, fig- ured specimen; San Pedro, Los Angeles County, California; Fourth and Hill streets, Los Angeles, California (Moody). 58 University of California Publications in Geology [Vou.12 STRONGYLOCENTROTUS PURPURATUS (Stimpson) Echinus purpuratus Stimpson. Crust. Echin. Pac. Coast, 1857, p. 86. Strongylocentrotus purpuratus. A. Agassiz, Rev. Hch., Il. Cat. Mus. Comp. Zool., pt. 1, 1872, p. 165; pt. 3, p. 449, pl. 5a, figs. 5-6, p. 16, fig. 7, pl. 36, fig. 9. Strongylocentrotus purpuratus. Arnold, Calif. Acad. Sci. Mem., vol. 3, 1903, pp. 90, 91. Strongylocentrotus purpuratus. Stefanini, Boll. Soc. geol. ital., vol. 30, OT pe OM Stronaylocentrotus purpuratus. Clark and Twitchell, U. 8. Geol. Surv. Mon., vol. 54, 1915, p. 223. The occurrence of spines of this form is rather common in the Upper Pliocene and the Pleistocene formations of the west coast. Arnold discusses their occurrence as follows: Numerous spines of this small purple sea urchin have been found in the San Pedro series. No part of the test has ever been discovered in these deposits, to the writer’s knowledge. Several nearly perfect tests of this species were found in the Pleistocene (lower San Pedro series) deposits at the bath house, Santa Barbara. A nearly perfect test was also found in the upper horizon of the San Diego formation (Pleistocene (?) at Pacific Beach, near San Diego. Geologic horizon—Upper Fernando, San Diego, and San Pedro formations, Upper Phocene, Pleistocene, and Recent. Localities —Paeifie Beach, San Diego County; Fourth and Hill streets, Los Angeles (Moody); San Pedro and Santa Barbara, Cal- fornia (Arnold). OrpdER EXOCYCLOIDA Jackson SuBoRDER CLYPEASTRINA Gregory Famity CLYPEASTRIDAE Agassiz Genus CLYPEASTER Lamarck CLYPEASTER BOWERSI Weaver Plate 5, figures la, 1b; plate 6, figure 1 Clypeaster bowersi Weaver. Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, 1908, pp. 271-272, pl. 21, fig. 1, pl. 22, fig. 1. Clypeaster bowersi. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 701. Clypeaster bowersi. Kew, Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, 1914, pp. 50-51, pl. 3, figs. la-1b, and pl. 4, fig. 1. Clypeaster bowersi. Clark and Twitchell, U. S. Geol. Survey Mon., vol. 54, 1915, p. 209, pl. 96, figs. la-b. 1920] Kew: Cretaceous and Cenozoic Echinoidea 59 Cotypes.—Nos. 10059 and 10060 Univ. Calif. Coll. Invert. Pal. Outline suboval to pentagonal. Test thick and very large. Meas- urements of average sized specimen, no. 10060 Univ. Calif. Coll. Invert. Pal.: anteroposterior diameter 133 mm., transverse diameter 113.7 mm., greatest thickness 41 mm. Profile rounded to subtriangular. Edges of test swollen in some specimens. Margin slightly reéntrant opposite the interambulacral areas. Petals broad, obovate, and nearly closed at their extremities. Poriferous areas narrow and slightly sunken. Interporiferous areas of petals somewhat raised. Two lateral petals of the trivium shorter than the other petals. Odd anterior petal nar- rower than the others. Pores conjugate. Apical system central and small. Actinal surface nearly flat, with peristome deeply sunken. Anus large, depressed, and located immediately below the margin of the test. Ambulacral furrows narrow, deep, and extending from the mouth to the edge of the test. Tuberecles small, crowded, and uniform in size over the whole test. Related forms.—Clypeaster bowerst Weaver resembles very closely Echinanthus (Clypeaster?) testudinarius Gray living in the Gulf of California. The average size of Clypeaster bowersi is larger and it has a slightly more elevated test than Echinanthus testudinarius. The anus of the former is situated at the edge of the test while that of the latter is situated away from the margin a distance equal to its own diameter. Geologic horizon—Lower Division of the Carrizo Creek beds, Pliocene. Locality—Coyote Mountain, Imperial County, California, Univ. Calif. loc. 2064. CLYPEASTER CARRIZOENSIS Kew Plate 7, figures 2a, 2b Clypeaster carrizoensis Kew. Univ. Calif. Publ. Bull. Dept. Geol., vol. 8. 1914, p. 49, pl. 2, figs. 2a-2b. Holotype.—No. 10047 Univ. Calif. Coll. Invert. Pal. Test small. Measurements: maximum anteroposterior diameter 24 mm., maximum transverse diameter 21 mm., maximum height 7 mm. Outline pentagonal to suboval, with slight notch opposite the inter- ambulacral areas. Test depressed, thick, and edge slightly swollen. Apical system central, elevated but little. Petals tumid and wide open at the ends, extending over one-half the distance to the margin. Interporiferous spaces slightly raised, but pores sunken, especially the 60 University of California Publications in Geology [Vou 12 outer row, the inner row being situated on the slope of the raised area of the petal. Pores conjugate. Actinal surface deeply sunken to the peristome. Ambulacral furrows broad, deep, and extending undivided to the edge of the test. Anus inframarginal. Tubercles small and of uniform size on both actinal and abactinal surfaces. Related forms.—This species is not related to any living form in the Gulf of California. It resembles slightly Scutella gabbi (Rémond) from the San Pablo formation of middle California. The shape of Clypeaster carrizoensis is more nearly pentagonal, the edges of the test thicker, and the apical system more nearly central than in Scutella gabbi. Geologic horizon—Lower Division of the Carrizo Creek beds, Phocene. Locality.—Coyote Mountain, Imperial County, California. Holo- type from Univ. Calif. loc. 738. CLYPEASTER DESERTI Kew Plate 7, figures la, 1b Clypeaster deserti Kew. Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, 1915, p. 48, pl. 3. Holotype.—No. 10056 Uniy. Calif. Coll. Invert. Pal. Test large. Average measurements: anteroposterior diameter 80.3 mm., transverse diameter 78 mm., greatest thickness 10.6 mm. Pen- tagonal to subcireular in outline. Margins broadly notched opposite the interambulacral areas, the two lateral posterior notches being larger and the median posterior notch smaller than the anterior ones. Test not markedly thick, but margin swollen except opposite the posterior interambulacral area. Apical system central and raised. Petals short, very tumid, reaching about half the distance to the edge of the test and tending to close at their ends, those of the trivium to a greater degree than those of the bivium. Anterior petal longer than the other four, which are of approximately the same length. Poriferous areas broad, and pores conjugate. Tubercles small and of the same size on both sides. Actinal surface flat, with mouth central and slightly sunken. Anus large and inframarginal. Internal structure made up of concentric rows of slender pillars near the edge of the test. Related forms.—This species may be distinguished from the Recent Clypeaster rotundus A. Agassiz of the Gulf of California, by its more 1920] Kew: Cretaceous and Cenozoic Echinoidea 61 nearly pentagonal shape and thinner margin. In C. desert: the odd anterior petal is the longest, and slightly open, the remainder being of the same length. The longest petals in C. rotundus are the bivium, and these are nearly closed. Geologic horizon——Lower Division of the Carrizo Creek beds, Phocene. Localitics —Coyote Mountain and Carrizo Valley, Imperial County, California. Type from Univ. Calif. loe. 2064. Famity FIBULARIIDAE Gray Genus SISMONDIA Desor SISMONDIA (?) ARNOLDI Twitchell Plate 4, figures 2a, 2b Astrodapsis sp. indet. Arnold. U.S. Geol. Surv. Bull. no. 396, 1909, p. 30, pl. 28, figs. 5-5a. Astrodapsis sp. indet. Arnold and Anderson, U.S. Geol. Surv. Bull. no. 398, 1910, p. 128, pl. 50, fig. 5. Astrodapsis sp. indet. Stefanini. Boll. Soe. geol. ital., vol. 30, 1911, p. 703. Sismondia (?) arnoldi Twitchell. U. 8S. Geol. Surv. Mon., vol. 54, 1915, pp. 182-183, pl. 85, figs. la—1b, Holotype.—No. 165538 U.S. Nat. Mus. 'Since no specimens of this species have been available for study Twitchell’s description is given here verbatim: This little echinoid, one of the smallest occurring in the Tertiary deposits of the Pacific Coast, was first figured but not described by Ralph Arnold, of the U.S. Geological Survey, in whose honor the species is named. The test is very small, being less than half an inch in diameter. In marginal outline it is sub- oval, with a slight tendency toward the subpentagonal, the anterior end being slightly angulated, the posterior broader and rounded. The whole form is much depressed, slightly convex above, slightly concave below; margin of moderate thickness. Apex central. The ambulacral petals are long, reaching the margin; poriferous zones narrow, diverging in straight lines from apex to margin; pores of both rows round. The whole test is covered with small but rather conspicuous tubercles. The apical system is central, with a conspicuous tumid madreporite. The other details could not be made out on the specimen. The peristome is relatively large, central, subcircular to subpentagonal. The ambulacral grooves appear as rather well defined, simple, straight lines for a short distance out from the peristome, beyond which they become obscure. The periproct is very small, circular, inframarginal, almost marginal. Dimensions.—Length 10.5 millimeters; width 9.5 millimeters. Related forms.—S. arnoldi resembles S. (?) coalingaensis and Scutella (?) merriami, but differs from both in having petals extending to the margin, with straight, diverging poriferous zones. Geologic horizon.—Etchegoin formation, Pliocene. Locality—F our miles southeast of northwest end of Kettleman Hills, Coalinga district, California. 62 University of California Publications in Geology [Vou.12 SISMONDIA (?) COALINGAENSIS Twitchell Plate 4, figures 3a, 3b Sismondia (?) coalingaensis Twitchell. U. 8. Geol. Surv. Mon., vol. 54, 1915, p. 183, pl. 85, figs. 2a—2e. Holotype.—No. 165717 U. S. Nat. Mus. Since no specimens of this species have been available for study Twitchell’s description is given here verbatim: The test of this species is very small, rarely exceeding one-half an inch in length. In marginal outline it is suboval to subovate, broader posteriorly than anteriorly. The whole form much depressed, slightly tumid centrally; margin rather thin. Apex subcentral or slightly eccentric posteriorly. Lower surface concave. The ambulacral petals are subelliptical in outline, extending a little more than half way to the margin; the posterior pair shorter than the anterior pair; pores round, pairs of pores conjugated. The whole test is covered with small but conspicuous tubercles, scattered irregularly. The apical system is subcentral or slightly eccentric posteriorly, coincident with the apex. The details could not be made out on the specimen studied. The peristome and ambulacral grooves could not be made out. The periproct is small, inframarginal, almost marginal. Dimensions.—Length 12 millimeters; width 10 millimeters; height 2 milli- meters. Related forms.—S. coalingaensis resembles Sismondia (?) arnoldi and Scutella (?) merriami. From the former it differs in having shorter, subelliptical petals and from the latter in lacking the tumid petals and in having a more longi- tudinally oval marginal outline. Geologic horizon.—KEtchegoin formation, Pliocene. Locality —Jacalitos Creek, half a mile east of Kreyenhagen’s, Coalinga district, California. Famity SCUTELLIDAE Agassiz Genus SCUTELLA Lamarck SCUTELLA ANDERSONI Twitchell Plate 12, figures la, 1b, le Scutella sp.a F. M. Anderson. Proc. Calif. Acad. Sci., ser. 3, Geol., vol. 2, 1905, p. 193, pl. 13, fig. 8. Scutella andersoni Twitchell. U. 8. Geol. Surv. Mon., vol. 54, 1915, pp. 183-184, pl. 85, figs. 3a—3d. Holotype.——No. 165719 U. 8S. Nat. Mus.; figured specimens nos. 11363 and 11364 Univ. Calif. Coll. Invert. Pal. Test small. Measurements of specimen no. 11363: antero-posterior diameter 25.4 mm., transverse diameter 25.4 mm., greatest height 1920] Kew: Cretaceous and Cenozoic Echinoidea 63 5.0 mm. Outline varies from subcireular to suboval or subovate ; ambitus broadly and deeply notched in the two posterior ambulacral areas, so that a lobe-like appearance is given to the posterior portion of the test; very slightly notched in the anterior ambulacral areas; greatest lateral diameter posterior to the center of the test. Upper surface much more depressed in the posterior than in the anterior part; rises from a very thin edge to a low pointed apex which is situated shghtly anterior to the center of the test; profile from margin to summit is usually somewhat concave. Apical system eccen- tric to the anterior, and in most specimens coincides with the apex of the test, though it may be posterior to the latter. Madreporic area large and subpentagonal in outline; four large genital pores present. Five small perforated radial plates are situated at the base of the petals. Ambulacra considerably wider than the interambulacra at the ambitus. Petals of moderate size and extending about two- thirds the distance from the the apical system to the margin; petals of the bivium slightly longer than the others, with the odd anterior one the shortest; rows of pores regularly curved, giving them a sub- lanceolate appearance; pores converge but little in the distal ends of the petals; odd anterior petal wide open and broader than the others. Poriferous areas relatively broad, being about two-thirds the width of the interporiferous area. Outer rows of pores slit-like in outline; inner rows smaller and suboval. Poriferous areas somewhat sunken below the general level of the test. Anterior median portion of the abactinal surface longitudinally and broadly ridged, the elevation ex- tending back into the odd posterior interambulacral area; interporif- erous areas of the lateral petals slightly elevated. Inferior surface very shghtly concave. Peristome anteriorly eccentric, relatively large, and subcireular in outline. Ambulacral furrows are broad, indistinct grooves extending to the edge of the test. Periproct large, round, and supramarginal, though in some specimens it is nearly marginal. Tubereles small, numerous, and of the same size on both surfaces. Related forms—From Scutella merriami (KF. M. Anderson) this form differs in that the periproct is supramarginal or marginal instead of being inframarginal; that it has a much thinner test, and lacks the swollen margin; that the notching of the ambitus in the ambulacral areas is greater; and that the poriferous areas are relatively narrower. These forms are closely related and may be confused due to their similarity in size and in that the raised odd anterior petal is common to both. From S. teyonensis Kew it may be readily distinguished by 64 Umiversity of Califorma Publications in Geology [Vou. 12 lacking the flaring petals, which extend close to the margin. From S. gabbi (Rémond) it is separated by its more depressed test and deep posterior ambulacral notches in the margin. It differs further from S. blancoensis Kew in that the periproct is not so strongly supra- marginal. Geologic horizon—Vaqueros formation, Lower Miocene; Tejon, Upper Eocene formation (Twitchell) (?). Associated with S. tejo- nensis Kew. Localities —Holotype from Devil’s Den District, Kern County, California (Twitchell). Figured specimens from basal beds of the Vaqueros formation in the Tejon Hills, Kern County, California, Univ. Cal. loc. 3358; near base of the Vaqueros along the road at the foot of the Casitas grade, Ventura County, California; west of Coalinga, Kern County, California (F. M. Anderson). SCUTELLA BLANCOENSIS Kew, n. sp. Plate 11, figures la, 1b, le Cotypes.—Nos. 11358, 11859, Univ. Calif. Coll. Pal. Test small. Measurements of specimen 11358: anteroposterior diameter 22.3 mm., transverse diameter 23.8 mm., greatest height 4.0 mm. Outhne subovate, pointed behind. Apical system relatively large and eccentrie anteriorly; four genital pores present. Upper surface considerably depressed, especially in the posterior area; rises to the apex, which is situated anterior to the apical system and com- paratively close to the margin; anterior part of the upper surface of the test considerably more elevated than the posterior part, and with the margin thickened. Lateral petals elliptical in outline, rather long, narrow, and extending about three-fourths the distance to the margin. Inner rows of pores converging but httle at their ends; outer rows converging close to the inner rows at the extremity of the petals with a few sporadic pores beyond the petals, the rows diverging widely. Poriferous areas comparatively wide, each being almost as wide as the interporiferous area. Odd anterior petal wide, broadly open at its extremity, and shorter than the paired petals; poriferous areas about as wide as those of the lateral petals, but the interporif- erous area is nearly twice the width; inner rows of pores diverge to the end; outer rows diverge strongly until about one-half the distance to the end, whence they continue in parallel lines, gradually coming 1920] Kew: Cretaceous and Cenozoic Echinoidea 65 closer to the inner row, and, as the distal portion is approached, both rows strongly diverge. Outer rows of pores slightly sunken in all petals. Inferior surface flat, with very faint, straight, undivided ambulacral lines in indistinct broad grooves, which do not reach the margin. Peristome subpentagonal in outline and slightly anteriorly eccentric. Periproet round, supramarginal, and placed about its own diameter from the edge of the test. Tubercles on the superior surface very small and crowded; those of the inferior surface larger and placed in well defined serobicules. Related forms.—This species closely resembles Scutella gabbi (Rémond), but it may be separated from the latter by the position of the periproct, which is situated farther from the edge of the test than in 8. gabbi, in which it is nearly marginal; the test is less elevated and slopes posteriorly to a thinner margin; the marginal outline is more subovate; and the petals are narrower and more strongly elliptical in outline. The anteroposterior profile of the test resembles S. andersoni Twitchell, but S. blancoensis may be distinguished by its lack of distinct posterior marginal notches, and from the fact that the periproct is supramarginal and not marginal. From Scutella merriamt (Anderson) it differs in being less tumid, in having a sub- ovate marginal outline, and in the strongly supramarginal position of the periproct. Geologic horizon.—San Lorenzo series, Oligocene. Localitics —Basal sandstone, sea cliffs north of hghthouse, Cape Blanco, Oregon, Leland Stanford Jr. Univ. Dept. Geol. loe., N. P. 26, and Calif. Acad. Sci. loc. no. 17. SCUTELLA COOSENSIS Kew, n. sp. Plate 8, figures la, 1b Holotype.—No. 446 Calif. Acad. Sei. Coll. Pal. Test of medium size, and greatly depressed. Measurements of holo- type: anteroposterior diameter 52 mm., transverse diameter approxi- mately 80 mm., greatest height approximately 8 mm. Marginal out- line transversely suboval. Margin thin, with the upper surface gently and regularly arched to the summit, the latter being situated slightly anterior to the center of the test. Apical system central; madreporie area large, four genital pores present opposite the four lateral corners. Ambulacra extremely wide at the ambitus, the odd anterior one being four times the width of the adjoining interambulacra, the other am- 66 University of California Publications in Geology [Vou.12 bulacra about three times the width of the adjoining areas. Petals of moderate size, symmetrical, and reaching slightly over one-half the distance from the apical system to the margin; odd anterior and posterior lateral petals of equal length and somewhat shorter than the anterior lateral pair; all of same width, with very wide poriferous areas and narrow interporiferous areas, except that of the odd pos- terior petal, which is slightly wider than the others. Inner rows of oval pores extend in nearly parallel lines to the end of the petal, converging but little at their ends; outer rows of slit-lke pores diverge at first to a much greater degree and then continue approximately parallel to the inner rows until near the extremity of the petal, when they sharply converge close to the inner rows; outer rows of pores in the odd anterior petal curve more regularly from the base to the end. Lower surface nearly flat. Periproct very small and marginal. Related forms.—This form most closely resembles the Vaqueros, Lower Miocene species, Scutella vaquerosensis Kew, but may easily be distinguished by the shape of the petals, which in S. coosensis are narrower, with wider poriferous areas in proportion to the interporif- erous areas; also the odd anterior petal of S. vaquerosensis is broader and wide open at its extremity. S. fairbanksi Arnold differs in having a supramarginal periproct, a subcireular outline, and in that the petals possess broader interambulacral areas. Geologic horizon.—Kocene series (Meganos?). Locality.—Holotype from north side of See. 4, T. 26 S., R. 14 W., west of Yokam Point, Coos County, Oregon (Calif. Acad. Sci. Coll.). SCUTELLA FAIRBANKSI Arnold Plate 11, figures 2a, 2b, 2c Scutella fairbanksi (Merriam MS.) Arnold. Proce. U. 8. Nat. Mus., vol. 32, 1907, p. 542, pl. 46, fig. 3; pl. 43, figs. 5, 5a. Scutella fairbanksi. Eldridge and Arnold, U. 8. Geol. Surv. Bull, no. 309, 1907, pl. 29, fig. 9. Scutella fairbanksi. Pack, Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, 1909, pp. 276-277, pl. 23, fig. 1. Echinarachnius fairbanksi. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 703. Seutella fairbanksi. Clark and Twitchell, U. 8S. Geol. Surv. Mon., vol. 54, 1915, pp. 184-185, pl. 85, figs. 4-6. Holotype.—No. 11017; figured specimen, no. 11360. Univ. Calif. Coll. Invert. Pal. 1920] Kew: Cretaceous and Cenozoic Hchinoidea 67 Test of medium size. Measurements of specimen 11017: antero- posterior diameter approximately 49 mm., transverse diameter 53.7 mm., greatest height 5.2 mm. Outline subcireular to transversely sub- oval, usually with broad, indistinet marginal notches in the ambu- lacral areas; test greatly depressed, with margin markedly thin. Apical system anteriorly eccentric. Upper surface arched to a low summit, which is forward of the apical system and relatively close to the anterior margin. Apical star comparatively small; madreporite large and pentagonal in shape; four genital pores present, the odd posterior one being absent. Ambulacra broader than the interambu- lacra at the ambitus. Ambulacral areas widen rapidly from the ends of the petals to the margin, but the interambulacral areas maintain a uniform size from that point to the edge of the test. Abactinal portion of the ambulacra petaloid. Lateral petals narrow and subelliptical in outline; both rows of pores converge shghtly toward the distal end of the petals, the convergence of the outer rows being greater than that of the inner rows. Poriferous areas wide, and nearly as broad as the interporiferous area. Odd anterior petal distinctly different from the others; much broader, with a greater width of the inter- poriferous area and shghtly elevated; inner rows of pores diverge somewhat near the distal end of the petal, and the outer rows converge but slightly if at all. A few pairs of pores in divergent rows continue for a short distance beyond the ends of all the petals. Pores in all petals oval in shape and conjugated. Very small scrobicular tubercles are crowded over both surfaces, but become larger and less numerous near the peristome. Inferior surface flat, with deep ambulaeral fur- rows which extend in wavy lines from the peristome to the margin; they have a slight tendeney to branch near the edge of the test. Peristome round, small, and slightly eecentrie anteriorly. Periproct round, small, supramarginal, and situated about its own diameter from the edge of the test. Related forms.—Scutella fairbanksi differs from S. gabbi (Ré- mond), to which it is closely allied, in that it attains a much greater size and has slight marginal notches in the ambulacral areas; in having deeper ambulacral furrows on the inferior surface; in that the periproct is entirely supramarginal, the test relatively thinner, and the submarginal area of the upper surface comparatively broader. With the exception of the difference that the margin is notched, these distinguishing characters separate it from the large form and notched form of S. gabbi. S. gabbi var. tenwis Kew differs in being of smaller 68 University of California Publications in Geology [Vow. 12 average size; in that the rows converge more closely toward the distal end of the petals, and in that the slope of the upper surface is more or less concave, whereas that of S. fatrbanksi is markedly convex ; more- over, the ambulacral furrows are not so prominent on the actinal surface. It may easily be distinguished from Dendraster (Calaster) interlineatus (Stimpson) and D. (Calaster) oregonensis (W. B. Clark) by its shghtly anterior eccentric apical system. Geologic horizon.—Vaqueros formation, Lower Miocene. Associ- ated with the fauna of the Turritella ineziana zone. Reported from the middle part of the Sespe formation, Oligocene( ?). Localities —Holotype from ‘‘near Torrey Canyon Wells, southwest of Piru, Ventura County’’ (Arnold) ; also oceurs ‘‘in tributary enter- ing Little Sespe Creek at the Foot-of-the-Hill Wells, Ventura County’’ (Arnold) ; Sespe Canyon, Ventura County, California (Pack, Ar- nold) ; south side of Tar Creek Canyon, Ventura County, California, Univ. Calif. loc. 2728 (Louderback). South side of Santa Clara Valley, Shiells Canyon, NW. 14 of See. 10, T.108., R. 19 W., Ventura County, California. SCUTELLA FAIRBANSKI SANTANENSIS Kew, n. var. Plate 11, figures 8a, 3b, 3¢ Cotypes.—Nos. 11861 and 11862 Univ. Calif. Coll. Invert. Pal. This form differs from the typical Scutella fairbankst Arnold in its thinner test; the profile of the upper surface from the ambitus to the summit is usually shghtly concave or straight in contrast to that of the S. fairbanksi, which is convex; the margin is more strongly notched in the ambulacral areas, giving the test a broadly subovate entline in some specimens; and the summit coincides more closely with the apical system. Related forms.—This variety is most closely allied to Scutella gabbi var. tenuis Kew than is the typical form, but differs in having a greater marginal notching in the ambulacral areas; in attaining a larger size; and in that the rows of pores do not converge so much in the distal ends of the petals. Geologic horizon—Vaqueros formation, Lower Miocene. Associ- ated with the fauna of the Turritella ineziana zone. Localities —Holotype from Santa Ana Mountains, Orange County, California, Univ. Calif. loc. 2339. 1920] Kew: Cretaceous and Cenozoic Echinoidea 69 SCUTELLA GABBI (Rémond) Plate 12, figures 4a, 4b; plate 13, figures 1, 2a, 2b, 3 Clypeaster gabbi Rémond. Proe. Calif. Acad. Sci., vol. 3, 1863, pp. 53-54. Clypeaster gabbi. Meek, Smithson. Mise. Coll., vol. 7, no. 183, 1864, p. 2. Clypeaster gabbi. Gabb, Geol. Surv. Calif. Pal., vol. 2, 1869, pp. 36, 109, pl. 12, figs. 64, 64a. Clypeaster gabbi. Cooper, Cat. Calif. Fossils, Seventh Ann. Rept. Calif. State Mineralogist, 1888, p. 27. Scutella (Clypeaster) gabbi. Merriam, Univ. Calif. Publ. Bull. Dept. Geol., vol. 2, 1898, pp. 110, 111, 113, 114, 117. Scutella gabbi. Merriam, Proce. Calif. Acad. Sci., ser. 3, Geol., vol. 1, 1899, p. 168, pl. 22, figs. 5, 5a. Echinarachnius gabbi. Stefanini, Boll. Soe. geol. ital., vol. 30, 1911, p. 703. Scutella gabbi. Kew, Univ. Calif. Publ. Bull. Dept. Geol., vol. 18, 1915, pp. 366-868, pl. 39, figs. 1-3. Scutella gabbi. Clark and Twitchell, U. 8. Geol. Surv. Mon., vol. 54, 1915, p. 189, pl. 88, figs. la, 1b. Clypeaster ? gabbi. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 1915, p. 211. : Neotype—No. 11001 Univ. Calif. Coll. Invert. Pal. Test small. Average measurements: anteroposterior diameter 25.3 mm., transverse diameter 26.3 mm., greatest height 6.3 mm. Outline circular to subcireular, subpentagonal in some specimens; transverse diameter often greater than the anteroposterior diameter ; very faintly notched at the ambitus in the posterior ambulacral areas. Upper sur- face depressed, with margin rather thin but having a tendency to be thicker in young forms. Summit usually anterior to the apical system, which is slightly eccentric anteriorly. Four large genital pores present, the one opposite the posterior interambulacral area being absent ; five small radial plates, each possessing a pore. Petals usually unequal in length; those of the trivium extend nearer to the margin than those of the bivium; posterior lateral pair longest, the anterior laterals shortest, with the odd petal usually intermediate or about as long as the posterior pair. Petals open at their ends; odd anterior one wide open. Inner rows of pores of lateral pairs of petals in almost straight lines, converging very slightly toward the end; outer rows converge to a greater degree, which in most specimens almost close with the inner rows at the distal end of the petal. Pairs of small pores continue to the margin, the pairs diverging from each other to a marked degree. Each poriferous area of about the same width as the interporiferous area, except in the odd anterior petal, where they are about one-half the width. Ambulacra widen rapidly from the ends of the petals to 70 Umversity of California Publications in Geology [Vou.12 the margin, where they are nearly twice the width of the interam- bulaera; the latter are widest opposite the ends of the petals and become narrower at the margin. Inferior surface flat to very slightly concave. Peristome small, and approximately central. Periproct mar- ginal to entirely supramarginal, small, and round. Ambulacral lines weak and seldom seen; they divide a short distance from the peristome and continue nearly to the margin. Variations.—A large form is found near the base of the San Pablo group which differs from the typical Scutella gabbi in being of larger size and having a relatively more depressed test. In the Upper San Pablo group a notched form occurs, which differs in having a some- what deeper notching at the ambitus in the ambulacral areas. It is shghtly thinner, and the petals on some of the specimens have a tendeney to be slightly raised. Related forms—wNScutella gabbi is most closely related to S. mer- riamt (EK. M. Anderson); but differs in that it has a more elevated test ; does not possess the swollen margin; lacks the greater tumidity of the anterior odd ambulacral area; and in that the periproct may be more or less supramarginal in S. gabbi whereas in S. merriami it is always marginal. S. andersoni Twitchell is distinguished from it, according to Twitchell, ‘‘....by its longitudinally ridged upper surface, its longitudinally coneave lower surface, and its pronounced marginal notches opposite the posterior paired petals.’’ According to Pack, S. fairbanksi Arnold, to which it is often compared, differs ‘ considerably in ‘‘...attaining a greater size, in having a slightly undulating marginal outline, in having deeper and better marked furrows on the actinal surface, and in having the anal pore entirely upon the upper surface.’’ Other differences show that the test is relatively thinner, and that the petals do not extend so near the margin. Geologic horizon—Lower San Pablo group, Upper Miocene, asso- ciated with S. gabbi var. tenwis Kew. oe Localities —Oceurs . abundantly on the eastern shore of San Pablo Bay, south of Mare Island in soft sandstone of Miocene age”’ (Rémond). Neotype from Contra Costa County, California. Discussion.—Doubt is expressed by Twitchell as to the synonomy of the Scutella gabbi described and figured by Merriam with that deseribed by Rémond, in as much as a few dissimilarities occur in the two descriptions. A great many specimens are at the writer’s disposal in the collections of the University of California, which have - 1920] Kew: Cretaceous and Cenozoic Echinoidea 71 been collected from the type locality of the ‘‘eastern shore of San Pablo Bay south of Mare Island, California, in soft sandstones of Miocene age.’’ The types used by Merriam were from the same locality. Twitchell enumerates three sets of details in which the two de- scriptions differ. These are as follows (quoting from Twitchell) : ‘‘Rémond’s was subelevated, comparatively thick and with margin rounded. Merriam’s is much depressed, and with margin thin. The petals of Rémond’s form were elongated and open at their extrem- ities—those of Merriam’s are short and, excepting the anterior one, are nearly closed at the ends. In Rémond’s form the ambulacral furrows are straight, which led to his placing the form in the genus Clypeaster; in Merriam’s the furrows divide dichotomously a little less than half way to the margin, which indicates a Scutella.’’ The terms used by both Rémond and Merriam are for the most part rela- tive, and their meaning is dependent upon the manner in which the respective authors used them. For this reason the writer has con- cluded that the first two sets should in this ease be considered as of little value in the determination of the similarity of the two forms. In the third difference, whether the ambulacral furrows divide or not, it was found, after examining a great number of specimens, that straight, shallow, indistinct furrows do exist, but that in some cases dichotomously bifureating ambulacral lines are present. This, it is believed, is sufficient evidence for placing this species in the genus Scutella. Only one specimen in the large collection available was found which had bifureating lines, though several forms showed the ambulacral furrows. This last character is probably what Rémond saw and used as the basis of his determination of the genus. SCUTELLA GABBI var. TENUIS Kew Plate 13, figures 4a, 4b Scutella gabbi var, tenuis Kew. Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, 1915, pp. 368-369, pl. 39, fig. 4. Holotype-—No. 11005; figured specimen no. 11370, Univ. Calif. Coll. Invert. Pal. This form is characterized by its extreme thinness. It is larger than Scutella gabbi Rémond. Average measurements: anteroposterior diameter 33.5 mm., transverse diameter 34.5 mm., greatest thickness 5.8 mm. It is more strongly depressed; its edge is much thinner, 72 University of California Publications in Geology [Vou 12 and the notching in the ambulacral areas is deeper. It resembles Scutella fairbanksi Arnold, but differs in its smaller size and in that the rows of pores of the petals converge more strongly in the distal part. The ratio between the length of the petals and the distance from the apical system to the ambitus is less in S. fairbanksi than in S. gabbi var. tenuis, but the ratio of the latter compared with the same ratio in S. gabbi shows a close resemblance. S. gabbi , S. gabbi var.tenuis S. fairbanksi Average length of odd anterior petal — .6905 674 5945 Average distance from apical system to ambitus The ratio of the length of the petals of the bivium to the distance from the apical system to the ambitus shows similar results. It may be separated from Scutella andersont Twitchell by its less strongly notched margin in the posterior ambulacral areas; by its more nearly circular outline, and its thinner test. Geologic horizon.—Immediately above the basal beds in the San Pablo group, Upper Miocene. Locality —Holotype from San Pablo Bay district, Contra Costa County, California. , SCUTELLA MERRIAMI (F. M. Anderson) Plate 12, figures 3a, 3b, 3c, 3d, 3e, 3f Astrodapsis merriami F. M. Anderson, Calif. Acad. Sci., ser. 3, vol. 2, 1905, pp. 193-194, pl. 14, figs. 33, 34. Scutella merriami. Arnold, U. 8. Geol. Surv. Bull., no. 396, 1909, p. 18, pl. 6, fig. 4. Scutella merriami. Arnold and R. Anderson, U. 8. Geol. Surv. Bull. no. 398, 1910, pp. 85, 86, 87, pl. 38, fig. 4. Scutella (2?) merriami. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 1915, pp. 185-186, pl. 85, figs. 7a, 7b, 7c, 8a, 8b. Sismondia merriami. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 702. Cotypes.—Nos. 53 and 54 Calif. Acad. Sei. Coll. Pal. Test small. Measurements of specimen no. 53: anteroposterior diameter 22.8 mm., transverse diameter 22.7 mm., greatest height 3.2 mm. Subcireular in outline, and with upper surface greatly de- pressed ; margin swollen, and usually broadly notched in the ambu- lacral areas, the notching being more prominent in the two posterior areas. Apical system anteriorly eccentric; apex slightly anterior to the apical system. Lateral petals wide, partially closed, the pores 1920] Kew: Cretaceous and Cenozoic Echinoidea 133 converging but little toward the extremities of the petals ; odd anterior one wide open, the rows of pores not converging. Petals of the trivium reach nearly to the margin of the test, but those of the bivium only about two-thirds the distance to the margin. Odd anterior petal somewhat elevated, forming the highest portion of the test. The angle between the anterior lateral petals very wide, being almost 180°, whereas the angle between the petals of the bivium is about 60°. Pores conjugate and extend in parallel rows beyond the ends of the petals almost to the margin; each poriferous area approximately equal to the interporiferous area in the lateral petals; the interporiferous area of the odd petal is wider. Actinal surface flat. Peristome slightly sunken. Ambulacral furrows usually obliterated, but when visible are broad, straight, and undivided. In some specimens ambulacral lines are present, which tend to bifureate. Periproect marginal. In- ternal structure consists of radial partitions with connecting supports near the periphery of the test. Related forms.—This species differs from Scutella gabbi (Rémond ) mainly in the more depressed test ; more swollen margin; in the eleva- tion of the odd anterior petal; and in the constant marginal position of the periproct. It also resembles S. andersoni Twitchell, but may be distinguished from this form by the lack of the posterior marginal lobe in the odd interambulacral area; in its thicker and more swollen margin ; in the marginal position of the periproct, which in S. andersoni is supramarginal. WS. tejonensis Kew may be easily separated by its wide open, flaring petals. - Geologic horizon.—Lower part of Monterey group, Lower Miocene (?). Oceurs in beds associated with the Turritella ocoyana zone fauna. Localities —Cotypes in Calf. Acad. Sei. Coll. from along the east side of the Temblor Range in Kern County, California; also occurs in Tejon Hills, Kern County, California, and about one mile north of El Toro, Orange County, California. SCUTELLA NEWCOMBEI Kew, nu. sp. Plate 8, figures 2a, 2b Holotype.—No. 11356 Univ. Calif. Coll. Invert. Pal. Test of medium size. Approximate measurements of holotype: anteroposterior diameter 40 mm., transverse diameter 44 mm., greatest elevation 7.8 mm. Outline subcireular, with margin truneated in the 74 University of California Publications in Geology [Vou. 12 odd anterior ambulacral area; margin slightly thicker in the anterior part. Apical system anteriorly eccentric to a slight degree. Upper surface much depressed; rises gradually to a low apex, which is anterior to the apical system. Ambulacral area nearly twice the width of the interambulacra at the ambitus; ambulacra petaloid. Lateral petals subelliptical in outline; angle between the axes of the anterior lateral petals is nearly 180°. Inner rows of pores diverge gradually for about two-thirds the length of the petal and then converge slightly to the end. Outer rows diverge somewhat more at first and converge to a greater degree in the distal end. This arrangement of pores gives the petals an appearance of having a slight tendency to be closed at their extremities. Each poriferous area about one-half the width of the interporiferous area. Odd anterior petal wider than the others, due to the greater width of the interporiferous area ; inner rows of pores in this petal diverge to the end; outer rows converge shghtly in the distal part. This arrangement gives the petal a wide open, or flaring appearanee. All petals extend about two-thirds the distance to the margin. Inferior surface flat, with ambulacral furrows extending from the peristome to the margin, and in the specimen ex- amined appear to be simple and undivided. Peristome central, rather large, and round. Periproct small, inframarginal, and situated about midway from the posterior margin to the mouth. Tubercles on the upper surface small and crowded; those on the inferior surface some- what larger, and placed in distinct scrobicules. Related forms.—This form seems to be closely related to Scutella blancoensis Kew, but differs in that it is considerably larger and does not possess the angular posterior margin; the petals do not extend so near to the margin; the angle between the two anterior lateral petals is greater, the axes of the two forming an approximately straight line; the anterior margin in the odd ambulacral area is truncated; and the poriferous areas of the petals are somewhat narrower. It also resembles S. gabbi (Rémond), large form, but may easily be dis- tinguished by its larger size, and the truncation of the margin in the anterior ambulaeral area. In this latter character it is like S. facr- banksi Arnold, but differs from this species in having wider and much longer petals which are flush with the surface of the test, whereas on S. fairbanksi they have a slight tendeney to be raised. Geologic horizon.—Sooke beds, Oligocene ? Localities —Holotype from Slide Hill Beach, Vancouver Island, British Columbia, Leland Stanford Jr. Univ. Dept. Geol. loc., N. P. 181. 1920] Kew: Cretaceous and Cenozoic Echinoidea 15) SCUTELLA NORRISI Pack Plate 10, figures la, 1b Scutella (?) norrisi Pack, Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, 1909, pp. 277-278. Scutella norrisi Pack, Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, 1913, pp. 299-300, pl. 15, fig. 1. Echinarachnius norrist. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 703. Scutella norrist. Clark and Twitchell, U. 8. Geol. Surv. Mon., vol. 54, 1915, pp. 186-187, pl. 85, fig. 9. Holotype.—No. 11028; lectotype, specimen no. 11027, Univ. Calif. Coll. Invert. Pal. Test large. Measurements of specimen no. 11027: anteroposterior diameter 73 mm., approximate transverse diameter 98 mm., greatest height 7 mm. Marginal outline, in general, subcireular to subpen- tagonal, but very irregular, due to the presence of broad, deep mar- ginal notches in the ambulacra, the two posterior ones being much greater than the anterior ones; this gives the test the appearance of a maple leaf; the margin is also cut by slight indentations at the sutures between the ambulacral and interambulacral areas. Test very thin, with abactinal surface greatly depressed and rising but little to the apex, which coincides with the apical system. Apical system eccentric shightly to anterior of the center of the test. Madreporie area large, pentagonal, and with four genital pores situated at each of the corners, excepting the odd posterior one. Ambulacra about two-thirds the width of the interambulacra at the ambitus. Ambu- lacra petaloid. Petals symmetrical, of the same length, and extending about three-fifths the distance to the margin; those of the bivium slightly narrower than those of the trivium. Rows of pores extend in divergent lhnes for about two-thirds the length of the petal, and then converge very slightly to the end, which gives the petal a nearly wide open appearance; each poriferous area equal to about one-third the width of the interporiferous area. Petals of small specimens are slightly tumid. Inferior surface faintly concave to the mouth. Peris- tome small, subcircular, and subcentrally located. Broad, deep, straight ambulacral furrows extend to the margin ; indistinet branches are given off about two-thirds the distance to the edge of the test. Periproct small, round, and inframarginal, almost marginal. Related forms.—Scutella norrisi is one of the most distinctive Lower Miocene echinoids of California. It resembles S. andersoni 76 University of California Publications in Geology [Vou.12 Twitchell, but S. norrist may be easily distinguished by its much larger size, relatively more depressed test, inframarginal periproct, usually deeper posterior ambulacral marginal notches which, in some specimens, are of nearly the same relative size, petals wider open at their extremities, and by the fact that the rows of pores converge more at the ends of the petals. It is most closely allied to S. vaquwerosensis Kew, but differs in having deeper marginal notches and in that the petals are wider open at their extremities. Geologic horizon.—V aqueros formation, Lower Miocene, associated with the fauna of the Turritella ineziana zone. Localities —Holotype from ‘‘ Eastern Monterey County, five miles northwest of Stone Canyon Coal Mine’’ (Pack) ; lectotype from ‘‘. . . near mouth of the Alizo Canyon in the southern end of the San Joaquin Hills, south of Santa Ana, Orange County, California’’ (Pack), Univ. Calif. loc. 1157; at La Panza, on the San Juan River, and in the mountains between the San Juan River and the Carrizo Plains, San Luis Obispo County, California; Santa Ana Mountains, Orange County, California. SCUTELLA TEJONENSIS Kew, n. sp. Plate 12, figures 2a, 2b Holotype —No. 11365 Univ. Calif. Coll. Invert. Pal. Size small. Measurements of holotype: anteroposterior diameter 26.0 mm., transverse diameter 25.6 mm., greatest height 4.6 mm. Out- line of test subcircular, and with broad angular notches in the ambitus in the posterior ambulacral areas; also a distinct notch in the odd interambulacral area; margin rounded. Posterior portion of the sur- face of the test more depressed than the anterior part. Apical system decidedly eccentric to the anterior, with the summit of the test shghtly in front of the latter. Petaliferous portions of the ambulacral areas extend almost to the edge of the test; each poriferous area equal in width to about one-half the interporiferous area. Both outer and inner rows of pores diverge continuously ; the inner rows to a greater degree near their distal ends, where they come close to the outer rows ; odd anterior petal broader than the others and somewhat elevated. This form of petal contrasts markedly with the petals of other Cali- fornia echinoids, the latter always possessing more or less convergent rows of pores. Inferior surface slightly concave. Peristome round 1920] Kew: Cretaceous and Cenozoic Echinoidea 17 and slightly eccentric anteriorly. Periproct marginal, of small size, and placed in the posterior interambulacral notch. Related forms.—This species very closely resembles Scutella ander- sont Twitchell, with which it is associated, in size, outline, and in the wide and slightly elevated odd anterior petal. It differs in its thicker and more rounded margin ; more eccentri¢ apical system ; in the flaring appearance of the petals, in contrast to the usually lanceolate type of the former; in that the petals extend nearer the margin; and in the position of the periproct, which is in a distinct marginal notch. Only one specimen of this species is known. Although quite dis- similar from Scutella andersoni, there seems to be a gradation between the two species in the shape of petals, the most distinctive feature. The petals of the bivium in the latter form are often flaring to a shght degree like those of S. tejonensis. These forms, including SV. merriamt (Anderson), are probably closely related species. Geologic horizon—Vaqueros formation, Lower Miocene. Associ- ated with S. andersoni Twitchell. Locality.—Tejon Hills, Kern County, California, Univ. Calif. loe. 3358. SCUTELLA VAQUEROSENSIS Kew, n. sp. Plate 8, figure 3; plate 9, figures la, 1b, le Cotypes.—Nos. 11403 and 11404 Univ. Calif. Coll. Invert. Pal. and no. 447 Calif. Acad. Sei. Coll. Pal. Test large, markedly thin. Measurements of specimen 447: antero- posterior diameter 67 mm., transverse diameter 81.2 mm., greatest height approximately 8 mm. Outline undulating, truneated behind, and rounded anteriorly ; transverse diameter greater than the antero- posterior diameter, with greatest breadth immediately posterior to the center of the test; broadly notched in the paired ambulacral areas, slightly so in that of the odd anterior one. Upper surface greatly depressed and rising gently from a very thin margin and nearly flat submarginal area to the apex, the latter being either coincident with the apical system or shghtly anterior to it on the odd anterior petal ; the greatest elevation is within the area limited by the length of the petals. Apical system slightly eecentrie to the anterior. The four genital pores remarkably small. Ambulacra much wider than the interambulacra at the ambitus, that of the odd anterior being twice as wide as the adjoining interambulaera. Dorsal portions of the 78 University of Californa Publications in Geology [Vou. 12 ambulacra petaloid. Petals broad, shghtly elevated, and extending more than one-half the distance from the apical system to the ambitus; the posterior pair the longest, with the odd anterior pair somewhat shorter than the others. Odd petal differs from the paired ones in that it is considerably wider, and the rows of pores do not tend to converge at their extremities. Inner rows of pores of the paired petals converge shghtly near the extremity ; outer rows at first diverge and then converge to a greater degree, joining the inner rows at the ends of the petal. Interporiferous area about twice the width of each poriferous area, except in the odd anterior petal, in which it is much wider, though the poriferous area has the same width as in the other petals. Inferior surface nearly flat, faintly concave to the mouth. Peristome round and of comparatively small size. Ambulacral fur- rows well marked, straight, undivided, and extend to the edge of the test. Periproct round, small, and situated in a small notch in the margin. Related forms——This Lower Miocene Scutella is most closely re- lated to Scutella fairbanksi Arnold, from which it differs in that it is much larger and has a more depressed test, the upper surface is less regularly rounded to the summit, and the periproct is strictly marginal, whereas in the SN. fairbanksi it is supramarginal. It is separated from S. norrisi Pack by having less pronounced triangular marginal notches, and by petals which are not fully open at their extremities. Geologic horizon.—Upper part of Vaqueros formation, Lower Miocene; associated with Turritella ineziana Conrad and Pecten mag- nolia Conrad. Locality—Specimen 447 from NE. 14 of Sec. 16, T. 20 8., R. 6 E., Vaqueros Creek, Monterey County, California, locality 140, Calif. Acad. Sei. Coll. Pal.; cotypes from Salinas River district (Leland Stanford Junior Univ. Coll. Pal.). Genus ASTRODAPSIS Conrad (emended) Astrodapsis Conrad. Proce. Acad. Nat. Sci. Phila., vol. 8, 1856, p. 315; U.S. Pac. R. R. Expl., vol. 7, Pal. Rept., 1857, p. 196. Astrodapsis. Rémond, Proe. Calif. Acad. Sci., vol. 3, 1863, p. 52. Astrodapsis. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 1915, Ds LOT Genotype.—Astrodapsis antiselli Conrad, specimen no. 165466a U. S. Nat. Mus. i 1920] Kew: Cretaceous and Cenozoic Echinoidea 19 Test more or less depressed ; thickly subdiscoidal to broadly sub- conical in shape; marginal outline subeireular to subelliptical, with the anteroposterior diameter usually the greater; margin quite thin to very thick and swollen, and with or without notches in the ambu- lacral and interambulacral areas. Petaliferous areas of the ambulacra more or less elevated. Interambulacral areas more or less depressed ; auxiliary groove may be present in the ambulacral areas along the sides of the petals. Petals straight, extending close to the margin, and wide open at their extremities. Poriferous zones nearly parallel, or continuously divergent, or divergent, convergent, and again diver- gent; ambulaeral plates begin to broaden before end of the petal is reached; sporadic pores usually continue to the margin beyond the petal proper. Apical system central or subcentral, more or less de- pressed ; four genital pores present, the odd posterior one being absent. Summit of test central or anteriorly eccentric. Inferior surface flat or coneave. Peristome central or subecentral. Periproct round, infra- marginal to marginal; never supramarginal. Main ambulacral fur- rows are usually well marked, broad, and continue from the peristome to the margin, often extending as faint grooves on the upper surface nearly to the apical system and forming a median line on the petals. Indistinet lines or grooves may be thrown off from the main furrows when about two-thirds the distance to the margin, and these usually extend on to the superior surface as sutural lines between the inter- ambulacral and ambulacral areas. Tubereculation prominent, serobic- ular, of uniform size, or larger on the petaliferous portions of the ambulacra and inferior surface. Internal structure similar to that of Scutella; consists of strong radial partitions which connect with the roof for about one-fourth the distance to the peristome and then continue as ridges on the floor; concentrically placed ridges are placed near the margin, connecting the radial partitions; remainder of the floor more or less roughened. Discussion.—The early forms of Astrodapsis, such as A. brewer- tanus (Conrad), are closely related to Scutella. Although this species shows several features characteristic of Scutella, nevertheless it is placed in the genus Astrodapsis for the reason that it shows a perfect gradation into true astrodapsid forms, A. brewerianus var. diabloensis and A. cierboensis. Astrodapsis is usually distinguished by having either raised petals or depressed interambulacral areas, or both. How- ever, in A. brewerianus both of these characters are lacking. On the other hand, it has the rather thickened test, simple ambulacral furrows 80 University of California Publications in Geology [Vou.12 (which in most specimens are very indistinct), and petals which reach nearly to the margin, whereas Scutella is usually thin, with relatively well developed ambulacral furrows and a wide submarginal area. The genus later becomes more highly developed, the elevation of the petals and the interambulacral depressions becoming more pronounced ; finally in the Lower Etchegoin (Jacalitos) formation and the upper- most part of the San Pablo formation a secondary set of grooves 1s acquired, these being the depressions in the ambulacral areas along the sides of the petals. The ambulacral furrows also become deeper and with distinct branches near the margin, all extending on the upper surface. The internal structure is similar to that of Scutclla, having the radial partitions in the interambulacral areas; but, on the other hand, it does not have the degree of complexity of the concentric pillars, these being in some species, such as A. brewertanus, poorly developed. Moreover, in Astrodapsis the radial partitions do not extend nearly as far in toward the peristome as in Scutella. ASTRODAPSIS ALTUS Kew Plate 15, figures 4a, 4b Astrodapsis altus Kew. Univ. Calif. Publ. Bull. Dept..Geol., vol. 8, 1915, pp. 3871-372, pl. 40, figs. 3a—3b. Holotype.—No. 10065 Univ. Calif. Coll. Invert. Pal. Test small. Average measurements: anteroposterior diameter 34.6 mm.; transverse diameter 31.5 mm.; greatest thickness 10.6 mm. Subcircular to subpentagonal in outline; margin thick; superior sur- face rising immediately from the ambitus to the summit, which is comparatively high and anterior to the apical system, thus giving the test a distinctly conical shape. Ambitus slightly notched in the pos- terior ambulacral areas. Ambulacra petaloid; petals slightly elevated and wide open. Pores conjugate; inner rows of rounded pores extend to the margin in almost straight lines, converging but little; outer rows of elongated pores converge close to the inner rows near the margin, where they become rounded and continue parallel with the inner rows to the ambitus. Interambulacral areas flat. Anus infra- marginal. Inferior surface flat and lacking ambulacral furrows. Tubereles small and set close together. 1920] Kew: Cretaceous and Cenozoic Echinoidea 81 Related forms.—This form resembles Astrodapsis tumidus Rémond, but differs in that the apical system is much more elevated, thus giving the test a more distinctly conical appearance; ambulacral fur- rows are not present on the under surface, and the superior surface shows no interambulacral depressions. Its conical shape also distin- guishes it from the other San Pablo species. It differs from Astro- dapsis cierboensis Kew in its subpentagonal outline, in contrast to the commonly elliptical outline of the latter; and from Astrodapsis (?) pabloensis (Kew) in its smaller size and the greater thickness of the test. Geologic horizon—Upper San Pablo group, Upper Miocene ; asso- ciated with Astrodapsis tumidus Rémond and Astrodapsis twmidus (small thick form). Locality —Mt. Diablo region, Univ. Calif. loc. 1950 (holotype). ASTRODAPSIS ANTISELLI Conrad Plate 19, figures 2a, 2b, 2c Astrodapsis antiselli Conrad. Proe. Acad. Nat. Sci. Phila., vol. 8, 1856, p. 315; U.S. Pace. R. R. Expl. Rept., vol. 7, 1857, p. 196, pl. 10, figs. 1, 2. Astrodapsis antiselli. Meek, Smithson. Mise. Coll., vol. 7, no. 183, 1864, p. 2. Astrodapsis antiseli. Gabb, Calif. Geol. Surv., Pal., vol. 2, 1869, p. 110. Astrodapsis antiselli. Cooper, Seventh Rept. State Mineralogist California, 1887, p. 270. Astrodapsis antiselli. Merriam, Univ. Calif. Publ. Bull. Dept. Geol., vol. 2, 1898, pp. 110, 112. Astrodapsis antiselli. Arnold, Proc. U. 8. Nat. Mus., vol. 34, 1908, pl. 35, fig. 10. Astrodapsis antiselli. Arnold, U. S. Geol. Surv. Geol. Atlas, Santa Cruz folio (no. 163), 1909, pl. 2, fig. 58. Astrodapsis antiselli. Stefanini, Boll. Soc. geol. ital., vol. 30, 1911, p. 702. Astrodapsis antiseli. McLaughlin and Waring, Calif. State Min. Bur. Bull., no. 69, 1914, map folio, fig. 37. Astrodapsis antiselli.. Clark and Twitchell, U. S. Geol. Surv. Mon., vol. 54, 1915, pp. 198-199, pl. 94, figs. 3, 4a, 4D. Holotype—No. 165466a U. S. Nat. Mus.; figured specimens, nos. 11372 and 11373, Univ. Calif. Coll. Invert. Pal. Test of medium size. Measurements of specimen 11373 Univ. Calif. Coll. Invert. Pal.: anteroposterior diameter 60 mm., transverse diam- eter 50 mm., greatest height approximately 12 mm. Subeireular to suboval in outline; upper surface considerably depressed; margin thickened and rounded, and with very slight notching in the posterior 82 University of California Publications in Geology [Vou.12 ambulaeral areas in some specimens. Apical system sunken, central to slightly subeentral, and coinciding with the summit; madreporic area pentagonal; four oval genital pores present, the odd posterior one being absent; five perforated radial plates are situated at the base of the petals. Ambulacra one and a-half times the width of the inter- ambulacra at the margin. Ambulacral areas petaloid. Petals of moderate width and extending close to the edge of the test ; poriferous areas very narrow, with correspondingly wide interporiferous area. Odd anterior petal somewhat narrower than the lateral petals. Inner rows of pores round, not converging toward their extremities; outer rows of pores transversely elongate and converging close to the inner rows when about half the distance to the margin, from which point both rows continue in nearly parallel lines to the margin, the double rows diverging from each other when about three-fourths the distance to the margin. Pores conjugated. Petals elevated above the general surface of the test. Interambulacral areas grooved from the apical system to the margin; secondary grooves faintly present along the sides of the petals in the ambulacral areas, which together with the interambulacral depressions form two triangular facets on the surface of the test between the petals. Inferior surface slightly concave. Main ambulacral grooves are straight, broad, and deep near the peris- tome, and continue over the edge on the upper surface, forming a median line on the petals; the suture between the ambulacral and interambulacral areas is marked by a broad, distinct line on both upper and lower surfaces. Peristome central, large, and circular to subpentagonal in outline. Periproct large, round, inframarginal, and situated near the edge of the test. Tubereulation prominent, consist- ing of rather large, scrobicular tubereles, which are the same size on both surfaces, except on the depressed portions of the test and in the ambulacral area near the peristome, where they are somewhat smaller ; not crowded, but more numerous on the under side. Internal struc- ture consists of heavy radial partitions which reach from the roof to the floor and extend from the inside edge about one-fourth the dis- tance toward the center; disconnected concentric ridges are present, in the spaces between the double rows of radial partitions; the re- mainder of the floor is more or less roughened. Related forms.—This species differs from Astrodapsis twmidus Rémond, which it most closely resembles, in that the interambulacral grooves are shallower, that it has a thicker but relatively more de- pressed test, less elevated petals, and less numerous but more promi- 1920] Kew: Cretaceous and Cenozoic Echinoidea 83 nent and larger tubercles. From A. whitneyi Rémond it differs in lacking the bell-shaped appearance of the former, in the wider petals, and the much thicker margin. It may be separated from A. cier- boensis (Kew) by its much larger tubereles and more prominent ambulacral furrows. Geologic horizon—Upper San Pablo group (Santa Margarita for- mation), Upper Miocene. This species is found associated with Astro- dapsis margaritanus Kew. Localities —Type of Conrad from Estrella, Monterey County, Cali- fornia. It also occurs at Pence Enrico Canyon, Monterey County, Univ. Calif. loe. 2727; mouth of Swains Canyon, north of Bradley, Monterey County (U.S. Geol. Surv. Coll.) ; two miles south of San Lucas, Monterey County (U. 8S. Geol. Surv. Coll.) ; Slacks Canyon, Monterey County (Stanford Univ. Coll.) ; Wildhorse Canyon, Mon- terey County (U.S. Geol. Surv. Coll.) ; three miles above San Lucas (Stanford Univ. Coll.) ; Seott Valley, Santa Cruz County, California (Stanford Univ. Coll.). ASTRODAPSIS ARNOLDI, subsp. ARNOLDI (Pack) Plate 21, figures 3a, 3b, 3c Astrodapsis antiselli var. arnoldi Pack. Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, 1909, pp. 279-281, pl. 24, figs. 1, 2. Not Astrodapsis arnoldi (Twitchell). Clark and Twitchell, U. 8. Geol. Surv. Mon., vol. 54, 1915, pp. 199-200, pl. 95, fig. 1. Holotype.—No. 11030 Univ. Calif. Coll. Invert. Pal. Test moderately large. Measurements of holotype: anteroposterior diameter 60 mm., transverse diameter 58.6 mm., greatest height 14.9 mm. Outline subcireular, with longitudinal axis slightly longer than the transverse axis; greatest. transverse diameter somewhat posterior to the center of the test. Margin rounded and slightly but broadly notched in the ambulacral areas, the degree of notching being greater in the two posterior areas. Upper surface considerably depressed in the submarginal area, from which part it rises markedly to a rather high apex, giving rise to a bell-shaped appearance, as in Astrodapsis whitneyi Rémond. Broad, deep depressions exist in the interambu- lacral areas of the upper surface; smaller ones are present along the sides of the distal portions of the petals in the ambulacral areas. The greatest elevation of the test is on the odd anterior petal immediately in front of the very slightly posteriorly eccentric apical system. 84 University of California Publications in Geology [Vou 12 Apical system pentagonal in outline; four large genital pores and five perforated radial plates present. Petals wide; width of each poriferous zone equal to about one-half the width of the interporif- erous area; inner rows of pores diverge gradually until about one-half the distance to the margin, when they converge for a short distance and then diverge, continuing with rounded pores to the margin; the initial divergence of the outer rows of slit-like pores is greater than that of the inner rows, and when about two-thirds the distance to the margin converge close to the latter, continuing nearly to the ambitus; pores conjugated. Petals are considerably elevated near the apical system, but become lower toward the margin and in some specimens are nearly flush with the surface of the test in the submarginal area. Odd anterior petal differs from the others in that the inner rows of pores do not converge. Lower surface flat or slightly concave ; peris- tome small, rounded, and slightly eccentric to the posterior, being opposite the apical system. Broad, deep, straight ambulacral grooves are present, which pass through the marginal notches and continue on the petals as a median line or groove; at a point slightly over one- half the distance to the margin auxiliary lines are thrown off which pass to the upper surface as sutural lnes between the ambulacral and interambulacral plates. Periproct small, round, and inframar. ginal, nearly marginal. Tuberculation consists of prominent scrobic- ular tubercles on the petals and ridges between the grooves on the upper surface, grading into minute ones in the depressions; those on the inferior surface placed close together and nearly as large as the tubereles on the petals. Related forms—Pack originally described this form as a variety of Astrodapsis antiselli Conrad, calling it A. antiselli var. arnoldt. Later Twitchell raised it to a species, A. arnoldi Twitchell, and in- cluded under it a form previously identified by Arnold as A. whitneyt Rémond ; Twitchell has used the latter as his type. This was entirely erroneous, as the two forms are markedly different. The writer, with considerable material at hand, has deemed it advisable to retain the specific rank of A. arnoldi, which according to the rules of nomencla- ture takes the name Astrodapsis arnoldi (Pack). This leaves the form deseribed by Twitchell under A. arnoldi nameless. To this the writer has given the name A. californicus Kew. This form differs from Astrodapsis antiselli Conrad in having rela- tively narrower petals which are more elevated, a thinner margin, and a less depressed test; in having a bell-shaped profile, while that 1920] Kew: Cretaceous and Cenozoic Echinoidea 85 of A. antiselli is biscuit-shaped; and in that the poriferous areas of the petals are comparatively wider. From A. californicus Kew, the species which Twitchell grouped under A. arnold: (Pack), it may be easily separated, for A. californicus is larger, has a thinner test, greatly sunken interambulacral areas, and no grooves along the sides of the petals. In contrast with A. arnoldi peltoides (Anderson and Martin), A. arnoldi (Pack) has much wider petals, and usually a rela- tively thicker margin. In general shape it resembles A. whitneyr Rémond, but differs in having larger tubercles, a thicker margin, wider petals, and interambulacral and ambulacral grooves. The small grooves along the petals also separate it from A. twmidus Rémond. Geologic range-—Lower Etchegoin (Jacalitos) formation, Lower Pliocene. Associated with A. arnoldi var. fresnoensis Kew and A. arnoldi var. depressus. Localities —Holotype from Monterey County, California. Also occurs in the Coalinga District, Fresnc County, California, Univ. Calif. loc. 2969 and 2973; Indian Valley, Goat Canyon, and Lynch Creek of the Salinas Valley District, California. ASTRODAPSIS ARNOLDI DEPRESSUS Kew, n. var. Plate 23, figures 2a, 2b, 2c Holotype.—No. 11038 Univ. Calif. Coll. Invert. Pal. This form is distinguished from Astrodapsis arnoldi (Pack) by its depressed test and by not having a bell-shaped appearance like the latter, the upper surface being regularly rounded. Gradations can be found between the two forms, and for this reason only a varietal distinction is made. Geologic horizon.—Lower Etchegoin (Jacalitos) formation, Lower Pliocene. Associated with Astrodapsis arnoldi arnoldi (Pack) and Astrodapsis arnoldi var. fresnoensis Kew. Localities —Coalinga district, Fresno County, California, Univ. Calif. locs. 2969 and 2973. ASTRODAPSIS ARNOLDI CRASSUS Kew, n. subsp. Plate 23, figure 1; plate 24, figures la, 1b, le Holotype.—No. 11350 Univ. Calif. Coll. Invert. Pal. Test moderately large. Measurements of specimen no. 11350: anteroposterior diameter 62 mm., transverse diameter 52 mm., greatest 86 University of Californa Publications in Geology (Vou. 12 height 17 mm. Marginal outline suboval to subcireular, with indis- tinet notches in the posterior ambulacra and a slight lobing of the odd interambulacral area. Upper surface considerably depressed, but regularly arching to a low apex, which is usually a short distance anterior to the center of the test; interambulacra markedly grooved from the apical system to the edge of the test; shallower grooves are present along the sides of the petals in the ambulacral areas. Apical system central. Petals elevated and extending nearly to the margin. Inner rows of pores diverge at first and then continue in approxi- mately parallel lines until close to the edge of the test, when they again diverge slightly ; outer rows diverge to a greater degree at first and then converge slightly to the point where the inner rows start to diverge for the second time, and continue parallel to the latter from this point to the margin. In some specimens the inner rows may converge slightly. Poriferous areas narrow, each being about one- fourth the width of the interporiferous area. Actinal surface concave. Peristome central, large, and ecireular in outline; slightly sunken. Ambulaeral furrows deep near the peristome, becoming indistinct near the margin, and then passing into nes which usually extend over the upper surface nearly to the apical system as median lines on the petals; faint lines are given off from the main furrows when slightly over half the distance to the margin, and these continue over the upper surface as sutural lines between the ambulacral and interam- bulacral plates. Periproct relatively small, sunken, and with the immediate area surrounding it somewhat swollen. Numerous serobicu- lar tubercles are of the same size on both surfaces, except in the depressed portions of the abactinal side, where they are smaller. Related forms.—This form is closely related to the other members of the Astrodapsis arnoldi group, but may be distinguished by its relatively large peristome, by the posterior lobing in the odd inter- ambulacral area, and by its comparatively narrow petals with the rows of pores in approximately parallel lines. Geologic horizon —Lower Etchegoin (Jacalitos) formation, Lower Pliocene. Localities —Holotype from south of Pancho Rico Creek in NW. 44 of Sec. 8, T. 22 §., R. 11 E., Univ. Calif., loc. 3127; also occurs at Lynch Creek, Salinas Valley district, Monterey County, California. A small form of this species oceurs at a locality on the Hog Canyon road, See. 7, T. 24 8., R. 14 E., Monterey County, California. 1920] Kew: Cretaceous and Cenozoic Echinoidea 87 ASTRODAPSIS ARNOLDI FRESNOENSIS Kew, n. var. Plate 23, figures 3a, 3b, 3c Holotype.—No. 11032 Univ. Calif. Coll. Invert. Pal. Test of medium size. Measurements of holotype: anteroposterior diameter 50.5 mm., transverse diameter 47.3 mm., greatest height 12 mm. Outline from above subcircular; margin thickened and notched in the ambulacral areas, the degree of notching being greater in the two posterior ones. Test somewhat inflated, with the upper surface evenly arched to the summit, which is slightly anterior to the center and near the base of the odd anterior petal. Well marked interam- bulacral grooves extend from the apical system to the margin, and less prominent grooves are present along the sides of the petals in the ambulacral areas. Apical system comparatively small, and situ- ated in the center of the abactinal surface. Petals of the same size, symmetrical, noticeably narrow, and extending wide open to the margin; in most specimens they are highly elevated near the apical system, but tend to merge with the general surface near the edge of the test. Poriferous areas narrow, each area being about one-third the width of the interporiferous area. Both inner and outer rows of pores extend in shghtly diverging lines for about two-thirds the dis- tanee to the ambitus and then the double rows diverge to a much greater degree, giving the distal portion of the petals a flaring ap- pearance. Inferior surface concave. Peristome central, relatively small, and round in outline. Ambulacral furrows deep and broad; extend undivided to the ambitus and continue through the marginal notches to form faint median grooves on the petals; about one-half the distance to the margin ambulacral lines are thrown off from the main furrows on the actinal surface, which extend to the upper surface as sutural lines between the ambulacral and interambulacral plates. Periproct inframarginal, and placed about its own diameter from the edge of the test. Tuberculation consists of small, serobicular tubercles crowded together over both surfaces. Related forms.—This form may be distinguished by its markedly narrow petals, thick test, and small mouth; these characters separate it from Astrodapsis arnoldi arnoldi (Pack), and from A. major Kew, which seem to be the most closely allied species. 88 Umversity of California Publications in Geology [Vou.12 Geologic horizon—Lower Etchegoin (Jacalitos) formation, Lower Pliocene. Associated with Astrodapsis arnoldi arnoldi (Pack) and Astrodapsts arnoldi var. depressus Kew. Localities —Coalinga district, Fresno County, California, Univ. Calif. locs. 2969 and 2973. ASTRODAPSIS ARNOLDI, subsp. PELTOIDES (Anderson and Martin) Plate 15, figures 2a, 2b, 3 Astrodapsis peltoides F. M. Anderson and Bruce Martin. Proe. Calif. Acad. Sei., ser. 8, Geol., vol. 4, 1914, pp. 52-53, pl. 2, fig. 2. Astrodapsis peltoides Nomland. Univ. Calif. Publ. Bull. Dept. Geol., vol. 9, 1916, p. 202 (listed). Holotype.—No. 102 Calif. Acad. Sci. Coll. Pal.; topotype, speci- men, no. 451 Calif. Acad. Sei. Coll. Pal. Size medium. Measurements of holotype: anteroposterior diameter 64.5 mm., transverse diameter 54 mm., greatest height 15.5 mm. Out- hne of test anteroposteriorly suboval to subcireular ; some specimens notched in the ambulacral areas, the degree of notching being greater in the two posterior ones; margins thick, with the upper surface rising immediately to a moderately elevated summit, which is anterior to the center of the test and on the odd anterior ambulacral area. Apical system central; small and flush with the general surface of the test, but depressed below the highest points on the petals. Broad, deep grooves are present in the interambulacral areas, with smaller ones in the ambulacral areas along the outer sides of the petals. Ambulacra wide at the margin, the interambulcra being about one-third the width of the ambulacra ; ambulacra petaloid. Petals usually narrow but some- what variable in width; inner rows of nearly rounded pores diverge but httle from the apical system, but on reaching their full extent continue in approximately parallel lines until within about one-fourth the distance from the margin, when they diverge slightly to the edge of the test; outer rows of pores diverge considerably at first and then converge slightly and again diverge, the two rows of pores coming close together when near the edge of the test. Lach poriferous zone equal to about one-third to one-half the width of the interporiferous area. Petals more or less elevated, especially near the apical system ; usually of the same width, though the odd anterior one may be slightly narrower and the anterior pair somewhat wider than those of the bivium. Inferior surface concave; peristome small, sunken, and 1920] Kew: Cretaceous and Cenozoic Echinoidea 89 subcireular in outline. Ambulacral furrows well marked, straight, and continuing over the upper surface, in weathered specimens, as sutural lines. Tubercles small, scrobicular, perforated, numerous, and equally distributed on both surfaces of the test. This species shows a great variety of forms from the same locality. These variations include individuals with margins varying from quite thin to very thick, and from a highly elevated to a depressed test ; the petals also vary in their elevation and in width. In as much as gradations can be found between the extremes of the variations all the forms have been included under a single subspecies. Related forms.—F rom Astrodapsis major Kew, to which it is closely allied, A. arnoldi peltoides differs in possessing prominent grooves in the ambulacral areas along the margins of the petals; in that the petals are usually narrower, and the interambulacral depressions are in most specimens not so deep. It can be distinguished from A. arnoldi arnoldi (Pack) as being more strongly elliptical in marginal outline ; in that the actinal surface shows a greater degree of concavity, and in that the petals are usually narrower. It differs from A. jacalito- sensis Arnold in having deep interambulacral grooves. From A. arnold crassus Kew it is distinguished by having a smaller peristome, and usually a more elongate marginal outline; from A. arnoldi var. fres- noensis Kew, in having a more elongate outline and wider petals. A. arnoldi spatiosus Kew may be separated by its extremely wide petals, greatly depressed test, and less strongly elevated petals. Geologic horizon.—Lower Etchegoin (Jacalitos) formation, Lower Pliocene. Associated with Dendraster gibbsw (Rémond). Localities —Holotype from Trophon zone, at head of Zapato Chino Creek, Coalinga district, Fresno County, California, Calif. Acad. Sci. Coll. loc. 293. ASTRODAPSIS ARNOLDI SPATIOSUS, Kew, n. subsp. Plate 22, figures 2a, 2b Holotype—No. 11041 Univ. Calif. Coll. Invert. Pal. Test large. Measurements of holotype: anteroposterior diameter 75 mm., transverse diameter 69 mm., greatest height 14.5 mm. Out- line subcireular, tending to be slightly pentagonal. Margin notched indistinctly in the posterior ambulacral areas and in the odd posterior interambulacral area, rounded and thickened. Upper surface greatly depressed, gently arching to the summit, which is anterior to the 90 University of California Publications in Geology [Vow. 12 center of the test and situated on the odd anterior petal. Apical system small and placed very slightly to the posterior of the center of the test. Ambulacra much wider than the interambulacra, the latter being about five-eighths the width of the ambulacra. Petals markedly broad, wide open, and extending to the edge of the test. Odd anterior petal somewhat narrower than the paired petals. Both the inner and outer rows of pores diverge for about one-third their length, converge until about three-fourths the distance to the margin, and then again diverge to the edge of the test; the divergence of the outer rows slightly greater than that of the inner rows, and the poriferous areas gradually narrowing until the two rows are practically united at the margin. Interporiferous areas exceptionally broad, being about three and a-half times the width of each poriferous area. Rows of pores in the odd anterior petal diverge to their maximum, and then continue in nearly parallel lines to the margin, converging but little; both the poriferous area and interporiferous area narrower than in the paired petals; interporiferous area four times the width of each porif- erous area. Abactinal surface of the interambulaecra characterized by broad, deep depressions extending from the apical system to the ambitus. Indistinet, broad grooves are present along the margins of the petals. Inferior surface shghtly concave. In the single specimen at hand the under side is imperfectly exposed. No ambulacral fur- rows are shown, but branching lines are present which pass to the abactinal side and form a median ridge on the petals and sutural lines between the ambulacral and interambulacral areas. Periproct rela- tively small and inframarginal; situated about its own diameter from the edge of the test. Tuberculation consists of well defined secrobic- ular tubercles of fairly large and uniform size over both surfaces. Related forms—This form may be easily distinguished from all other similar types by its markedly wide petals, greatly depressed test with thickened margin, and apparent lack of ambulacral furrows; if present they are not well developed. It closely resembles Astro- dapsis antiselli Conrad and other forms of the Upper San Pablo group (Santa Margarita), but may be separated by its broad, flattened test and more prominent interambulacral grooves. Geologic horizon Lower Etchegoin (Jacalitos) formation, Lower Pliocene. Locality —Near Standard Oil Company’s well ‘‘Powell No. 1,” Sargent Canyon, east side of Salinas Valley, Priest Valley quadrangle, California (Standard Oil Co. loc. 41), Univ. Calif. loe. 3572. 1920] Kew: Cretaceous and Cenozoic Echinoidea 91 ASTRODAPSIS BREWERIANUS (Rémond) Plate 18, figures 5a, 5b, 5c Echinarachnius brewerianus Rémond. Proe. Calif. Acad. Sei., vol. 3, 1863- 67, p. 53. Echinarachnius brewerianus. Meek, Smithson. Mise. Coll., vol. 7, no. 183, 1864, p. 2. Echinarachnius brewerianus. Gabb, Geol. Surv. Calif., Pal. vol. 2, 1869, pp. 36, 109, pl. 12, figs. 65, 65a. Echinarachnius brewerianus. Cooper, Cat. Calif. Fossils: Seventh Rept., State Mineralogist, 1888, p. 271. Clypeaster ? (Echinarachnius) brewerianus. Merriam, Univ. Calif. Publ. Bull. Dept. Geol., vol. 2, 1898, pp. 109, 118. Clypeaster brewerianus. Merriam, Proc. Calif. Acad. Sci., ser. 3, Geol., vol. 1, 1899, p. 166, pl. 21, fig. 2. Astrodapsis brewerianus. Stefanini, Boll. Soc. geol. ital, vol. 30, 1911, p. 702. Clypeaster brewerianus. Clark and Twitchell, U. 8. Geol. Surv. Mon., vol. 54, 1915, p. 210, pl. 96, figs. 2a—2e, 3. Scutella breweriana. B. L. Clark, Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, 1915, pp. 409, 412, 436 (listed). Neotype.—(Merriam) No. 11016 Univ. Calif. Coll. Invert. Pal. Test rather small. Measurements of specimen no. 11016: antero- posterior diameter 27.6 mm., transverse diameter 24.5 mm., greatest height 5 mm. Outline subcireular to suboval, margin thickened, rounded, and somewhat broadly notched in the posterior ambulacral areas. Apical system central. Abactinal surface depressed, shghtly convex, rising regularly to a low, flattened apex, which is situated on the odd anterior petal near its base. Ambulacral areas wider through- out than the interambulacral areas. Ambulacra petaloid ; petals broad, flush with the surface of the test, and extending nearly to the margin; inner rows of rounded pores diverging widely for one-half the distance to the margin, then continuing in nearly parallel lines to the edge of the test; outer rows of elongate pores diverge to a greater degree at first and then converge until close to the inner rows, where they become rounded, continuing to the ambitus; pores conjugate. Inter- poriferous areas wide, being from three to four times the width of the poriferous areas. Madreporie area small and pentagonal in shape, with large, round genital pores in each corner except the odd posterior one. Actinal surface flat near the margin, concave near the peristome. Ambulacral furrows seldom seen, but when present are broad, straight, and extend nearly to the margin. In one specimen faint branching lines were given off about two-thirds the distance to the edge. Peri- 92 University of California Publications in Geology [Vow 12 stome central, round, and slightly depressed. Periproct round, large, and inframarginal, nearly marginal. Test covered with small tubercles of nearly the same size on both surfaces which have sunken scrobicules. Internal structure consists of radial partitions extending from the margin for about one-half the distance toward the center, and con- tinuing as ridges on the floor to the perignathie girdle. No concentric ridges appear to be present. Related forms.—Although Astrodapsis brewerianus resembles the form A. cierboensis (Kew), it may be distinguished by the narrower petals, absence of interambulacral depressions, very indistinct or no ambulacral furrows, a relatively more elevated test, and petals which are never raised. Geologic horizon.—Briones formation, or Astrodapsis brewerianus beds, which lie conformably below the San Pablo group, Upper Mio- cene, and, with a probable unconformity, above the Monterey group, Middle Miocene. Localities —Walnut Creek, Gregory Ranch (?), Contra Costa County, California (figured specimen, J. C. Merriam, 1899); San Pablo Bay, Contra Costa County; Western Pacific R. R. cut, Verona, Pleasanton quadrangle, California (Leland Stanford Jr. Univ. Coll.), ASTRODAPSIS BREWERIANUS DIABLOENSIS Kew, n. var. Plate 13, figure 6 Holotype.—No. 113835 Univ. Calif. Coll. Invert. Pal. This variety differs from Astrodapsis brewerianus (Rémond) in that the petaliferous portions of the ambulacra are elevated; that the test grows to be somewhat larger, and the outline is shghtly more elongate. All gradations may be found between those having raised petals and those having petals flush with the surface of the test. These are found associated together. Related forms.—It differs from Astrodapsis cierboensis (Kew) in that the petals are narrower and the margin relatively thinner. From Astrodapsis tumidus Rémond it may be separated by the lack of inter- ambulacral depressions, in that the ambulacral furrows are not so well developed, and the petals usually are not so highly elevated. Geologic horizon.—Astrodapsis brewerianus zone, Briones forma- tion, Middle Miocene. Associated with EXPLANATION OF PLATE 30 Figures approximately natural size. Fig. 1. Dendraster diegoensis venturaensis Kew, n. subsp. Holotype, speci- men 11351, Univ. Calif. Coll. Invert. Pal. Lower surface of test. Santa Barbara County, Calif. Upper Fernando formation, Upper Pliocene. Fig. 2a. Dendraster diegoensis diegoensis Kew, n. subsp. Holotype, specimen 12257, Univ. Calif. Coll. Invert. Pal. Lateral surface of test. Pacific Beach, San Diego County, Calif. San Diego formation, Upper Pliocene. Fig. 2b. Dendraster diegoensis diegoensis Kew, n.subsp. Same specimen. | Lower surface of test. [212] UNING CAEIFS “RUBE IBULE: DEPT. GEOL; LKEW ] VOEr 12) RPE. so EXPLANATION OF PLATE 31 Figures approximately natural size. Fig. la. Dendraster excentricus (Eschscholtz). Specimen 12163, Univ. Calif. Coll. Invert. Pal. Upper surface of test. Recent. Fig. 1b. Dendraster excentricus (Eschscholtz). Same specimen. Lateral sur- face of test. Recent. Fig. le. Dendraster eacentricus (Eschscholtz). Same specimen. Lower sur- face of test. Recent. [ 214] UNIV, CALIF, PUBL. BULL. DEPT. GEOL. LSEWS| VOL 2 Pin ea Pp Lv} ‘ Ren, i, 1 - i) a { ntl & F ’ . - — 7 iM ‘ EXPLANATION OF PLATE 32 Figures approximately natural size. Fig. 1. Dendraster excentricus (Eschscholtz). Specimen 12164, Univ. Calif. Coll. Invert. Pal. Upper surface of test, showing variation in petals. Recent. Fig. 2. Dendraster excentricus (Eschscholtz). Specimen 12165, Univ. Calif. Coll. Invert. Pal. Upper surface of test, showing variation in petals. Recent. [ 216 ] UNIV. CALIF. PUBL, BULL. DEPT. GEOL, DSEWINVOE wie) ek, Ge Ga EXPLANATION OF PLATE 33 Figures approximately natural size. Fig. la. Dendraster pacificus Kew, u.sp. Cotype, specimen 448, Calif. Acad. Sei. Coll. Pal. Upper surface of test. Pacific Beach, San Diego County, Calif. San Diego formation, Upper Pliocene. Fig. 1b. Dendraster pacificus Kew, n.sp. Specimen 448. Lower surface of test. Fig. le. Dendraster pacificus Kew, n.sp. Cotype specimen 11340, Univ. Calif. Coll. Invert. Pal. Lateral surface of test. Cedros Island, Lower California, Upper Pliocene(?). ; Fig. 2a. Dendraster (Calaster) oregonensis (W. B. Clark). Specimen 449, Calif. Acad. Sci. Coll. Pal. Upper surface of test. Fossil Point, Coos Bay, Oregon. Merced formation, Upper Pliocene. Fig. 2b. Dendraster (Calaster) oregonensis (W. B. Clark). Specimen +450, Calif. Acad. Sci. Coll. Pal. Lower surface of test. Same locality. Fig. 3a. Dendraster (Calaster) oregonensis gibbosus Kew, n.var. Cotype, specimen 11885, Univ. Calif. Coll. Invert. Pal. Upper surface of test. Near Shively, Humboldt County, Calif., Univ. Calif. loc. 1881. Wildeat series, Upper Pliocene. Fig. 3b. Dendraster (Calaster) oregonensis gibbosus Kew, n. var. Cotype, specimen 11386, Univ. Calif. Coll. Invert. Pal. Lower surface of test. Same locality. Fig. 3c. Dendraster (Calaster) oregonensis gibbosus Kew, n. var. Specimen 11386. Lateral surface of test. [ 218 } UNIV, CALIF. PUBL, BUELL, (DEPT. GEOL. BREW IRVOE 2 Rie. ss & \ : EXPLANATION OF PLATE 34 Figures approximately natural size. Fig. la. Dendraster (Calaster) oregonensis major Kew, n. var. Cotype, speci- men 11044, Univ. Calif. Coll. Invert. Pal. Upper surface of test. Hel River, Humboldt County, Calif., Univ. Calif. loc. 1876. Wildcat series, Upper Pliocene. Fig. 1b. Dendraster (Calaster) oregonensis major Kew, n. var. Cotype, speci- men 11352, Univ. Calif. Coll. Invert. Pal. Lateral surface of test. Eel River, Humboldt County, Calif., Univ. Calif. loc. 71. Wildcat series, Upper Pliocene. Fig. le. Dendraster (Calaster) oregonensis major Kew, n.var. Specimen 11352. Lower surface of test. [ 220] UNIV. CALIF, PUBL. BULL. DEPT. GEOL. [KEW] VOL. 12, PL. 34 rs EXPLANATION OF PLATE 35 Figures approximately natural size. Fig. la. Dendraster (Calaster) interlineatus (Stimpson). Neotype, speci- men 113538, Univ. Calif. Coll. Invert. Pal. Upper surface of test. Seven mile Beach, San Francisco Peninsula, Calif., Univ. Calif. loc. 1726. Lower Merced formation, Upper Pliocene. Fig. 1b. Dendraster (Calaster) interlineatus (Stimpson). Same specimen. Lateral surface of test. [ 222 } UNIV; (CALIF. -PUBEY BULE. DERT: GEOL, LKEW [VOLe 2 RE 35 SO eel ae EXPLANATION OF PLATE 36 Figures approximately natural size. Fig. 1. Hncope tenuis Kew. Cotype, specimen 10050, Univ. Calif. Coll. Invert Pal. Upper surface of test. Coyote Mountain, Imperial County, Calif., Univ. Calif. loc. 2064. Lower division of Carrizo Creek beds, Pliocene. Fig. 2a. Dendraster ashleyi ynezensis Kew, n. var. Holotype, specimen 11334, Uniy. Calif. Coll. Invert. Pal. Upper surface of test. Redrock Cafion, Santa Ynez River District, Santa Barbara County, Calif., Univ. Calif. loc. 3128.. Upper part of Fernando formation, Upper Pliocene. Fig. 2b. Dendraster ashleyi ynezensis Kew, n. var. Specimen 11334, Univ. Calif. Coll. Invert. Pal. Lateral surface of test. Redrock Cafion, Santa Ynez River District, Santa Barbara County, Calif., Univ. Calif. loe. 2259. Upper part of Fernando formation, Upper Pliocene. [ 224] | 36 Lea 2h KEW] VOL. CALIF. PUBL, BULL. DEPT. GEOL. UNIV. * . trek “ #,: wes : * . z . dk EXPLANATION OF PLATE 37 Figures approximately natural size. Fig. la. Encope tenuis Kew. Cotype, specimen 10051, Univ. Calif. Coll. Invert. Pal. Lower surface of test. Coyote Mountain, Imperial County, Calif., Univ. Calif. loe. 2064. Lower Division of Carrizo Creek beds, Pliocene. Fig. 1b. Encope tenuis Kew. Specimen 10050. Lateral surface of test. [ 226 ] UNIV CAR US SSUES a DEG ls, [KEW VOLE. We; Rin 37 7 7 r fe a 1 i Thy = n . 5 i = . if p al Bordering as it does on all three of the so-called provinees, viz., the Great Basin, the Pacific Coast, and the Gulf of California, the region occupies a strategic position on the geologic map of California. It is the most southern of the areas from which vertebrate remains have so far been reported from the Pacific slope. The exploration resulted in discovery of many new and interesting species described in the following pages, and in the recognition and 4 Dickerson, R. E., op. cit., p. 259, 1914. 5 Vaughan, F. E. Evidence in San Gorgonio Pass, Riverside County, of a late Pliocene extension of the Gulf of California. Read at the meeting of the Pacific Coast division of the Palaeontological Society in April, 1917. 1921] Prick: Faunas of Bautista Creek and San Timoteo Caron 281 SEF CAINS SSN Mires Fig.1b. Section of United States Geological Survey, San Jacinto Quadrangle sheet, showing the Bautista Creek Badlands. Univ. Calif. localities: (1) no. 3240; (2) no. 3247; (3) no. 3248; ete. See list of localities in text, p. 293. 282 University of California Publications in Geology [ Vou. 12 development of three distinct horizons of the late Tertiary and early Quaternary. The determination of the age of these deposits has been especially important in its bearing on the interpretation of local orogenic history and the date of the final elevation of the northwest portion of the San Jacinto Mountain Range, which cannot have been earler than post-Bautista. The interesting evidence of the fossils is that each of the three new horizons is representative of a faunistic and geographic phase unknown elsewhere. ea a ass Bs Hl lg ri | Kw eae | <7 A Se we: ffm Seni Fig. le. Section of United States Geological Survey, Elsinore Quadrangle sheet, showing San Timoteo and Eden regions and more important Univ. Calif. localities (San Timoteo, single circles, see p. 319; Eden, double circles, see p. 339). Granitie and metamorphic outcroppings occur about Eden Mountain, Mt. Davis, Lamb Dome, and Potrero Creek. Among the more important materials secured are: dentitions illus- trating new transition stages in the evolution of the horse series from early Pliohippus to Equus; the molars of a large Pleistocene tapir, and of a great Pliocene bear more closely resembling Hyaenarctos sivalensis of the Indian Siwalik than any of the two or three previously represented American forms; remains of four types of ground sloth, and of a number of very interesting varieties of the camel group. The three exposures and their faunas are as follows: s alt bs “ser 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 283 I. Bautista CREEK AREA (PLEISTOCENE) The Bautista beds, in which have been found a large Equus some- what resembling that of the Staked Plains, a tapir, a camel, a cervid form resembling Odocoileus, a small species of antelope near Capro- meryx, a neotragocerine-like form, a megalonychid type of ground- sloth, and a rabbit, II. San Timoreo CANon AREA (LATE PLIOCENE) The upper series of deposits, here referred to as the San Timoteo beds, from which has been obtained a fauna containing a very large and a medium size horse of an interesting Pliohippus type approxi- mating Equus, a cervid(?), two camels, a megalonychid ground-sloth, and two tortoises. III. Epen Area (Upper Division or LowEr PLIOCENE) A lower series of deposits referred to as the Eden beds, which has furnished several intensely interesting species of small horse of Plio- hippus form, fragmentary remains of ground-sloths of megalonychid type, of the sabre tooth tiger, and of small species of dogs and cats, a hyaenarctid bear, several large cervid or antelope-like forms, a smaller antelope, two species of peecary, two giant and three or more smaller varieties of camel, a mastodon of Trilophodon type, a species of rabbit, and remains of fish, shells, and wood. A coarse deposit has been noted underlying the Eden in the neigh- borhood of Potrero Creek. It has as yet yielded no determinative material. The immediate aim of the work was originally purely palaeonto- logical, and the geological sketch in the following pages is offered merely as a setting for the description of the faunas, preliminary to the geological mapping of the region. The writer desires to acknowledge particularly his indebtedness to Professor John C. Merriam for much friendly advice and invaluable assistance in critical determinations. He wishes also to express his appreciation of the interest shown by Dr. John P. Buwalda in the geological aspect of the problem, and of the great aid rendered by Dr. Chester Stock in assisting in making comparisons with specimens in the University collections, as for his determination of the ground-sloth remains. He would as_ well acknowledge the painstaking attention of Dr. Stock, Mr. E. L. Furlong, and Miss H. E. Ripley to the manuscript, while in press. 284 University of California Publications in Geology [Vou. 12 The drawings® were made, with great care, by Miss Frieda Leud- demann under the personal supervision of the writer. The writer would acknowledge the many kindnesses and good will of the owners of the properties where the explorations have taken place, especially Mr. Blackburn, of Hemet, the proprietor of Eden, Mr. Weaver, and many others. He further wishes to draw attention to the enthusiastic codperation of his field assistant, Mr. Joseph Rak, to whose keen interest and long training as miner and prospector the suecess in the field was largely due. HISTORICAL Palaeontologically up to the time of the present investigation the two regions were virgin territory and unmentioned in the literature. Geologically the San Timoteo Badlands had been interestingly dis- cussed by Dr. W. C. Mendenhall’ in his study of the water supply of the San Bernardino Valley, in which he points to their great economic importance in forming the impervious southern wall of a natural supply basin. While no vertebrate fossils had been reported from the San Timoteo area at the time of writing, nor previous to the present work, an interesting specimen had been returned from the Bautista deposit. This, the posterior portion of the mandible of a fossil horse containing P; and Ms, had been unearthed in the fall of 1916, by Mr. Blackburn, on his fruit ranch, Bautista Creek, Hemet, and sent to the University of California. At the University it had come into the possession of Professor John C. Merriam and had suggested the desirability of an exploration of the neighborhood. At the midwinter meeting of the Pacific Coast section of the Paleontological Society held in April, 1917, the writer read a short report on the work he was then carrying on in this Bautista deposit. 6 The sketches were first laid off according to the greatest transverse and anteroposterior measurements; and in the ease of shaded drawings these measure- ments were used as the basis on which to make the slight necessary foreshorten- ing. In the case of the sketches of the occlusal views of the horse teeth all were drawn in the actual plane of the triturating surfaces. The tooth measurements given in the schedules, on the other hand, were taken perpendicular to the tooth axis, and always exclusive of the cement. The anteroposterior diameter is the greatest distance between the anterior and posterior tooth facets in both the upper and the lower teeth. The transverse diameter of the upper equine teeth is the greatest distance between the outer extent of the mesostyle and the inner wall of the protocone; the transverse diameter of the lower teeth is the greatest distance between the inner extent of the metastylid and the outer wall of the protoconid. 7 Hydrology of San Bernardino Valley, California. U. 8. Geol. Surv., Water Supply Paper no. 142, 1905. 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 285 HISTORY OF THE REGIONS California during Pliocene time was very much as today. The land was gradually rising, and on the submerged narrow coastal plain was laid down a great thickness of marine beds. Fortunately for the record of life forms of the time this elevation was not uniform, and through local subsidence older Miocene valleys in the Coast Ranges, sections of the Great Valley, and basins such as that then existing in the region northwest of San Jacinto were filled with land laid sediments.° In the neighborhood of Eden these Pliocene sediments covered the earlier and coarser deposits, such as now seen along Potrero Creek, and buried to a depth of many feet any rough island-like bosses of the older rock that rose above the uneven basin floor, like the present Eden monadnock. The materials of the deposition were fine surface sands and muds derived from the erosion of the granitic and metamorphic rocks of a near-by highland terrane. They were of unassorted finer grades of alluvial material, that point to a development under arid conditions where disintegration was in advance of weathering.1°. They were doubtless spread out as silt over what was then a region of shallow brackish lakes and plains. It was an interesting assemblage that then roamed the Eden wilds. Grazing over the open stretches were great droves of fleet, ight-limbed horses, half a dozen or more species of camels, bands of large and of small antelope, and herds of deer. Within the edge of the serub might have been seen pigs and larger boar, or an occasional herd of curious, four-tusked proboscideans. In the forests lived sabre-toothed cats, ground-sloths, wolves, and huge bears larger than the largest Kadiak of today. In richness and variety this extinct American fauna must have compared well with the existing African, the bovid antelopes in their multiplicity of form and the herds of zebra of present Africa recalling 8 Smith, J. P. Geological History of California. Science, n.s., vol. 30, p. 346, 1909. 9 The length of the Cenozoic Era, the Age of Mammals, has been placed, through computations based on the total thickness of sedimentary rocks compared with present ratios of accumulation, at about three million years (Dana, 1874, Walcott, 1893). The last sixth of this period, or 500,000 years, is accepted as the length of the Quaternary (see Osborn, ‘‘The Age of Mammals’’ and ‘‘Men of the Old Stone Age’’). According to the same reasoning the duration of the Pliocene would have been from 750,000 to 1,000,000 years, which would place Eden age, late Lower Pliocene, in the neighborhood of 1,000,000 B.c. 10 The analysis of rock specimens was very kindly carried out for the writer by Professor G. D. Louderback. 286 University of California Publications in Geology [ VoL. 12 to a marked degree the camel and equine hosts of our Pliocene of long ago. Moreover, the conditions of this Pliocene were probably very similar to those extant throughout a vast expanse of the desert- encircled belt of the eastern highland of present Africa, where a slight change in altitude with accompanying increase or decrease in humidity, temperature, and vegetation, again and again witnesses the strangest and most marked faunistic change. It may well be that some of the gaps that seem to separate our few known Plocene assemblages are the result of such local distribution rather than of great lapse of time. At length local stream activity, stimulated through the gradual elevation of the San Jacinto region, brought the Eden sedimentary stage to an end, and caused its deposits to undergo a period of erosion. This stream rejuvenation may have been due in part to an associated subsidence of adjoming areas, as bedrock, which must in compara- tively recent times have been subjected to aérial action, occurs today only at some thousands of feet beneath the floors of adjacent valleys. At the close of the Eden erosion stage another but coarser series of sediments were laid down, those of the San Timoteo beds. These covered the finer Eden to a great depth. A striking character of this later deposition is the banded appearance of the strata, due to recurring coarser and finer materials, which suggest either alternations of high and low relief or climatic change. The fauna of the time in comparison to that of the Eden is little known, but was evidently of most instructive transitional stage. The small and earlier types of Pliohippus are replaced by more advanced horses; a large horse, and a smaller animal that to a pronounced degree resemble the more pro- eressive horses of the older Eden race. Ground-sloths, several camels, antelope, and great tortoises are all represented in this fauna. The deposits of the Bautista Badlands, lying to the southwest of Eden, are of later date. They were evidently accumulated in part in a playa-like lake as a series of fine, worked-over fanglomerates and clays derived from the low highlands of the immediate north and east. The late Pliocene inhabitants of San Timoteo had in their turn passed away, for in this great deposit are seen collected the remains of a new fauna, though again of mixed forest- and plains-grazing type. The horse is fully as advanced as that which occurs in the Rancho La Brea asphalt deposits, and perhaps with the associated antelope, deer, camels, and ground-sloth represents even a shghtly later stage than that indicated by the Rancho La Brea fauna. A CorrELATION OF THE EpEN, SAN TimotTno, Bautista, AND CEerTAIN OTHER Horizons. Pacific Coast Province Bautista Creek (bb) Equus bautistensis, n. sp. San TIMOTEO i Pliohippus francescana, n. sp. Pliohippus francescana minor, n. subsp. TipEn (a) Pliohippus osborni, n. sp. Pliohippus osborni, sp. A, n. subsp. Pliohippus edensis, n. sp. Pliohippus edensis, subform A, Pliohippus, spectans-like Pliohippus edensis, subform B, Pliohippus, indet. sp. FOLDER 1. EquinE CHEernx Thera (sep P. 287) (Relative stages indicated by letters, a, b, c, ctc.) Great Basin Province CALIFORNIA, OREGON, AND Ipawo (c) Equus pacificus Leidy Equus idahoensis Merriam ‘ 4 Rancuo La Brea (d) Equus occidentalis Leidy Upper ErcuHEcorn (f) Pliohippus proversus Merriam Mrppie Eircunaorn (d) RATTLESNAKE (c), and THOUSAND CrEEK ()) (c) Pliohippus, near fair- banski Merriam (b) Pliohippus fairbanksi Merriam (c) Pliohippus spectans Cope (c) Hipparion, near occi- dentale Leidy (c) Hipparion sinclairi Pliohippus coalingensis Mer- riam BASED ON THE CHARACTERS OF Eastern and Atlantic Area (a) Equus complicatus Leidy Equus fraternus Leidy Great Plains Province (b) Loup River, NEBRASKA Equus excelsus Leidy Equus niobarensis Hay STAKED PuaIns, TEXAS Equus scotti Gidley Buanco, Texas Pliohippus simplicidens (Cope) Pliohippus cumminsii (Cope) SNAKE Creek, NEBRASKA (ce) Pliohippus ef. mirabilis Leidy Pliohippus leidyanus Osborn Hipparion cf. occidentale Leidy Hipparion gratum Leidy Hipparion ef. affine Leidy Protohippus cf. placidus Leidy Protohippus near perditus Leidy Pliohippus fairbanski Merriam : Wortman (c) Hipparion, near anthonyi Lowrr Ercurcoin Merriam Pliohippus, sp. (b) Neohipparion leptode Protohippus tehonensis Mer- Merriam riam Hipparion gratum tehonense Ricarpo Merriam Pliohippus tantalus Merriam Hipparion, near molle Mer- riam Pliohippus, near mirabilis Leidy Hipparion mohavense Mer- riam Hipparion mohavense callo- donte Merriam 4s itn OTR of. 7 - \nbiye Bi depart ! ‘ *- atc cen tho ERS aaGhe MPD @e HONDA. raed A a ne eee ‘a slight =. > ' uma bene ‘F i Seria AeA aaa. 7 : A lial starr Oo rrrua ks : (da) prota on VPLE aly beroat Hepel ite Wa eke rlerd ie ; 4 LA: ~ * ay { uu 5 = H a serie raya OTE if WAC. huseoorrn enaqaidont ¢ ig 2 ij. i wetl euqetont 5 : j we Seth erie ME T10n5 t Le ut rf a “at a. ret er at {¥ { ode 7 BUY idole; . 7 OU AS oe irda) 3 igo we ear gti, a ected BUratabtitet we! O- ; ine eiesoha Siealtos neo ra te is | A sf osfil-ennisoge eanptdedt = cripldie eaacsbe enrisouay is : : = i y : . F x A wae doth ange : x Lt ¥ yt fe? 3 god 4 iT } > ; fa : cae tae | 10 Ki iv pes Fi ‘ {ti atthe “He a as lowe, ne } HN ULeE 4 . a 5 ‘ * 7 s 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 287 The last stage here recognized was finally brought to a close by a general elevation which, according to the fauna, took place not earlier than mid-Pleistocene time. It lifted the lower San Bernardino and San Jacinto ranges to their present great elevation, and raised and tilted the sedimentary beds of the adjacent basins whose eroded remnants today form the Badlands of the San Timoteo Canon and of Bautista Creek. CORRELATION Eden.—The Pliocene has been the least known of American Ter- tiary horizons. Only in recent years has a representative fauna been obtained, and the line of division between it and the Miocene can as yet be but loosely drawn. In a recent review Professor J. C. Merriam™ has grouped the most important Pliocene land-laid deposits according to the topographical features of the Cenozoic Epoch as follows: (1) the Eastern Coast area, represented principally by the Florida Alachua; (2) the Western Plains region, including the early Repubh- ean River deposits of northwestern Kansas, the Snake Creek of west- ern Nebraska, and the later Blanco of northwestern Texas; (3) the Great Basin Province, represented by the Ricardo of the Mohave Desert, the Thousand Creek of Nevada, and the Rattlesnake of Oregon; (4) the Pacifie Coast Province, including the Chanac-Etchegoin, and the Pinole Tuff-Orinda. The known deposits of this last province are now increased by the addition of the Eden (see map, fig. 1a). The fauna of the Republican River and the Alachua is believed, because of the large proportion of characteristic Miocene types, to lie near the border line between the Miocene and Pliocene. The presence of Miocene, together with a host of more modern forms, in the great Snake Creek aggregation suggests the interesting possibility that the same may represent more than one stage of Tertiary hfe. All of the more advaneed forms of this great assemblage are recognized in allied species in the Thousand Creek, the Chanac-Etchegoin, the Rattle- snake, and the Eden formations, in all of which the oreodonts and Hypohippus forms occurring in the Republican River and the Ricardo, and the more primitive of the forms occurring in the Snake Creek are conspicuous by their absence. 11 Relationship of Pliocene Mammalian Fauna from the Pacifie Coast and Great Basin Provinces of North America. Univ. Calif. Publ., Bull. Dept. Geol., vol. 10, pp. 421-443, 1917. 288 University of California Publications in Geology [ Vou. 12 A comparison of these five interesting and somewhat similar faunas of the Eden, Rattlesnake, Chanac-Etchegoin, Thousand Creek, and advanced stage of the Snake Creek shows: (1): Prosthennops. The Eden species is more progressive than the Snake Creek, and perhaps less so than the Thousand Creek, while a larger peccary species from the Eden, more closely resembling Platygonus, suggests a similar form known only from the Blanco. (2) Procamelus and Pliauchemia. Pliauchenia merriami of the Eden is of more advanced type than any of the evidently earlier Snake Creek camels, which alone are repre- sented in a manner sufficient for comparison. (3) Proboscidea. Re- mains occur in all four horizons, but the material is too scanty for fixed reference. (4) The twisted-horn division of the Antelopinae. Represented in the Thousand Creek and suggested in the Rattlesnake, this is absent from the Snake Creek as from the Etchegoin-Chanae and the Eden. (5) Rhinocerotidae. The Rhinoceroses are as yet unknown from the Eden alone of these mid-Pliocene horizons, though likewise unrecognized in the earlier Ricardo where their presence would be expected. (6) An important difference in the Eden in comparison to these other formations occurs in the absence of Hipparion. (7) Pliohippus. Species are present in all four formations. Among the Eden Pliohippus forms there is one that greatly resembles P. spectans of the Rattlesnake; another of more advanced equine characters than any occurring in the four former horizons; while the Pliohippus mirabilis type of the Snake Creek and of the Ricardo and the P. fair- banski of the Ricardo, Rattlesnake, and perhaps of the Etchegoin and Chanae, are not represented. This presence of an advanced and inter- esting form of Pliohippus among more generalized Pliohippus types, such as P. spectans, and the absence of more primitive equine forms is taken to indicate a relative lateness in the Eden fauna. It is on these advanced characters of the Pliohippus forms, the added evidence of a later stage suggested through the absence of Hipparion, and the general progressive characters of the fauna as a whole that the writer has proposed the correlation of the Eden fauna with those of other Pliocene horizons shown in attached table, in which the correlation of the Ricardo, Etchegoin and Chanac, Rattlesnake, and Snake Creek _ follows that already proposed by Professor Merriam. San Timoteo—The horses of the overlying San Timoteo, as described and discussed at length in the text, are perhaps more like Pliohippus cumminsti and Pliohippus simplicidens (Cope) of the Blanco, which are unfortunately but poorly represented for ee ee a 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 289 comparison, than any one of the other known.forms. They are evidently of more primitive type than such species as Pliohippus proversus Merriam of the Upper Etchegoin and Equus idahoensis Merriam of the probably still later Idaho formation. Bautista.—The tooth pattern of Equus bautistensis suggests a greater degree of specialization than that seen in E. occidentalis of La Brea. The teeth while markedly smaller than the type specimens of E. pacificus and EF. giganteus, are very similar in both size and pattern to the teeth of E. niobarensis of Nebraska and apparently to those of E. scotti of Texas. They are much less specialized than the specimens representing the types of HZ. complicatus and E. fraternus Leidy. PLEISTOCENE FORMATIONS OF THE BAUTISTA CREEK BADLANDS The Bautista Creek Badlands (fig. 16) lie within the foothills of the San Jacinto Mountains some six miles to the southeast of the badlands of the San Timoteo Cafion. They comprise two large, hilly areas divided by the westwardly flowing San Jacinto River. The- more southern area includes the Bautista type locality and stretches six miles southeast between the converging San Jacinto River and Bautista Creek to the igneous wall of the mountainous foothills. At places along this southeastern line of indefinite north and south contact with the basement mass the brush grown sedimentary hills rise to an altitude of 3500 feet. The northern boundary of the Bautista type area and the southern boundary of the second, or Soboban area, is formed by the river. The former unity of both the north and south sedimentary areas is well indicated by the general similarity of the bedding on either bank of the San Jacinto River. A sedimentary remnant, Park Hill, lying immediately to the north- west in the Hemet plain, may belong to the Bautista, and the present isolation may be due to the cutting of the river or its tributaries. The beds forming the Bautista type locality are bounded on the south by the creek of like name and by Rouse’s Creek, which joins it from the southeast. The two streams follow the line of contact between the sedimentary deposits and the basement rock, which is believed to mark a fault. An interesting contact between the formation and the base- ment complex may be seen on the right bank of the San Jacinto River, just west of the mouth of South Fork, where gently north-dipping Bautista sediments rest upon steeply pitching granites (pl. 43, lower 290 Umversity of California Publications in Geology [ Vou. 12 left corner of fig. 1). No clear plane of meeting of basement complex and sedimentary deposit is observed in the wall of Rouse’s Cajon to the southeast, the stream cut, which there follows the line of division, running within the fill of a previously excavated channel. The Soboban portion of the deposit is limited northward by the metamorphies of Claremont and San Jacinto, where the sedimentary beds are faulted down against the side of the mountain. In places they lie directly beneath great, slickensided faces. At least two fault lines occur: that of the main northwest and southeast Claremont fault, mentioned below in conjunction with the hypothetical southern Badland-Eden Mountain line; and a fault running northeast that cuts the first at an angle of 45 degrees and forms the southeast corner of Mount Claremont. The sedimentary beds of the northeast corner of the Sobodan exposure in the immediate vicinity of the fault dip away from the granites, while those a short distance south, along the plane of contact, dip in the opposite direction. This northern dip has again been noted in the poorly stratified exposure of the river bank, and is believed to be the one general to this part of the formation. The structure of the loosely piled deposit, however, shows the results of many violent stresses and is far from uniform. An apparent unconformity in a cliff of coarse, slightly indurated sand at the mouth of Poppet Creek is believed to represent merely an exceptional example of the general disturbance. At this point a large section dipping 15 degrees to the south-southwest apparently rests on another that dips 75 degrees to the south-southeast. The principal exposure of the Bautista in which collections were made by the writer was the southeastern third of the more southern area, and is known as the type locality (pl. 44, figs. 1,2). It is bounded on the south by Bautista Creek and on the north by the sedimentary wash of Whittier Canon that roughly parallels the latter at a distance of a mile and a-quarter. It ineludes the whole eastern half of the southern portion of the deposit. The beds le in a twisted and broken fold, whose generalized axis stretches northwest and southeast in line with Park Hill and the so-called Bald Mountain; the dips of the north and south limbs in passing from east to west twist respectively from northeast and southeast to northwest and southwest. The bedding planes, like those of the Soboban exposure, indicate the warping that the whole lightly indurated region has suffered, their continuity being tremendously broken and confused through local faults and slides. A modern and very interesting example of a great slide is to be seen at the northern end of Whittier Cafion, a result of the San Jacinto-Hemet 1921] Frick: Faunas of Bautista Creck and San Timoteo Canon 291 earthquake of Christmas morning, 1900, when a great bend in the hills a mile and a half across gave way and filled the air of the whole countryside with dust clouds. The vertical displacement of some seventy feet is clearly marked in the surrounding walls. Over the tumbled area the old vegetation grows unharmed. A forester’s trail which formerly crossed this area is now forced to a wide detour to the east. The materials of the Bautista deposit are markedly different from those of the San Timoteo to the northwest, in the evenness of the bedding and in the total absence of cobble-bearing strata. Moreover, the minutely classified strata of fine lacustrine sands and lustrous clays which are present in the main central and higher portions of the type loeality are quite unknown in either of the San Timoteo horizons. It is in these clays and fine sands that the best of the Bautista fossil material has been secured. ‘Another difference between the western and eastern areas is the frequent occurrence in the Bautista of con- centric sections of caleareous pipes, which range in size from the diameter of a twig to that of a large oak, and point to the former prevalence of hot springs. Mica and gypsum are also more common in the Bautista than in the San Timoteo or the Eden. The surface of the ground itself shows a further difference, the coarse hard litter of quartz gravel and granite cobbles of the San Timoteo being replaced by the disintegrating remains of interstratified calcareous layers. Conditions suggest that: (1) these great southwestern deposits were derived from erosion of a neighboring highland, in part through a process of weathering such as that now going on in the interesting granitic faces at the head of Rouse’s Cafion, which are indistinguish- able at short distances from the whiter sand bluffs of the sedimentary areas; (2) the materials of erosion were accumulated on an old land surface crossing the basement complex, and were later raised and faulted down, as indicated by the general plane of contact between the north and south boundaries of the sediments and the granites, a3 well as by such visible points of deeper meeting as that at the mouth of South Fork. OCCURRENCE The present day surface of the Bautista deposits offers a con- siderably richer field for the collection of fossils than either the San Timoteo or the Eden. Mr. Blackburn found the original equine mandible within a recently burnt-over area at the mid-southern extremity of the typical exposure, where careful examination of the 292 University of California Publications in Geology [Vou 12 tép soil and the washes later revealed further interesting material. Fossils have been found in place in the following sediments: 1. Nodular, indurated, sandy clays: In tracing the source of fragments of bone and digging within the top soil small pockets have been located containing nodular sandy clay rock, reddish tinged on fracture, and holding associated skeletal remains. The rocks lay in a stratum of fine sandy, micaceous clay, which farther down contained less clay and more sand, and at slightly lower levels passed into grayer and coarser sand. At one locality (3242) three such pockets occurred within a radius of twenty feet, containing equine limb bones that had apparently belonged to the same individual. The manner of occur- rence, and the fact that certain separated nodules contained parts of the same bones, the broken silicified edges of the bones matching when brought together, evidence that considerable movement has occurred in the deposit since the time of deposition and nodularization. 2. Thick deposits of black clay: Within the south-central part of the Bautista district, at twenty-five hundred feet elevation, are con- siderable northeast-dipping deposits of lustrous black, micaceous clays alternating with fine sands. Similar beds have been noted dipping to the southwest in a ravine eight hundred feet lower down. At one place at the higher elevation these clays were found to contain many bone fragments, and here (locality 3243) much of the most representa- tive Bautista material was obtained. The operation was carried on in a four-foot stratum that was interbedded between layers of coarse, gray sand. Above the latter was another layer of the clay a foot in thickness, and this was overlain by coarse, yellowish sand, which higher up became grayer and was mixed with quartz pebbles. The fossils though comparatively plentiful were soft, and were minutely broken from the gradual movement evidenced in the network of cracks that ran throughout the entire deposit. 3. Fine and coarse, non-indurated sands: Fossils were found to a somewhat less extent in the non-indurated sand beneath these clays. Exposures of micaceous, fine, greenish sand, rather frequent through- out the southwestern portions of the Bautista, have also yielded con- siderable material, especially in the neighborhood of calcareous ledges. The original equine jaw fragment was found by Mr. Blackburn in such a formation (locality 3240). 4. Exceptionally, in fine, brown-gray, micaceous sandstone: A piece of this rock picked up at the mouth of one of the cafions yielded a well preserved fragment of the mandible and teeth of a small artio- dactyl. 1921] Frick: Faunas of Bautista Creck and San Timoteo Canon 293 Bautista Fossit Locatitres WHERE More Important SPECIMENS WERE COLLECTED All localities, unless otherwise stated, are in T. 5 8, R. 1 E., San Bernardino B. L. and M., San Jacinto Quadrangle, U. 8. Geol. Surv. Sheet (fig. 1b) Univ. Calif. loc. Fossil Cafion 3240 SE portion NW 14 of SW 14 of Sec. 26, W side, first small wash on SW side of burnt hills and E of North Cafion; barometric altitude 2200 feet. (fig. 1b, no. 1.) Horse and Deer Pits 3421 S portion NE 14 of SW 14 of Sec. 26, W running ridge E and NE of Fossil Cafion Deer-pit 200 yds.; W and below. Horse- pit. Pedata Pit 3242 S portion NW 14 of SE 4% of Sec. 26, Hog- back on north side, 14 mile up sixth east- erly cafion above mouth of North Canon. Blacksand Station 3243 S portion SW 14 of SW 14 of Sec. 25, 40 ft. cut in ridge corner; barometric altitude 2820 feet. (fig. 1b, no. 3.) Blacksand Top 3244 Ridge directly above and N of station 3243. Slide Region 3245 W portion SE 14 of SE 14 of Sec. 25, 40 ft. cut in ridge corner; barometric altitude 2950 feet. Highest Hill 3246 SE 14 of SW 44 of Sec. 30, T. 5.8, R. 2 E. Meek’s Neighborhood 32474 Small cafion and low ridges in immediate vicinity of old house foundations. (fig. 1b, no. 2.) Whittier Cafion 3247B Mouth of cafion bounding type locality to W and NW. DESCRIPTION OF BAUTISTA PLEISTOCENE FAUNA Lepus, sp. Antilocapra or Neotragoceros, one Megalonyx, sp. or two indet. sp. Camelid Equus bautistensis, n. sp. Odocoileus(?), two or more species Tapirus merriami, n. sp. Capromeryx(?), sp. LEPUS, sp. Material—Two fragments of caleaneum and podial bone, Univ. Calif. Coll. Vert. Pal. no. 23522, Univ. Calif. loc. 3247s. The small specimens give evidence of the presence of a fair-sized rabbit or hare in the Bautista fauna, but are too fragmentary for specific determination. 294 University of Califorma Publications in Geology [ Vou. 12 MEGALONYX?, sp. Material.—The phalanx of a ground-sloth, Univ. Calif. Coll. Vert. Pal. no. 23372 (figs. 1d and le), Univ. Calif. loc. 3243. MEASUREMENTS No. 23372 Greatest anteroposterior length -..........2.--..--..--sce---se-ceeeeee- 54.5 mm, Greatest dorsoventral depth of proximal end ...................... 36 Greatest transverse thickness at middle ..............0..2..22.2.----+ 33.5 The specimen (fig. 1) is of nearly bilateral symmetry ; the proximal articulation consists of two vertical concavities separated by a median ridge, the upper and lower extremities of which are of nearly equal Figs. 1d and le. Megalonyx?, sp. Second phalanx, no. 23372, X %. Fig. 1d, lateral view; fig. le, distal view. Bautista beds, California. size and production ; the convex borders of the distal trochlea describe approximately two-thirds of a circle, the groove of the trochlea is very deep. Remains of both the genera Nothrotherium and Megalonyx oceur in the Pleistocene of Rancho La Brea and in the cave deposits of northern California. Dr. Chester Stock, who kindly has examined the specimen, states that it possibly represents a phalanx of a small megalonychid form. The Bautista specimen is short and slender com- pared to a phalanx from Hawver Cave which has been tentatively referred to Megalonyr. It resembles somewhat phalanx 2, digit 2 of the manus of Mylodon from Rancho La Brea but is smaller. 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 295 CAMELID#?, sp. Material.—The distal portion of a metapodial, no. 23458; a scaphoid, no. 23396; and two phalanges, nos. 23388-23389, all in Univ. Calif. Coll. Vert. Pal. (figs. 2-4); all from Univ. Calif. loe. 3248. The metapodial (fig. 2) has been considerably crushed. It is of medium size, and with the phalanges (fig. 4) and scaphoid (fig. 3) Figs. 2 to 4. Camelid?, sp. Limb elements, X %4. Fig. 2, distal portion of metapodial, no. 23458, anterior view; fig. 8, scaphoid, no. 23396; fig. 4, second phalanx, no. 23388. Bautista beds, California. represents a much smaller form than Camelops of Rancho La Brea. The specimen apparently belongs to an individual of much the same size as that represented by a first phalanx in the Univ. Calif. Coll. (no. 10986) from the San Pablo Pleistocene. MEASUREMENTS No. 23458, diameter of single distal trochlea of metapodial .................. 39.3 mm, No. 23458, length of separation between inner and outer trochlea of ITLEG ATO lila Heewensceewaremeser et ceesteteeer tee svecer costedaahas_22'a0siocsbaanecysciereeen, An sesset tenes 74.8 No. 23388, length of second phalanx ...........-.-------::------ceece-neeeeeeeeseeseeeeeseseees 61.5 No. 23388, diameter of proximal end of second phalanx ....................-.-..- 29.1 296 University of California Publications in Geology [ Vou. 12 ODOCOILEUS?, two or more species Material—(1) A section of a left mandible containing the last cheek-teeth, Univ. Calif. Coll. Vert: Pal. no. 23405 (fig. 5), Univ. Calif. loc. 32474. (2) The proximal half or two-thirds of an antler with burr and prong, no. 23419 (fig. 6), Univ. Calif. loc. 3243. (3) A metatarsus and first phalanx, no. 23452, distal end of first phalanx, no. 23524, and second phalanx, no. 23523 (figs. 7, 8), loc. 3249, (4) A right humerus, associated with portions of the ulna and radius, the meta- carpus, a sesamoid, and parts of the left humerus and ulna-head, the radius and the metacarpus, nos. 23442-23445, nos. 23448-23450 (figs. 9-12b), loc. 3241. A piece of the distal end of a humerus, no. 23526, from vicinity of loc. 3241. (5) An astragalus associated with the distal end of a left tibia, no. 23401 (fig. 14), Univ. Calif, loc. 3247; a right astragalus, same coll., no. 23402, region of Univ. Calif. loc. 3241. (6) The mid-distal end of a larger humerus, no. 23451; the head fragment of a small femur, no. 23781; the head fragment of a medium sized femur, no. 28782; and the portion of a scapula are all referred to this sec- tion. All specimens in Univ. Calif. Coll. Vert. Pal. All Eden localities. Fig. 5. Odocoileus?, sp. Fragment of mandible with Mz and Mz, no. 23405, xX 1. Bautista beds, California. The material indicates the presence of two or more Odocoileus-like species, The lower molars no. 23405 (fig. 5) are comparatively light and low-crowned, and the enamel is considerably crinkled. Two outer buttresses, or styles, are present in Mz; a single style in Ms. The teeth differ from those of Odocoileus hemionus and O. columbiana in the presence of these two outer buttresses in the last molar, as in the development of the single buttress of M5, which though generally ~1921] Frick: Faunas of Bautista Creek and San Timoteo Cation 297 prominent in the premolars of O. hemionus is often absent from the molars of both O. hemionus and O. columbiana. So far as observable the cervid remains from the Pleistocene cave de- posits of California also lack the double buttress of the last molar. The enamel is considerably more erinkled than that of the comparatively lone- crowned O. hemionus, and somewhat more crinkled than in O. coluwmbiana. COMPARATIVE MEASUREMENTS Odocoileus?, O. hemi- O. colum- sp. no. 23405 onus biana Ms, anteroposterior diameter 25.8mm. 23.2 25.2 Mz, transverse diameter ........ 10.3 10.3 8.2 M;, height of crown .............- 9.1 10.6 11 M;, anteroposterior diameter 22.2 20 M;, transverse diameter ........ 9.9 7.2 M;, height of crown .............. 8.4 10.7 The specimen (fig. 6) represents a de- ciduous antler of advanced cervid type. The occurrence is of interest as strongly pointing to the presence of a species near Odocoileus in the Bautista Pleistocene. A metatarsus, no. 23452, is unfortunately somewhat crushed. Though slightly heavier propor- tionately than the metacarpus de- seribed below (fig. 12) it is of a very similar appearance. The phalanges (figs. 7, 8) are more Fig. 6. Odocoileus?, sp. Proximal typically deer-like than antelope- portion of antler, no. 23419, XK %. : : Bautista beds, California. like in form. Figs. 7 and 8. Odocoileus?, sp. Phalanges, X %. Fig. 7, first phalanx, no. 23524; fig. 8, second phalanx, no. 23523. Bautista beds, California. = = = 12b Figs. 9 to 12b. 12a Odocoileus?, sp. Associated limb elements, X 1%. humerus; fig. 10, proximal portion of ulna; figs. lla to 11e, radii; figs. 12a and 12b, metacarpals. Fig. 9, Bautista beds, California. Univ. Calif. Coll. Vert, Pal. nos. 23442-23445 inclusive, and nos. 28448-23450. 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 299 The anterior limb elements (figs. 9-12) suggest a form fully as tall but slighter, and longer-shanked than the modern mule-deer. The metacarpus is of very similar form to the metatarsus described above, and may represent the same species. Compared with the correspond- ing bones of Odocoileus hemionus: (1) the humerus (fig. 9) is slightly shorter and lighter; (2) the radius (fig. 11) is slightly hghter and of about equal length; and (3) the metacarpus (fig. 12) is distinetly longer. Figs 13a to 13c. Cervid or Antilocapra?, sp. Tarsal elements, no. 23403, * 1. Fig. 18a, astragalus, dorsal view; fig. 13b, astragalus and navicular-cuboid, outer view; fig. 13c, navicular-euboid, lateral view. Figs. 14a to 14c. Odocoileus?, sp. Astragalus, reconstruction from nos. 23401, 23402, X 1. Fig. 14a, dorsal view; fig. 14b, lateral view; fig. 14c, ventral view. Bautista beds, California. The two astragali (see reconstruction, figs. 14a—-14c) are consider- ably heavier and of different character from no. 23403 (see above, fig. 13), being strongly cervid throughout in: (1) the groove of the distal end is deep and sharply defined, and the outer condyle of the trochlea broad; (2) the occurrence on either side of the central fossa of a knob which terminates mid-dorsally both condyles of the proximal 300 University of California Publications in Geology [ Vou. 12 trochlea surface, instead of that of the inner side only as in the antelope; and (3) the contour of the outer condyle of the proximal trochlea which is broad and full, while the groove of the wide caleaneal surface is medium and pronounced. CAPROMERYX?, sp. Material.—A small astragalus, and a section of the distal end of an associated metapodial, Univ. Calif. Coll. Vert. Pal. no. 235274 (figs. 15, 16), Univ. Calif. loc. 3245. The astragalus (fig. 15) is considerably broken and worn. It is distinctly smaller than any specimens of Capromeryx minor Taylor 15b Figs. 15a to 16. Capromeryx?, sp. Astragalus and distal end of metapodial, no. 23527, X 1. Fig. 15a, dorsal view; fig. 15b, outer view; fig. 16, lateral view. Bautista beds, California. from Rancho La Brea in the collections of the University of California. It further differs in having a larger and deeper fossa, and in being proportionately broader with the mid-dorsal groove of the proximal trochlea surface more shallow. The specimens suggest the occurrence of a small undescribed species of Capromeryx, even more diminutive than the Rancho La Brea form, which represents one of the smallest of Pleistocene ungulates. ANTILOCAPRA?, one or more species Material—A basal portion of a horn core, no. 23453, and two sections of smaller horn cores, no. 23420 (figs. 17, 18a-18b), all Univ. Calif. Coll. Vert. Pal., general loe. Univ. Calif, 3247. An astragalus, associated with a navicular-cuboid, a cuneiform, and pieces of a caleaneum (figs. 13a—13c), nos. 24016, 23235, 23759, 23528, 23403, 24017, 23404, Univ. Calif. Coll. Vert. Pal., Univ. Calif. loc. 3243. Discussion.—The specimens shown in figures 17 and 18 are of the flat-horned antelopine type. They are believed to represent the basal a —— 1921] Frick: Faunas of Bautista Creek and San Timoteo Caron 301 and distal horn portions of some unrecognized member of the Antilo- capra or capromeryx groups furnished with horns of Old World tragocerine type. if ; 4 WF iy / dt {- y Hf) FGA 1) ( M/) i) th 18b Figs. 17 to 18b. Antilocapra?, sp. Portions of horn cores, X 1. Fig. 17, no. 23453; figs. 18a and 18), two sections, no. 23420. Bautista beds, California. The astragalus no. 23403 (fig. 13), which is unfortunately some- what broken, evidences strong cervid relationship, showing dorsally the broad and full cervid-like contour of the outer condyle of the trochlea, as ventrally the wide median grooving of the broad caleaneal surface. The specimen, however, in contradistinction to two shghtly larger cervid-like astragali (see above), resembles somewhat more the 302 Umversity of California Publications in Geology [ Vou. 12 Antilocapra type in the character of the median groove of the distal end, which is shallow and continuous with the slope of the adjacent condyle, and in the presence of but the single inner trochlea-knob on the dorsal surface. Furthermore, the posterior facets of the navicular- cuboid articulating with the cuneiform lie at a right angle instead of an acute angle as seen in Odocoileus. The caleaneum is lighter and apparently shorter, and the first and second phalanges narrower and considerably lighter than in O. hemionus. EQUUS BAUTISTENSIS, n. sp. Type.—Three associated premolars from the left side of an upper jaw, Univ. Calif. Coll. Vert. Pal. nos. 23239, 23238, 23245 (folder 2, fig. 1), Univ. Calif. loc. 3243. To this species is referred all of the Bautista equine material, including upper and lower cheek teeth, incisors, and limb elements, as enumerated and described below (figs. 19-25, folder 2, pl. 45). Referred Material. Upper cheek teeth: Three molars of the left side of the upper jaw, figured in series with the type premolars, Univ. Calif. Coll. Vert. Pal. nos. 28245, 23246, 23247, Univ. Calif. loc. 3243 (folder 2). A compiled right series of unassociated teeth from upper jaw, all from the same locality as the type (folder 2, fig. 2), Univ. Calif. Coll. Vert. Pal. no. 23236, Univ. Calif. loc. 3244. A partly associated series of worn teeth from upper right jaw (folder 2, fig. 3), Univ. Calif. Coll. Vert. Pal. no. 23244, Univ. Calif. loe. 3244. Lower cheek tecth: A fragment of mandible containing associated lower series (lacking Mj), (figs. 19, 23), Univ. Calif. Coll. Vert. Pal. no. 23196, Univ. Calif. loe. 3248. Section of a mandible with portions of all the series except P3 (figs. 21, 24), Univ. Calif. Coll. Vert. Pal. no. 23913, Univ. Calif. loc. 3240. Various lower cheek teeth (figs. 20a—20c, 22a—22c), Univ. Calif. Coll. Vert. Pal. nos. 23241, 3048 “ofo5e, 23250, 232414, 23249, Univ. Calif. loc. 32438. Incisors: A set of incisors in a fragment of the premaxillary (fig. 25), Univ. Calif. Coll. Vert. Pal. no. 23348, Univ. Calif. loc. 3243. Limb elements: A metacarpus (pl. 45, fig. 1), Univ. Calif. Coll. Vert. Pal. no. 23460, Univ Calif. loc. 3245. The proximal and distal portions of a second metacarpus associated with the first, second, and portion of a third phalanx, unciform, magnum, trapezium, and seaphoid (pl. 45, fig. 2), Univ. Calif. Coll. Vert. Pal. no. 23466, Univ. Calif. loc. 3242. An associated series of bones of the right hind limb from Univ. Calif. locality 3241, as follows: Proximal and distal portions of femur (pl. 45, fig. 6), no. 23489. Proximal half of tibia (pl. 45, fig. 7), no. 23472. An astragalus and caleaneum (pl. 45, figs. 3b-3c), no. 23463. Third metatarsal with first and second phalanges (pl. 45, fig. 3a), no. 23459, Univ. Calif. loc. 3241. Fig. 1 outer aspect Fig. 2) d, €, Cross seq Fig. 3 Coll. Vert. P | 3243, 23246, 23247; a, occlusal view, natural size; b, c, d, ect of no. 23236, X %; ¢, outer aspect.no. 23786, X 14; of P? and P2, nos. 23253 and 23258, X 1%. All Univ. Calif. é FOLDER 2 EXPLANATION OF IOLDER 2 Upper dentition of Lquus bautistensis, n.sp. Bautista beds, California. Fig. 1. Associated P2, P3, and P! of type specimen, Univ. Calif. Coll. Vert. Pal. nos, 23239, 23238, 23245, and referred molars nos. 23243, 23246, 23247; a, ocelusal view, natural size; b, e, d, outer aspect of the type premolars. X 14. Fig. 2. Compiled series of six unassociated teeth, referred to the type; series no. 23236; a, occlusal views, natural size; b, inner aspect of no. 23236, X %. c, outer aspect.no. 23786, X V4; d, ¢, eross sections at d and e, no. 23786, natural size. All Univ. Calif, Coll. Vert. Pal. Fig. 3. P Gaiee artly associated series of much worn teeth, referred to type, series no. 23244; a, occlusal view, natural size; b, lateral view of P? and P2, nos, 23253 and 23258, % 14. All Univ. Calif. toll. Vert, Pal. instal pa ole, PRT apie Hott diet) aviall snomthage sept to BT jn PEST heseinog Mo paghomretg sopgt 8 ‘yb oilt ot Nartsiar gies patatjoenenu aie TO geftse belitapa POF Ug ie vie [lA .oste levadag (OATES vom has b Says of forse feet nrowes dt oneG ida vation be Hie } i s Seale, ~ i a . fs @4 ve . , as 7 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 303 The limbs are also represented by material from various localities which con- forms with the foregoing: Portions of navicular and cuneiform bones (pl. 45, figs. 4,5), nos. 234714, 23765. Cuneiform, no. 23765. Portion of cuboid, no. 23766. Inner pulley of astragalus, no. 23769. Head and pulley of a metatarsus, nos. 23468 and 23471. Metapodial pulley and fragment of a second, nos. 23467 and 23468. Distal portion of a first phalanx, no. 23469. Second phalanx, no. 23465. All in Univ. Calif. Coll. Vert. Pal. Various localities. Characters —Equus bautistensis is characterized by: (1) The prominent bilobed form of the anteroposteriorly elongated protocone in the large sized premolar teeth and by the considerable anterior extension of the protocone throughout the series, the protocone averag- ing longer anteroposteriorly than that of the Rancho La Brea form of Equus occidentalis Leidy; (2) the relative amount and complexity of the infolding of the fossette margins, which is less than that seen in certain of the later equines and more than that occurring in E. occidentalis; (8) the comparative narrowness in transverse diameter of the referred lower teeth, and the relative flatness of the outer faces of the protoconid and hypoconid ; (4) the average sharpness of the gutter of the metaconid-metastylid column, and the considerable prominence of the valley between the protoconid and hypoconid; (5) the depth of the referred mandible viewed laterally, as compared with EH. caballus, and the relatively shght concavity of the inferior border of the mandible anterior to the angle of the jaw as compared to EF. occidentalis of Rancho La Brea. Description.—The upper dentition is of large size. The mesostyle and parastyle of the premolars are relatively broad, in the molar series the styles become progressively narrower. The protocone is large and elongated, the anterior projection varying to less in well worn teeth (see series no. 23244, folder 2, fig. 3). In the premolars it is deeply bilobed, being sharply concave in the inner border; in the posterior portion of the series the protocone progressively lengthens, and becomes markedly narrower and flatter. The postprotoconal valley is broad in the premolars, and narrows slightly through the series. The de- velopment of the fold at the anterior end of the postprotoconal valley varies somewhat throughout the series, being considerable in certain premolars and in some molars. The fossettes are long and have a narrow appearance, owing to the deep incision of the opposed anterior and posterior walls. The inner walls are considerably complicated by University of California Publications in Geology [ Vou. 12 304 “BIMLOFITVO ‘Spoq BASTynVE ‘GFSES ‘VIFSES ‘OGTES ‘sou ‘ngzZ “Sy ‘(MTA [V19}eT 10 ‘Sy 008 EI6kS jou “IN 04 *d ‘Ts ‘SYS SSSkS ‘SFSES ‘THsesg ‘Sou ‘YJ00} yooyo ToMOL. 903 04 ie ae ec mern te Teeeet se 961es ‘ou “WwW 03 ?q ‘6L “SLA “LT X ‘SMeTA TeSNTD00 ‘UOTZTZUEp IamorT “ds ‘u ‘siswazsiynng snnb a ) I ic <1 pats Sm \y Seay fia See I04B[ OF EZ ‘SH 908) 08S 0} GL ‘SOLT 1921] Prick: Faunas of Bautista Creek TTT iN v8 ‘\\ - | \ Nt and San Timoteo Canon 305 Fig. 23, Bautista beds, California. , no. 23196; fig. 24, mandible with P3 to Mj, no. 239138. 2 Figs. 23 and 24. Equus bautistensis, n.sp. Fragment of mandible and lower teeth, lateral view, X 4. P; to M 306 University of California Publications in Geology [ VoL. 12 accessory plications, especially those of little to moderately worn teeth. The incisors are large and still deeply cupped (fig. 25) ; the strongly concave outer edge of each incisor overlaps the convex inner edge of the adjoining tooth. The lower dentition (figs. 19-24) is of a long and rather narrow- crowned type. The fold of the metaconid-metastylid column is broad, deep, and symmetrically V-shaped, becoming more open and asym- metrical in worn specimens through the simultaneous elongation of Fig. 25. Equus bautistensis, n. sp. Premaxillary with incisor teeth, no. 23348, xX %. Bautista beds, California. the metaconid. The inward folding between the protoconid and hypoconid is sharp, and deepens from the premolars to Ms. In a worn series (fig. 19) the fold is shghtly broader and rounder. In the molars the fold only meets the mouth of the metaconid-metastylid column (versus its much greater depth and breadth in old specimens of E. caballus). The inner wall of the hypoconid of Pz is considerably crinkled, as in EF. caballus. The outer faces of the protoconid and hypoconid are markedly flattened, especially in the premolars, perhaps even more so than in EF. caballus. The anterior portion of the entoconid resembles that of E. caballus, and the inward extent of the parastyld is similar. The mandible is very broad (fig. 24), measuring 101.6 mm. in depth in the region of P#. The inferior border is not concave as in E. caballus, nor does it show the deep coneavity anterior to the angle of the jaw seen in E. occidentalis of Rancho La Brea. It resembles more closely the mandible of E. scotti.'* The premazillary is expanded in the region of the incisors, and appears to be of rather elongated proportions, pointing to a propor- tionately long-snouted form. 12 Gidley, J. W. Bull. Am. Mus. Nat. Hist., vol. 18, p. 114, fig. 3, 1900. 1921] Prick: Faunas of Bautista Creek and San Timoteo Canon 307 MEASUREMENTS OF UPPER CHEEK TEETH OF EQUUS BAUTISTENSIS anteroposterior diameter ..................--..---- transverse diameter : ae anteroposterior diameter of protocone .. anteroposterior diameter .......................... transverse diameter ..........-...0-2....20-1- anteroposterior diameter of protocone .. anteroposterior diameter —...........:...-...-... transverse diameter ~............2..-22---2:00-00-+-+ anteroposterior diameter of protocone .. anteroposterior diameter .............2...2.--+- transverse diameter ............2...22--.21-0-20--- anteroposterior diameter of protocone.. ‘anteroposterior diameter .....................-.- transverse diameter ...............--.----.:+-00--+-- anteroposterior diameter of protocone.. anteroposterior diameter .................--..--- transverse diameter ...............2-..2:---2:--+ anteroposterior diameter of protocone.. No. 23244, etc. 10.9 mm. ep w&w to 19 \o) Bo) ie) No. 23239, etc., type, premolars (40.4) mm. 28.4 9.6 34.4 31.5 (14.3) 30.2 29.5 13.4 No. 23236, etc. 28.2 mm. (9.9) MEASUREMENTS OF LOWER CHEEK TEETH AND MANDIBLE OF EQUUS BAUTISTENSIS, REFERRED SPECIMENS Ie P;, lee P;, P3, P3 1, 1p Px anteroposterior diameter —_.......-............... transverse diameter ~..........-22..-2------0----- anteroposterior diameter of metaconid- metastylid column. .............2..220.22.-2022---- anteroposterior diameter —...........-...--..-... transverse diameter ..............----:---::---0---0+- anteroposterior diameter of metaconid- metastylid column .................-2:::.-----+++ anteroposterior diameter __......................-- transverse diameter ..............::-::c-ccceceeeees anteroposterior diameter of metaconid- metastylid column ..............2..--0-::--0---++ M;, anteroposterior diameter ..................--.--- M;, transverse diameter ...........22..22.--:-:0-0--0++ M;, anteroposterior diameter of metaconid- metastylid column .............222..-2222.---2---+ Nos. 23249, 23241, 23250, 23248 33.6 mm, 14.6 No. 23196 mandible 36.2 mm. 14.2 No. 23913 mandible 308 University of California Publications in Geology [ Vou. 12 MEASUREMENTS OF LOWER CHEEK TEETH AND MANDIBLE OF EQUUS BAUTISTENSIS, REFERRED SPECIMENS— (Continued) No. 23196 No. 23913 mandible mandible Mz, anteroposterior diameter —.......-0..... 28.2 mm. 29.7 mm. Mz, transverse diameter —...0000000000.eeee ee 12.9 14.4 M3, anteroposterior diameter of metaconid- mn tals tayclor lc oll rat eee usecase ezeeeneeee cee 14 14.7 Mz, anteroposterior diameter .....................--. 34.4 Mz, transverse diameter ............-...--2--00.e--0-t- 13.7 M;, anteroposterior diameter of metaconid- metastylid colmmm --2.222..2 occ. -cereeeseona 13.1 Limb elements.—The unciform facet of the metacarpus (pl. 45, fig. 1) is largely developed. Specimen no. 23460 is fully as large as the metacarpus referred to Equus pacificus (Univ. Calif. Coll. Vert. Pal. 2410), and is considerably shorter than that of a new form from Idaho (Univ. Calif. Coll. Vert. Pal. 3836c). In comparison with the fore cannon bone an unassociated hind cannon bone, specimen no. 23459 (pl. 45, fig. 3a), is unusually light and long (measuring 285 mm. versus 242 mm. in the former), it is more slender and slightly shorter than that of E. pacificus. This more than proportionate lightness of the posterior element is indicated by further fragmentary remains. The cuboid facet of the metatarsus is large, but is not so square in shape as in the modern draught horse. The cuboid facet of the caleaneum is also less developed posteriorly than in the latter (pl. 45, fig. 3c). MEASUREMENTS OF Hinp LimB ELEMENTS OF EQUUS BAUTISTENSIS Metacarpal III, no. 23460, greatest length ......-W......-.-----c--ccecceeceececeeeeeceeeeees 242 mm. Metacarpal III, no. 23460, transverse width of distal troch’ea _.............. 54 Metatarsal TU no. 23459; preatest lenght 2222-2 eccccceec eee ceccee 2 -cetescevecseeee-e= 285 Metatarsal III, no. 23459, transverse width of distal trochlea —.............. 53 Phalanx I, no. 23459, greatest length -.......--....-------c---ceeeeccetecceneceeeeeeeeteeeeee 92 ithalama WT, mos 234595 oneatest Vemphhy sa cce..e. cote c.ecceseteecere sees eeeeete oeeerees 95 Phalanx il non23209)) onreabesth: ler cit Hiss: scsccesseet ees ssnes asses seensaan ee saeeeeeneee 57 Phalanx Ul | m0 m234.59 someabesuelenor bil meee ees aeesee ss eeeeesnsenencs es eenes eee eeeraeenes 59 Comparisons.—Compared with the figured dentition of Equus scotti Gidley that of Equus bautistensis may be of a slightly more primitive type, in that: (1) the upper cheek teeth are narrower transversely, the molars are slightly shorter anteroposteriorly, and their mesostyles 1921] Prick: Faunas of Bautista Creek and San Timoteo Caron 309 are slightly lighter; (2) the protocones are shorter anteroposteriorly, and considerably less extended both fore and aft; (3) the borders of the cement lakes are less plicated ; (4) in the lower teeth the metaconid- metastylid column has less anteroposterior extension, and its inner groove is deep angular instead of shallow and flattened; and (5) the outer faces of the protoconid are perhaps less flattened. Compared with Equus occidentalis Leidy, as seen in the Rancho La Brea type, the premolars may be slightly heavier, though the cheek teeth in general are of similar size. The new form generally differs as follows: (1) the protocones average longer in fore-and-after diameter, especially in the premolars, where their anterior production is most marked; in the molar portion of the series the anterior corner of the protocone is narrowed to pointed, instead of more oval in shape as in EL. occidentalis; the inferior border of the protocone tends to be more deeply indented in the premolars, the postprotoconal valley is broader, and the accessory fold more marked than in the Rancho La Brea specimen; (2) the fossettes are broader and longer, and their borders are plicated, in contrast to the simple margins of E. occi- dentalis; (3) the lower cheek teeth average slightly narrower, and the fold of the metaconid-metastylid column averages somewhat deeper; (4) the outer faces of the protoconid and hypoconid are flatter than the more rounded faces of EF. occidentalis. Compared with Pliohippus proversus Merriam the weight of evidence indicates the more advanced stage represented by Equus bautistensis: (1) P? of the type specimen is but slightly larger than that of the P. proversus type specimen, its parastyle and mesostyle are but slightly lighter, and the styles of the teeth of both forms referred to the first molars are equal; (2) the protocone of the P2 has the greater anterior projection in the Bautista tooth, but the protocone of the M+ is as long anteroposteriorly in the Pliohippus proversus type; (3) the borders of the cement lakes are more complex and somewhat narrower in the Bautista form, though one specimen of P. proversus (no. 22328) shows a very considerable incision of the anterior lake margin; (4) in the lower teeth P; of the H. bautistensis appears of about equal size with that of the portion of the single large tooth (no. 21332) referred to P. proversus; the groove of the meta- conid-metastylid column of the Bautista form is markedly deeper and 13 Merriam, John C. Relationship of Equus to Pliohippus suggested by Char- acters of a New Species from the Pliocene of California. Univ. Calif. Publ., Bull. Dept. Geol., vol. 9, pp. 525-534, 1916. 310 University of California Publications in Geology [ Vou. 12 sharper than in the P. proversus tooth, while the anteroposterior length of the column is about the same. Compared with Equus idahoensis Merriam* (type and referred specimens, consisting of a worn P2 and M? from the Payette and Snake rivers, Idaho), EZ. bautistensis grinders are fully as specialized. The upper teeth are of nearly equal size; the transverse thickness of the protocone of P* of EH. bautistensis with its deeply indented inferior border somewhat suggests the premolar of EF. idahoensis. Points of difference are: (1) the anterior projection of the protocone in P2 of HE. bautistensis (of series no. 23244) is more pronounced than in the E. idahoensis P2 of the same stage of wear; (2) the large complicated lakes show no similarity to the narrow, simple, bordered fossettes of the worn Idaho P2, but, on the other hand, somewhat resemble those of the less worn Idaho M+, which, in turn, are relatively narrower and more compheated than those of the Rancho La Brea form; and (3) the post-protoconal valleys average broader throughout in the E. bautistensis teeth. A wide range of characters is shown in Equus stenonis™ as fig- ured by Dr. C. J. Forsyth Major. The Bautista specimens, however, are: (1) considerably larger than any illustrated under E. stenonis; (2) their protocones, while somewhat resembling those shown in figure 1 of Dr. Major’s plate, are shorter and much less produced anteriorly than those in his other figures; and (3) their lake borders are less complex than those of the illustrated teeth (excepting in the case of a worn series, figure 2 of the same plate, where the lakes of E. stenons, as might be expected, are less plicated than in the moderately worn teeth of EF. bautistensis). Equus sivalensis*® as figured by Dr. Lydekker suggests a stage of development similar to that of FE. bautistensis in both the size of the teeth and the amount of folding of the fossette borders, as well as in the degree of anteroposterior elongation of the protocone. The length of the protocone shown in E. namadicus, on the contrary, would indicate a considerably more advanced stage. Summary.—The dentition referred to Equus bautistensis in the summation of its character may be said to be of an advanced early 14 Merriam, John C. New Mammalia from the Idaho Formation. Univ. Calif. Publ., Bull. Dept. Geol., vol. 10, pp. 523-530, 1918. 15 Major, ©. J. Forsyth. Beitrige zur Geschichte der fossilen Pferde inbe- sonders Italiens. Abh. schweiz. palae. Ges., vol. 4, pt. 1, 1877. 16 Lydekker, R. Palaeontologia Indica, ser. 10, vol. 2, pt. 3, pls. 14, 15, 1882; Record Geol. Surv. India, vol. 43, pt. 4, 1913. 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 311 Equus type. It may represent a later stage in equine development than does Equus occidentalis of Rancho La Brea. ? and the apex of the suture line between the palatine and maxillary occurs opposite the anterior edge of Dp* versus that of M2 as in P. gracilis. There is also an interesting suggestion of the maxillary fossa which is present in Pliauchenia gigas, Alticamelus,®? and Camelops, but absent in Auchenia and Camelus. The second molar has not come into use, Dp? and Dp4 still remain in place. M+ and the deciduous molars are furnished with well developed parastyles and mesostyles, both being much more prominent than in the referred lower teeth. A cingulum crosses the inner extent of the posterior lobe of the first molar near the summit. Dp? is quadrate and molariform. Fig. 89 to 90b. Procamelus?, indet. sp. Fig. 89, anterior portions of pre- maxillaries with canines and incisors, no. 23480; figs. 90a, 90b, incisors, no. 1053; x 1. Eden beds, California. Specimen no. 23434, from the same locality, represents a more mature stage, M1, M2 being in place. The teeth are slighly heavier, otherwise similar to those of the preceding specimen. MEASUREMENTS OF No. 23434 ME Taniteroposterion diameter ecco. ce cee sreeeeee eer 23.5 mm, MES UVTI SVCES Oe (VAMC TOT: cress eusssecesceeecss sete sesnseteees eeeeeeee ess 17 M2, anteroposterior diameter .............-------:-------ce-eeeceeceeeeeeeee 21 VAS CANS VeTSC: CHC Crs cree accross ese 19.5 Specimen no. 23430 (fig. 89). The sharp, pointed premolars are recurved and caniniform, and greatly exceed the small canines in size. Long diastemas le anterior and posterior to the canines, and are arched in the usual manner. The form apparently differs markedly from that described under Procamelus edensis raki, type specimen, 52 Wortman, Jacob L. The Extinct Camelidae of North America and Some Associated Forms. Bull. Am. Mus. Nat. Hist., vol. 10, fig. 20, p. 125, 1898. 53 Matthew, W. D., and Cook, Harold J. A Pliocene Fauna from Western Nebraska. Bull. Am. Mus. Nat. Hist., vol. 26, pp. 8361-414, 1909. Merriam, John C. The Skul! and Dentition of a Camel from the Pleistocene of Rancho La Brea. Univ. Calif. Publ., Bull. Dept. Geol., vol. 7, pp. 305-323, 1918. Scott, W. D. A History of Land Mammals of the Western Hemisphere, p. 398, 1913. 1921] Frick: Fawnas of Bautista Creek and San Timoteo Canon 375 both in the long diastema occurring between the first premolar and the canine, and in the very small size of the canine teeth. No material exists for comparison with the smaller mandibles described above under P. edensis edensis, or Procamelus, species A, to one of which species the specimen may belong. MEASUREMENTS Procamelus? edensis Indeterminate edensis, n. sp. no. 23430 no. 23428 Length of diastema posterior to Pj -.................- 17+ mm. 51 mm. Anteroposterior diameter P; at alveolus ~........... 8.3 9.4 Length of diastema anterior to Pj .........2..---.------ 15 2 Anteroposterior diameter of canine at alveolus — 6.5 9.3 P;, apparent height above alveolus .................... 13 Apparent height of canine above alveolus ........ ) PROCAMELUS? FORMS WITH STOUT LIMBS Material—aA long slender first phalanx and a referred metapodial trochlea, nos. 23392 and 23391 (fig. 78, also pl. 48, figs. 8a, c); the proximal portion of first phalanx, no. 23393 (pl. 48, fig. 8b); the proximal portions of several meta- podials, no. 24032 (fig. 93a), no. 23493; and seven astragli: no. 23383 (fig. 94D), no. 23382 (fig. 94a) with associated portion of tibia and tarsal joint; and nos. 22379, 23380, 709, 485, and 821. All specimens in Uniy. Cal. Coll. Vert. Pal. All from Univ. Calif. Eden localities. Discussion.—The long, slender phalanx (fig. 73) and other material of this section suggests the presence of a large Procamelus-like form or forms. The scale drawings of various limb elements (figs. 71-73, 91-94, pl. 48) indicate the great size difference between the material and that described above under Pliauchenia (?Megatylopus Matthew). The phalanx, no. 23391, is fully as long as those of the smaller of the two foregoing Pliauchenia specimens, described under P. mer- riamt, but is noticeably lighter, the shaft being greatly constricted in its middle region, where it measures but 18 mm., instead of 27 mm. as in species A. Another first phalanx, represented by the proximal portion, no. 23393 (pl. 48, fig. 8b) is somewhat smaller. It may represent the opposite limb or a size variation of the first. A number of trochleas of equal size, nos. 23486 and 24032 (fig. 92d), and the proximal portion of metapodial no. 23493 (fig. 93a) agree in general proportions with the foregoing phalanges and may represent the same or similar species. The representation of more than a single species in the material of this section is indicated in the variation in a fine series of camelid 376 University of California Publications in Geology [ Vor. 12, astragali. This is marked in the two that are nearest of height, nos. 23382 and 23383 (figs. 94a and 94D), the first differmg from the second in: (1) the transverse narrowness of the dorsal trochlea through thinness of the outer condyle and narrowness of the inner groove; and (2) the prominence of the outer condyle of the ventral troch- lea in respect to the inner condyle. PROCAMELUS(?) FORMS WITH SLENDER LIMBS Material—A small second phalanx, no. 23385 (pl. 48, fig. 3); the trochlea of two first phalanges, nos. 23386, 23773 (pl. 48, figs. 5a, 5b); the proximal por- tion of two metapodials, nos. 23480 and 23479 (figs. 93b, 93c) ; the distal end of a humerus, no. 24284 (fig. 92d); an ulna- radial section, no. 23482 (pl. 48, fig. 9); a seaphoid, no. 24035 (pl. 48, fig. 7a) ; and seaphoid no. 23399 (pl. 48, fig. 7b). Various localities, all specimens in Univ. Calif. Coll. Vert. Pal. Discussion.—The trochlea of two slender first phalanges, nos. 23386 and 23773 (pl. 48, figs. 5a-5b) are considerably heavier than that of phalanx no. 23387 (pl. 48, figs. 2a— 2b) of the following section. The two fragments are believed to rep- resent the moderate sized species further suggested by the other material of this section. Specimen no. 23386 is very similar and but slightly larger than one from the Coalinga Etchegoin (no. 21243) in the Univ. Calif. Coll. Vert. Pal. Fig. 91. Procamelus?, sp. Cannon bone, no. 23422, anterior and lateral views, X 14%. Eden beds, California. 1921] Frick: Faunas of Bautista Creek and San Timoteo Caton 377 A perfect specimen of a small second phalanx, no. 23385 (pl. 48, fig. 3), was found with no. 23387 of the following section. Like the referred fragments of first phalanges and metapodials it is of a con- siderably stouter form than the specimens of the following section. 92b Figs. 92a—92d, 93a-93c, 94a-94b. Pliauchenia and Procamelus. Limb elements, x \%. Figs. 92a, 92c—92d, distal ends of humerii: fig. 92a, Pliauchenia merriami, n. sp., no. 23483; fig. 92c, sp. A, no. 23484; fig. 92d, Procamelus, sp., no. 24284. Figs. 93a-93c, Procamelus, sp., proximal ends of metapodials: fig. 93a, no. 23493; fig. 93b, no. 23480; fig. 93c, no. 23479. Figs. 94a-94b, astragali: fig. 94a, Pro- camelus, sp., 00. 23382; fig. 94b, Procamelus?, sp., no. 23383, Fig. 92b, Pliauchenia, sp. A, no. 23484, Eden beds, California. 378 University of California Publications in Geology [ Vou. 12 PROCAMELUS FORMS WITH VERY SLENDER ELONGATED LIMBS Type.—An exceedingly long and slender metapodial, Univ. Calif. Coll. Vert. Pal. no. 23422 (fig. 91), loc. 3269. Referred material—The distal portion of a small metapodial, no. 23498 (pl. 48, fig. 1); and a fragment of the distal end of a first phalanx, no. 23387 (pl. 48, figs. 2a, b). Description.Specimen no. 23422 (fig. 91) suggests a tall, slender- shanked, gazelle-like form, being of very small cross-section and yet equalling in length that of large specimens of Procamelus robustus. As viewed from the front this cannon bone is remarkably long and slender; in lateral aspect the posterior outline is somewhat bowed 35 Figs. 95 and 96. Cervidae. Fragments of a lower tooth, no. 24036, and of an astragalus, no. 23779, KX 1. Eden beds, California. through thickening in the middle region; posteriorly a deep groove marks the junction of the two metapodials, which are firmly codssified except at the distal separation. The distal ends are but little expanded transversely ; they are more than proportionately developed laterally, the trochleas having a strong backward inflection. The keels of the plantar surface are very prominent. MEASUREMENTS OF METAPODIAL No. 23422 MM Galil era pth seo see eae ee oa ce a380 mm, Mengthvot distal separation 2ccescseceeces cceceee ere sereneer serene 65 Anteroposterior diameter of single trochlea ....................-.-- 32 Transverse diameter of single trochlea .............-..-.-------0--0----- 23 a, approximate. CERVIDAE CERVID, sp. Material—The portion of a small premolar, no. 24036 (fig. 95), and the inferior half of a medium sized astragalus, no. 23779 (fig. 96); both in Univ. Calif. Coll. Vert. Pal. 1921] Frick: Faunas of Bautista Creek and San Timotco Catton 379 Discussion.—The occurrence of the portion of a short crowned premolar is of great interest as indicating the presence of at least one brachyodont deer-like form among the tall-crowned antelope of this horizon. It may represent the dentition of the cervid species, whose presence is further suggested by the portion of an astragalus (fig. 96). 97a 97b 100 Figs. 97a-97c, 98a—98c-100. Antilocapra?, n.sp. Cheek teeth, X 1. Figs. 97a to 97c, Mz, no. 23408, outer, inner and occlusal views; figs. 98a to 98c, upper molar, no, 23406, outer, inner and occlusal views; fig. 99, portion of upper molar, no. 23780; fig. 100, M3, no. 28407, occlusal and inner views. Eden beds, California. ANTILOCAPRIDAE The portion of a forked horn or horn core and specimens of long, narrow-crowned, upper and lower molar teeth are here tentatively referred to the antilocaprine group on the evidence of a slight resemblance of the horn core, and of the marked similarity of the associated teeth to those of the living form. The material may repre- sent a single species or widely differing species. 380 University of California Publications in Geology [ Vou. 12 ANTILOCAPRAY, n. sp. Material.—A forked horn or horn core, no. 23421 (fig. 101); an upper molar, no. 23406 (figs. 98a-98c); and a last upper molar, no. 23407 (fig. 100); all from Univ. Calif. loc. 3269. A portion of an upper molar, no. 23780 (fig. 99), and of a lower molar, no. 23408 (figs. 97a—-97c), from Univ. Calif. .loc. 3266. All in Univ. Calif. Coll. Vert. Pal. Fig. 101. Antilocapra?, n.sp. Horn core, with outlines of cross sections, no. 23421, X 1. Eden beds, California. Description.—The horn specimen (no. 23421, fig. 101) may repre- sent either: (1) some unknown Pliocene form near Antilocapra, the specimen somewhat resembling the left horn core of a large prong horn, but being of greater size with the portion above the fork thick- ening instead of tapering (cross-section posterior to fork in no. 23421 27.5mm. and in a large antelope 21mm.); or (2) the beam section of an antler of some large cervid, which is strongly suggested on 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 381 comparison with elk-like forms though no such ecervid is yet known from so early an American horizon. The lower molar (no. 23408, figs. 97a-97c) is of long-crowned, antelopine form, resembling a tooth from Thousand Creek which has been tentatively referred to Sphenophalos Merriam.** Anteroposter- iorly it is longer than the Nevada tooth, and the corresponding teeth of the living antelope, but transversely is somewhat narrower. Other slight differences between the specimens and teeth of Antilocapra are the somewhat greater development of the styles, and the absence of the strong backward inflection of the inner tooth lobes. COMPARATIVE MEASUREMENTS OF TEETH No. 12604 referred to Sphenophalos No. 23408 Antilocapra* or Ilingoceros* M3, anteroposterior diameter of crown.... 16.4 mm. 14.4 mm. 14.5 mm. M3, transverse diameter of crown .............- 7.3 thet 7 * Teeth are but slightly worn and the measurements are taken at the middle of the crown. Though the anterior crescent of the third upper molar (no. 23407, fig. 100) has disappeared, and only a trace of the posterior crescent remains, the tooth is still noticeably long-crowned. The specimen is of the same relative proportions as no. 23408 (figs. 97a—-97c) and is believed to represent the same species. The inner lobes, in a more modified degree than in specimen 23408, are less angular and less forwardly directed than those of the otherwise very similar last superior molars of Antilocapra. COMPARATIVE MEASUREMENTS Mature male antelope Old Univ. Calif. specimen Mus. Vert. Univ. Calif. Zool. Coll. Vert. No. 23407 no. 8298 Pal. no. 19231 M3, anteroposterior diameter .............. 20.38 mm, 20mm. 19.5 mm. M3, transverse diameter —..............-........- 10 10 10 The portion of an upper molar, no. 23406 (figs. 98a—98c), and the shell of a second, no. 23780 (fig. 99), from Univ. Calif. loc. 3266, are long-crowned and of the general relative proportions of the former teeth and may represent the same species. Tooth no. 23406 is con- siderably worn and in size lies intermediate between two specimens from Thousand Creek. The styles project less than in the present day pronghorn. 54 Merriam, John C. Tertiary Mammal Beds of Virgin Valley and Thousand Creek of Northwestern Nevada. Univ. Calif. Publ., Bull. Dept. Geol., vol. 6, pp. 285-292, 1911. 382 Unversity of California Publications in Geology [ Vou. 12 COMPARATIVE MEASUREMENTS Antilocapra Univ. Calif. Upper Molar Coll. Vert. No. 23406 Pal. no. 8929 Anteroposterior diameter 15 mm, 15.5 mm. MANS ViELS@ GaN CU Cy ce recseesceseaeceeeee nes eenee eran 10 11.5 MERYCODUSY, Sp., or ILINGICEROS?, sp. Material.—Portions of a small carpus, metacarpus, and radius, Univ. Calif. Coll. Vert. Pal. no. 23482 (figs. 102a, 102b), Univ. Calif. loc. 3274. Discussion.—The carpal bones, and portions of metacarpus and radius, Univ. Calif. Coll. Vert. Pal. no. 23432 (figs. 102a, 102b) belong “ iy CU ee 102a % 102b Figs. 102a, 102b. Antilocapra?, n.sp. Incomplete carpus, no. 23432, XK 1. Fig. 102a, lateral view; fig. 102b, front view. Eden beds, California. to a smaller animal than the cervid-like tooth and astragalus listed above, and may represent a small species near Merycodus, or some antelope form such as Ilingoceros. EQUIDAE The collection consists of some two hundred non-associated and associated cheek teeth showing a considerable range of pattern and size, a large number of incisors, and certain limb elements. Individual variation and the stage of wear where there is scarcity of material often erroneously suggests multiplicity of form. Many cross-sections have been made in the case of the present teeth, and they have assisted in determining to what extent the characters noted in these specimens have been due to age. As none of the upper teeth occurred definitely associated with the lower teeth, and as teeth and 1921] Prick: Faunas of Bautista Creek and San Timoteo Canon 383 limb material were never closely associated, each of the three is con- sidered in a separate division. The writer has divided the upper teeth into two main groups, and tentatively the lower teeth into two corre- sponding groups, as follows: Upper CHEEK TEETH (1) Group of Pliohippus osborm.—A group (see descriptions below) in which the specimens exhibit strong Equus character, in the marked anterior projection of the protocone and the grooving of its inner margin, a degree of this anterior projection being retained in even much worn teeth. Two forms are recognized: (1) Pliohippus osbormi, n. sp.; and (2) P. osborni, subform A. The distinction between the two, however, which is mainly one of size, may be sexual. This group apparently represents an important and unrecognized transitional stage in equine development. Somewhat similar but more Equus-like teeth have been noted in the overlying beds (see figs. 38a— 38b, 39a—-39b, Pliohippus francescana minor, n. subsp.). (2) Group of Pliohippus edensis—A more typical Pliohippus group (see description, p. 388), in which in moderately worn teeth the protocone is narrow and backwardly directed and in which in aged teeth the protocone tends to thicken and to become more oval in cross-section. Three forms are recognized: (1) Pliohippus edensis, n.sp.; (2) P. edensis, subform A, suggesting P. spectans Cope of the Rattlesnake; and (3) P. edensis, subform’B. At the end of the group are listed certain indeterminate teeth, including those of the milk series. PLIOHIPPUS OSBORNI, n. sp. Type.—A large moderately worn upper cheek tooth from the right side, Univ- Calif. Coll. Vert. Pal. no. 23787 (figs. 103a—-103f, 129), Univ. Calif. loe. 3269. Referred specimen.—A large third upper molar, Univ. Calif. Coll. Vert. Pal. no. 23338 (figs. 104a, 104b), same locality. Characters.—The strong tendency towards the Equus rather than the Pliohippus type, as shown by the elongated anteroposterior and thick transverse diameters of the protocone, together with the broad production of the anterior corner of the protocone and the indentation of its inner margin. A corresponding equine flatness of the outer walls of the protoconid and hypoconid is noticed in certain of the lower teeth occurring in the same beds (see figs. 127 and 128). 384 University of California Publications in Geology [ Vou. 12 Description.—The angle of the external faces of the type specimen, the transverse breadth of the anterior edge, the anteroposterior length, and heaviness of the parastyle suggests P#. The type and referred specimen are of large size in comparison with the teeth of the subform and with the more typical Pliohippus teeth from the same beds, compare third molars referred to type (figs. 104a-104b) and to 103f 105b Figs. 103a to 105b. Pliohippus osborni, nu. sp. Premolar and molar teeth. Figs. 103a—103f, type, no. 23787: fig. 103a—103b, outer and front views, X 14; fig. 103c, occlusal view, X 1; figs. 103d-103/, sections through m, n and o respectively. Figs. 104a, 104b, referred M3, no. 23338: fig. 104a, outer view, X 14; fig. 104b, occlusal view, X 1. Figs. 105a, 105b, Pliohippus osborni, subform A, small M3, no. 23350: fig. 105a, outer view, X 1; fig. 105b, occlusal view, X 1. Eden beds, California. subform A (figs. 105a—-105b). The crowns are long and well curved. The parastyle is relatively strong, the mesostyle well developed. The protocone is large (the anteroposterior diameter being twice the trans- verse), the cusp projects considerably anteriorly, and is slightly indented in the inferior margin; the main postprotoconal valley is relatively narrow, and is extended at the head, where a slight sub- sidiary fold is developed. Cross-sections of the type specimen (figs. 1921] Frick: Faunas of Bautista Creek and San Timoteo Cafion 385 103d, e, f) illustrate moderately and excessively worn stages, showing the following age characters: (1) the retention to a considerable degree of the protocone characters of the moderately worn state; and (2) the usual transverse narrowness and accompanying constriction and attenuation of the fossettes and styles; (3) the narrowing of the post- protoconal valley and loss of accessory fold. 110 Figs. 106 to 110. Pliohippus osborni, subform A. Premolar and molar teeth. Fig. 106, premolar, no. 24037, occlusal view, X 1, inner view, X 4%; fig. 107, referred molar, no. 23334, occlusal view, X 1; outer view, X 14; fig. 108, referred molar, no. 23336, occlusal view, X 1; fig. 109, referred molar, no, 23332, occlusal view, X 1; fig. 110, referred molar, no. 23346, occlusal view, X 1. Eden beds, California. PLIOHIPPUS OSBORNI, subform A Type specimen.—A slightly worn tooth from the left side of the upper jaw, Univ. Calif. Coll. Vert. Pal. no. 24037 (fig. 106), Univ. Calif. loc. 3269. Referred material.—Premolar, no. 23334 (fig. 107), and nos, 23336, 23332, and 23346 (figs. 108, 109, 110); and M3, no. 23350 (figs. 105a-105b). All in Univ. Calif. Coll. Vert. Pal.; all from same locality as the type. 386 University of California Publications in Geology [Von 12 Characters.—Relative small size, well illustrated by a comparison of the referred third molar (figs. 105a-105b), with that of the referred third molar of P. osborni (figs. 104a—-104b). Description.—All small teeth, such as no. 24037 (fig. 106), which resemble the type P. osborni in the unusual form of the protocone, are placed in this subdivision. Tooth no. 24037 (fig. 106) is believed to represent P? on account of transverse proportions and the extension of the anterior horn of the postfossette with respect to the posterior horn of the anterior fossette. It is more markedly narrow in its pro- portions than the type specimen of P. osborni (no. 23787, figs. 103a— 103c). This noticeable transverse narrowness is characteristic of the referred smaller teeth. It is noted especially in no. 23334 (fig. 107). but is seen in cross-section to be greatly influenced by the state of wear, the tooth becoming thicker transversely and narrower antero- posteriorly in the worn state. The lakes in moderately worn specimens are small proportionally, with single folds in their opposite margins ; in more worn teeth they become increasingly broader; in well worn teeth they narrow and tend to disappear. COMPARATIVE MEASUREMENTS a _ _P. edensis ; Pliohippus ie P. osborni, (spectans- P. edensis osborni francescana A sp. like) edensis no. 23787 no. 23275 no. 24037 no. 24039 no. 23331 : type referred type type type Greatest anteroposterior diam- Cb Cra See een ae 27mm. 303mm. 26 mm, 26.6mm. 23.7 mm. Greatest transverse diameter .. 27 28.7 25.5 27.2 23.2 Greatest anteroposterior length of metaconid-metastylid ...... 10 8.6 8.2 7.4 8.2 Conclusion.—The type specimen of Pliohippus osborni strangely approximates a P2 referred to the smaller of the two horses occurring in the overlying San Timoteo beds (P. francescana minor, no. 23275, figs. 88a—88b, 39a—39b ; folder 3, fig. 4). It differs widely and markedly from the average Pliohippus types seen in the upper teeth of its own horizon, which have more of the typical Pliohippus primitiveness. The smaller teeth of subform A may represent no more than a sexual variation. A large lower tooth, no. 23222 (fig. 127) is seen to be of advanced form when compared with the average lower teeth from the Eden formation, and in character and size might well belong with the advanced P. osborni type represented by the upper tooth. 1921] Frick: Faunas of Bautista Creek and San Timoteo Caron 387 112 118b Figs. 111-118b. Pliohippus edensis, n.sp. Premolar and molar teeth. Fig. 111, type specimen, molar no. 23331, occlusal view, X 1, outer view, X 14; fig. 112, referred molar, no. 23233, ogglusal view, 1; fig. 113, referred premolar, no. 23329, occlusal view, X 1, outer view, X 1%; fig. 114, referred premolar, no. 23284, occlusal view, X 1, inner view, X 4%; fig. 115, referred premolar, no. 23333, occlusal view, X 1; fig. 116, a last molar, no. 23337, occlusal view, X 1, outer view, X 4; fig. 117, referred molar, no. 23207, inner view, X 14, with cross sec- tions through x and y, X 1; figs. 118a, 118b, jaw fragment with M* and M?, no. 23349, fig. 118a, inner view, X 1%; fig. 118b, occlusal view, XK 1. Eden beds, California. 388 University of California Publications in Geology [ Vou. 12 PLIOHIPPUS EDENSIS, n. p. Type specimen.—A small, moderately worn upper cheek tooth from the right side, Univ. Calif. Coll. Vert. Pal. no. 23331 (fig. 111), Univ. Calif. loe. 3269. © Referred specimens.—Premolars, nos. 23329, 23284, 23333 (figs. 118-115); molars, nos. 23233 and 23207 (figs. 112, 117) , M$, no. 23337 (fig. 116); and frag- ment of jaw containing P* and M}, no. 23349 (fig. 118). All specimens in Univ. Calif. Coll. Vert. Pal.; all from Univ. Calif. loc. 3269. Characters—The moderate size, the long, narrow, curved crowns, the thin, elliptically-shaped, and backwardly directed protocone which entirely lacks anterior projection. DescriptionA comparison of the type specimen (no. 23331, fig. 111) and the directly referred specimens suggests that the type repre- sents P4, the other teeth respectively three Ps, an M1(?), an M2(?), and an M%. The type specimen is moderately worn (compare fig. 118 and tooth sections, fig. 117). The styles are hight. The narrow, elliptically-shaped protocone is bent characteristically backward, and is quite lacking in anterior extension. In moderately worn teeth the protocone tends to narrow in transverse diameter toward the rear of the series. In worn teeth, such as are illustrated by the sections of a molar (no. 23207, fig. 117) and P4 and M?# (fig. 118), the protocone is seen to retain much of its original form though tending to shorten slightly anteroposteriorly and broaden transversely. The postproto- conal valley in the type specimen and in the referred molars is narrow and without the accessory fold which occurs in the wider valleys of the three upper third premolars. The lakes as compared with those of the following type are of very moderate size, being smallest in the molars; their margins are somewhat indented, especially in the more slightly worn upper third premolars. MEASUREMENTS OF TEETH OF PLIOHIPPUS EDENSIS, N. SP. No. 23331 No. 23329 No. 23333 Anteroposterior diameter of crown 23.7 mm, 25.8 mm. 25.9 mm. Transverse diameter of crown .......... 23.2 24 21 Length of protocone of crown .......... 2 ) 8 PLIOHIPPUS EDENSIS, subform A, PLIOHIPPUS SPECTANS-LIKE Type.—A large and slightly worn tooth from the right side, Univ. Calif. Coll. Vert. Pal. 24039 (figs. 119a, 119b, 119¢c). Referred matevial—A worn molar, Univ. Calif. Coll. Vert. Pal. no. 23328 (fig. 120); both teeth from Univ. Calif. loc. 3269. Additional material—Second premolar, Univ. Calif. Coll. Vert. Pal. no. 23234 (fig. 122b), Univ. Calif. loe. 3269. 1921] Prick: Fawnas of Bautista Creek and San Timoteo Canon 389 Characters——The larger size, the relatively anteroposterior short- ness of the protocone and great transverse depth of the lakes in both the moderately and much worn stages; the general Pliohippus spectans- hke appearance. Description.—Specimen no. 24039 (figs. 119a—-119c) is but moder- ately worn and is believed to represent P4. It is of markedly greater 119c Figs. 119 to 120. Pliohippus edensis, subform A, P. spectans-like. Figs. 119a— 119¢, premolar, no. 24039, inner view, X 14; occlusal view and cross section, X 1. Fig. 120, referred molar, no. 23328, inner view, X 14; occlusal view, X 1. Eden beds, California. size than the premolars of the preceding section, and the protocone is proportionately smaller. The lakes are large and deep. The con- volutions in their inner borders disappear in age as seen in eross- section. The cross-section suggests the referred worn molar (no. 23328, fig. 120). This last tooth, though differing in actual measurements, being of smaller size and more worn, strongly resembles the P. spectans type described by Cope from the Rattlesnake. COMPARATIVE MEASUREMENTS Pliohippus P. edensis edensis, subform A, P. spectans subform A, referred type Univ. Calif. Univ. Calif. specimen* Coll. Vert. Coll. Vert. Am. Mus. Pal. 24039 Pal. 23328 Cope Coll. 8183 type Anteroposterior diameter ........ 26.8 mm. 24 mm. 27 mm. Transverse diameter .................- 26.2 25 25.2 Length of protocone .................- if 7.5 7.5 * Measurements taken from cast of type specimen. University of California Publications in Geology [ Vou. 12 390 “BIULOZTTRD ‘sped uepy ‘LT &X ‘mora pesnpooo ‘qezt ‘sy ‘Hh X ‘Mota rJajno ‘pggL “By {L3gEs “OU GIL PUB FIN Pottozor ‘gq wlozqns ‘sisuapa. “J ‘QGZL ‘DGZI “S8LT “LT X ‘TSEgs ‘ou ‘refourard B JO SUOT}OAS SsOLd OM} “FZT SLT “L X ‘Kata Tesnpoo0 ‘G1 ZEs ‘ou ‘004 ‘q WLOF -qns ‘siswapa ‘d ‘G20 “Stl “A X ‘Mars Joyo ‘Eezeg ‘ou ‘OZZl “SY fT X ‘META [esno00 ‘utoF [Tews ‘segeg 0U ‘QZZI “SU ‘L X ‘morta Tesn[o00 ‘iejourerd puodses podioyer ‘gq waosqns ‘cgzpy ‘ou “MZZl ‘8H tzq “ds ‘u ‘sysuapa “q ‘GBI OF PGET ‘ssiuq "YX ‘mata Ioqno ‘QIZL “SE fT X ‘Mora [esnpI00 “PTET ‘Sy :E61ES ‘OU ‘Sottas 400} yooyo soddn ‘aourtseds addy ‘gq wadoFqns ‘sisuapa “g ‘QIZl ‘PIZE ‘S8tq “worytjuep reddgQ ‘dsqns puv “ds u ‘sysuapa snddiyond “@got-Psel ‘SZI-EZL ‘OSST-PSST “AI SI-PISL SSL &ecl . Eel qGcl 1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 391 PLIOHIPPUS EDENSIS, subform B Type.—A complete series from the right side of the upper jaw, Univ. Calif. Coll. Vert. Pal. no. 23193 (figs. 12la-121b), Univ. Calif. loc. 3269. Referred material.—Second premolar, no, 24285 (fig. 122a); molar, no. 23219 (fig. 123); cross section of no. 23351 (fig. 124); M1, M2, no. 23327 (figs. 125a— 125d), Univ. Calif. loc. 3301; all others, Univ. Calif. loc. 3269. All in Univ. Calif. Coll. Vert. Pal. Characters.—The large size of the much worn teeth and the transverse thickness and inflection of the inner margins of the proto- cones, as compared with Pliohippus edensis, typical form, and with . P. edensis, subform A. Description—The teeth are very much worn. They are of large size, the protocones are more than relatively large, and their inner borders have a more angular inflection than those of other Pliohippus edensis teeth. The considerable size of the teeth is illustrated by comparison of the P? of type series and of referred specimen no. 24285 (fig. 122a) with the small P. edensis-like P?, no. 23234 (figs. 122b, ¢). The inflection of the inner border of the protocone is illustrated by comparison of the P4 of type series and specimen 23219 (fig. 123) with the P. edensis type tooth (fig. IL Certain somewhat similar teeth from the Eden representative of equally worn stages have protocones tenting more to the P. edensis type (see cross-sections no. 23351, and molars no. 23327, figs. 124, 125a-125b). These are only very tenta- tively placed in this section. The series of the B subtype is believed to represent a variation of the general Pliohippus edensis form. Cross-sections (figs. 107, 103e, 108) show the protocones of specimens of P. osborni of a fully equal stage of wear still retaining a certain amount of the typical anterior projection. PuioHippus Upper Mitk TEETH Material.—A small section of an upper tooth, Univ. Calif. Coll. Vert. Pal. no. 23220 (fig. 126b), Univ. Calif. loc. 3269. Two upper milk teeth, Univ. Calif. Coll. Vert. Pal. nos. 23202, and 23330 (figs. 126a, c). Description.—The tooth no. 23220 is of very peculiar pattern, but so fragmentary that the position of the section is undeterminable; it may represent a milk tooth. The protocone is remarkably oval in cross-section and, like the hypocone, is directed inward; the post- protoconid valley is greatly extended; the lakes are long and narrow. The tooth has some of the characters of the milk dentition; in its 392 University of Califorma Publications in Geology [ Vor. 12 square form, however, it differs from the usual milk tooth. It suggests in some ways Pliohippus fairbanksi, a form otherwise entirely un- represented in the collection. Bo S j ( 126b 126a Figs. 126a to 126c. Pliohippus upper milk teeth. Fig. 126a, no. 23202, inner view, X 14; occlusal view, X 1. Fig. 126b, no. 23220, occlusal view, X 1; fig. 126c, no. 23330, occlusal view, X 1. Eden beds, California. The teeth nos. 23202 and 23330 (figs. 126a, 126c) have some of the characters seen in the advanced Pliohippus, but their very narrow and short crowns indicate that they are milk teeth. LOWER CHEEK TEETH (1) A group (see description below) in which the specimens exhibit advanced Equus character, in the anteroposterior elongation of the metaconid-metastylid column, and in the flattening of the exterior faces of the protoconid and hypoconid. The section appar- ently embraces teeth of at least two subforms; these may correspond with the upper teeth described under Pliohippus osborni and P. osborni, subform A. (2) To a second group (see figs. 132-157c) has been assigned the balance of the lower teeth, which though separable into several forms are all of general average Pliohippus character, and are believed referrable to forms lying close to the new species Pliohippus edensis and subforms described under Upper Teeth. The subdivisions of this group are: (1) Medium sized lower teeth, near (?)Pliohippus edensis, n.sp.; (2) large lower cheek teeth near(?) subform B of the same; (3) teeth of narrow transverse diameter; (4) lower cheek teeth of remarkably small size and of uncertain relationship, and (5) speci- mens representative of the milk dentition. 1921] Frick: Faunas of Bautista Creek and San Timoteo Caron 393 Lower CHEEK TEETH TENTATIVELY REFERRED TO PLIOHIPPUS OSBORNI, N. SP. Material—An abnormally large tooth from the right side of the jaw, no. 23222 (fig. 127); and very tentatively placed with the same, a large molar, no. 23197 (fig. 128). Both specimens in Univ. Calif. Coll. Vert. Pal., Univ. Calif. loe. 3269. Description—tThe large lower tooth (no. 23222, fig. 127) is very Equus-like, especially in the flatness of the inner walls of the proto- Figs. 127 to 129. ?Pliohippus osborni, n.sp. Premolar teeth, outer and occlusal views, X 1. Fig. 127, no. 23222; fig. 128, no. 23197; fig. 129, Pliohippus osborni, n. p., upper premolar of type specimen, no. 23787, inner view, X 1. Eden beds, California. conid and hypoconid. The relative anteroposterior length of the crown, the transverse narrowness of the anterior end, and the depth of the fold between the protoconid and hypoconid point to the specimen representing the last premolar. The groove, or gutter, of the metaconid-metastylid column, unlike Equus, is sharp and deep; the wings of the metaconid and metastylid are broadly expanded and unsymmetrical, that of the metaconid being especially enlarged and produced forward and inward. The exterior faces of the protoconid 394 University of California Publications in Geology [ Vou. 12 and especially of the hypoconid are, as above noted, unusually fiat for Pliohippus. The fold between the protoconid and hypoconid extends in the form of a fine line within the mouth of the metaconid- metastylid, suggesting such a development and extension in the molars as is alone seen in the lower molars of the following section and in those of Pliohippus francescana of the overlying beds. The entoconid is very large and full. The specimen is very tentatively referred to the large upper tooth described as Pliohippus osborni no. 23787 (figs. 129, 103a-103/). Second specimen (no, 23197, fig. 128).—This tooth is long-crowned, of large size, and of exceptional proportions, the triturating surface being long anteroposteriorly and very narrow transversely. The wings of the metaconid-metastylid column are widely extended, the gutter is deep, and the exterior faces of the hypoconid are relatively flat, both protoconid and hypoconid being very narrow transversely. The specimen is evidently a molar. In character it is very like the larger specimen (no. 23222, fig. 127), excepting for its narrowness, though fully as great a reduction in the transverse breadth of the molars over the premolars at times is known to occur. The two teeth may represent the same species. MEASUREMENTS OF PLIOHIPPUS OSBORNI Referred Premolar molar no. 23222 no. 23197 Anteroposterior diameter of crown ............ 28.3 mm. 27.7 mm, Transverse diameter of crown ...........-..--.--.-- 14.3 10.6 Anteroposterior length of metaconid- Styli (Col tin seetecc scence dees oeeeet cee senneesanneees 16.6 14 LOWER TEETH, TENTATIVELY REFERRED TO PLIOHIPPUS OSBORNIT, subform A Material—A section of the mandible from the right side containing P;, Mj, Ms, and Mz, Univ. Calif. Coll. Vert. Pal. no. 23510 (fig. 181), Univ. Calif. loe. 3269. An M; with attached portion of Pz and an associated portion of P3, Univ. Calif. Coll. Vert. Pal. no. 23286 (fig. 180); the fragment of a mandible with P3 and P3, no. 24040. Both from the same locality as the type. Characters.—Proportionately great anteroposterior extension of the metaconid-metastylid column and openness of the gutter; the presence of a small accessory fold at the anterior inner corner of the protoconid in M;; the large size of M; as compared to P;; the deep, evenly concave, versus angularly convex, outer margin of the 1921] Prick: Faunas of Bautista Creek and San Timoteo Canon 395 protoconid, and the resulting unusual, rounded contour of the sides of the valley that divides the parastylid and metastylid; the consider- able production of the fold between the protoconid and hypoconid within the mouth of the metaconid-metastylid column of Pz, and the sudden and marked increase in the size and production of this fold in M;. Figs. 130,131. ?Pliohippus osborni, subform A. Lower cheek teeth. Fig. 130, two premolars and one molar associated, no. 23286, referred specimen, occlusal view, X 1. Fig. 131, Pz to Mg, no. 23510, type, occlusal view, X 1; outer view, xX %. Eden beds, California. MEASUREMENTS OF P. OSBORNI, SUBFORM A No. 23510 No. 23286 1B M; M3 M; Anteroposterior diameter of crown 27.3mm. 28.5mm, 25.2 mm. Transverse diameter of crown .......... 12.6mm, 12.7 elatealt 13.3 Anteroposterior length of pillar........ 13.6 15.1 13.5 15 Discussion.—Except for the suggested sharpness of the gutter of the metaconid-metastylid pillar, the teeth in the flatness of their inner faces and the great anteroposterior extension of the metaconid- metastylid would indicate the presence of an Hipparion form. This elongation of the metaconid-metastylid column of the new teeth is shown in comparison to that occurring in hipparions from the Rattle- snake and Ricardo Pliocene, as well as in Merychippus and Pliohippus in the following table.°° 55 Hipparion and Merychippus data through the kindness of Professor John C. Merriam. 396 University of California Publications in Geology [ Vou. 12 COMPARATIVE LENGTH OF METACONID-METASTYLID COLUMN IN PLIOHIPPUS, HIPPARION AND MERYCHPPUS Ratio of length of crown Ratio of breadth of crown to anteroposterior diameter to anteroposterior diameter of metaconid-metastylid of metaconid-metastylid pillar pillar INO PRIS IN ee .56 mm, 1.19 mm. INO.) 23 50% sis eee 50 1.21 INOS 238286) Mpc ee .60 1.12 H. leptode from Rattlesnake : 1 eget eens eeeesnee eee .60 1.22 H. mohavense no. 19788, P3; 62 1.23 H. mohavense, type, no. 21348, 2a eRe SNE 5, mr ee .60 1.10 Merychippus, average, P; .... 36-47 -77-.93 Pliohippus, average, P3 ........ 50 90 Remarks.—The type specimen represents a somewhat immature individual, M; being but slightly worn, and not having come into function. M; of the referred specimen is slightly heavier than that of the type, is in better condition, and illustrates the characteristic points to better advantage. In this specimen (fig. 130) there is a suggestion of a fold on the anterior border of the hypoconid of P; as seen in a Rattlesnake specimen (Univ. Calif. Coll. Vert. Pal. no. 544). The parastylid is moderately well produced. The entoconid is remarkably full and round. The groove of the elongated metaconid- metastylid column is deeper in Pz and much less flat than in Mj. These specimens are but very tentatively referred to P. osborni, sub- form A. MEDIUM SIZED LOWER TEETH, NEAR (?)PLIOHIPPUS EDENSIS, n. p. Material.—A left ramus containing P; to P3, no. 23195 (figs. 132b, 140), Univ. Calif. loc. 3269; and associated series representing P; to Mj, no. 23194 (figs. 133, 141c), Univ. Calif. loe. 3267; premolars, nos. 23231 and 23784 (figs. 135a—-135b) ; P;, nos. 23214 and 23209 (fig. 134a-134b); molars, nos. 23215 (figs. 136a, 141a), 23201, 23211 (figs. 186b-136c) ; molars, nos. 23352 (figs. 137a, 141b), 23226, 24283 (figs. 137b-137c) ; Mg, nos. 23230, 23287 (figs. 138a—138b); two very worn molars in jaw fragment, no. 23289 (fig. 189). All specimens in Univ. Calif. Coll. Vert. Pal. Characters.—The medium sized and generalized Pliohippus form; exterior faces of protoconid and hypoconid convex; groove between metaconid and metastylid column shallow and open; the moderate anteroposterior length of wings of metaconid-metastylid column, which is greater in premolars than in molars. 397 non Faunas of Bautista Creek and San Timoteo Can ° 1921] Frick 134b 139 Figs 132 to 139. ?Pliohippus edensis, n. sp. Lower cheek teeth, occlusal view, X 1. Fig. 132, P; to P3, no. 23195, and fig. 132b, cross section of P;. Fig. 133, three premolars and an associated molar, no. 23194. Two P3s: figs. 134a, no. 23214; fig. 134b, no. 23209 (reversed). Fig. 135a, 135b, premolars: fig. 135a, no. 23231; fig. 135b, no. 23784 (reversed). Figs. 136a to 136c, molars: fig. 136a, no. 23215; fig. 136b, no. 23201; fig. 136c, no. 23211 (reversed). Figs. 137a to 137c, molars: fig. 137a, no. 23352 (reversed, see fig. 141b for lateral view); fig. 137b, no. 23226; fig. 137c, no, 24283, Figs. 138a, 138b, Mj: fig. 138a, no. 23230; fig. 138b, no. 23287. Fig. 139, M; and Mz, no. 23289. Eden beds, California. 398 University of California Publications in Geology [Vou. 12 Discussion.—The section of a mandible, no. 23195 (figs. 132, 140), containing three premolars, and a second specimen representing M;, no. 23215 (figs. 136a, 141), are but shghtly worn, and illustrate the tall, downwardly tapering crowns of the unworn stage. The M; is in about the same stage of wear as that represented in the cross-section of Pz of the jaw specimen. The teeth of an associated series, no. 23194 (fig. 133), are somewhat more worn, but generally similar to those of the former specimen, no. 23195. The small molar tooth of no. 23194 is of considerable interest in showing the reduction in size of the posterior portion of the series in this type. The small jaw fragment containing M; and Ms; (fig. 189) is important in showing the relatively small size of M; of the worn teeth. er ce x ce 3 re if 140 Figs. 140 to 141¢c. ?Pliohippus edensis, n.sp. Lower cheek teeth of medium size, lateral view, X %. Fig. 140, three premolar teeth, no. 23195 (for occlusal view see fig. 182). Fig. 14la, molar, no. 23215 (for occlusal view see fig. 136a) ; fig. 141b, no. 23352 (for occlusal view see fig. 137a); fig. 141c, P3, no. 23194 (see fig. 183 for occlusal view of series). Eden beds, California. MEASUREMENTS No. 23195 No. 23352 No. 23226 IP 12 Molar Molar Anteroposterior length of crown 25.5mm. 25 mm. 25 mm. 25.2 mm. Transverse diameter of crown...... 12.5 14.5 13.2 13.2 Anteroposterior length of meta- conid-metastylid column .......... 12.9 12.6 12 12.3 Large LowER CHEEK TEETH, NEAR (?) PLIOHIPPUS EDENSIS SUBFORM B Material.—A second premolar, no. 23326 (fig. 144) ; premolars, nos. 23285, 93295 (figs. 146a-146b), 23212, 23223 (figs. 145a-145c, 145b) ; molars, nos. 23232, 23224, 23296a, 23294 (figs. 142a—142b, 143a, 143b, 148¢) ; and last molar, no. 23288 (fig. 147). All in Univ. Calif. Coll. Vert. Pal., all Univ. Calif. loc. 3269. 1921] Frick: Faunas of Bautista Creek and San Timoteo Cation 399 Characters.—The relatively large size, great transverse thickness, and general Pliohippus form. The transversely expanded wings and resulting bold appearance of the metaconid-metastylid column, and the convexity of the outer edges of the protoconid and hypoconid. Description.—The teeth are of much heavier proportions than the average of the former section. All of the specimens excepting no. 147 Figs. 142a to 147. ?Pliohippus veleee subform B. Large lower cheek teeth, occlusal views, X 1; inner views, X 14. Figs. 142a, 142b, molar, no. 23232. Fig. 1434, no. 23224; fig. 1438, no. 232964; fig. 148c, no. 23294. Fig. 144, P3, no. 23326. Figs. 145a, 145¢, premolar, no. 23212; fig. 145b, premolar, no. 23223, Figs. 146a, and 146), nos. 23285, 23295 (reversed). Fig. 147, Mj, no. 23288. Eden beds, California. 23212 (fig. 145a) are considerably worn. Certain of the more worn specimens are somewhat approached in appearance and size by the larger teeth of the preceding section and no more than a sexual differ- ence may exist. This is suggested by the presence of a worn molar, no. 23294 (fig. 143c) that below the point of greatest transverse thick- ness is no larger than certain teeth of the preceding section. 400 University of California Publications in Geology [ Vou. 12 MEASUREMENTS Premolars: No. 23212 No. 23223 24.2 mm. 26.3 mm. Anteroposterior diameter UMAMISViETS Cl GUAT CI OT eseeet ec enosee. serese eaeenen neers eases 15.4 15.5 Anteroposterior length of metaconid-metastylid CC{OY RUD 0a pao ee arenes Rec PRE Pe nae et uRe a RAE 13.8 15.1 Molars: No. 23295 No. 23232 Anteroposterior diameter, ccesgessscsseeeseccceeeereetereeeseese 25.8 24.5 Mimamsverse: diameter iiccc..se ce scceec ses sene rere eens 16 17.5 Anteroposterior length of metaconid-metastylid 14.5 15 CO Nh eee eee ee eee eee ee LOWER CHEEK TEETH, NEAR (?)PLIOHIPPUS EDENSIS These teeth are of narrow transverse diameter, and moderate size. Material.—Molars, no. 23296 (figs. 148a—148b), no. 23298 (fig. 150a), no. 24229 (fig. 150b); and last molars, nos. 23298, 23297 and 23291 (figs. 151la, b, c), all from general Univ. Calif. loc. 3269. All in Univ. Calif. Coll. Vert. Pal. a ES 150a 148b 151b Figs. 148a to 151b. ?Pliohippus edensis, n. sp. Narrow type of cheek teeth; occlusal views, X 1; outer views, X 1%. Figs. 148a, 148b, molar, no. 23296. Figs. 149a, 149b, molar, no. 24228. Figs. 150a, 150b, nos. 23298, 24229. Figs. 15la to 151c¢, M3, nos. 23291, 23298, 23297. Eden beds, California. Characters.—The medium size, accompanied by transverse narrow- ness of the crown, and the great convexity of the inner margin of the protoconid and hypoconid. Description.—Several of the teeth are considerably worn. The specimens all have the character of molars, being thickest transversely at the anterior corner, and having the deep production of the fold between the protoconid and hypoconid. A specimen representing 1921] Prick: Faunas of Bautista Creek and San Timoteo Caron 401 the average of these teeth might be considered as greatly worn, and on that ground referred to the smaller of the two foregoing typical series, were it not: (1) for the presence of other greatly worn molars already referred to that section; and (2) for tooth no. 23296 (figs. 148a-148b), which though long-crowned and comparatively little worn, illustrates the same characters seen in the other narrow teeth. Tooth no. 24228 (figs. 149a—-149b) shows a tendency to the even, oval form in the valley bounding the protoconid of the M; of the teeth described under subform A of P. osborni, from which it otherwise differs abso- lutely through lacking: (1) the great development of the fold between the protoconid and hypoconid; (2) the anteroposterior elongation of the metaconid-metastylid column; and (3) the great degree of flatness of the exterior faces of that more advanced tooth type. LOWER CHEEK TEETH OF PLIOHIPPUS, indeterminate Teeth of remarkably small size, and of uncertain form. Material—A premolar, no. 23292 (fig. 153); molars, nos. 23517 and 23290 (figs. 154, 152); and a last molar, no. 23227 (fig. 155). All from general Univ. Calif. loc. 3269. All in Univ. Calif. Coll. Vert. Pal. Figs. 152 to 155. Pliohippus, indet. sp. Lower cheek teeth of very small size. Fig. 152, molar, no. 23290; m, outer view, X %; occlusal view, X 1. Fig. 153, premolar, no. 23292, outer view, X 14; m, occlusal view, X 1; n, cross section, x 1. Fig. 154, molar, no. 23517, outer view, X 14; m, occlusal view, X 1. Fig. 155, Mj, no. 23227, outer view, X 14; n, occlusal view, X 1. Eden beds, California. 402 Unversity of California Publications in Geology [ Vou. 12 Description.—The specimens represent peculiar and individual phases of specialization. They are all long-crowned and are remark- able for their transverse narrowness and generally small size. A small, shghly worn premolar, no. 23292 (fig. 153), is of inter- esting and unusual type. -— OB; and this divided by the time gives a us the rate. Tf, on the other hand, the apparent transverse shift be not real, but is to be explained as due to an erroneous assumption of the immobility of the Mocho—Diablo base, much of the foregoing discussion deals with an imaginary complication. It is perhaps worth noting in connection with this uncertainty that, on the assumption that the apparent shift is real and that the elastic fling is equal on the two —OB AB sy a sides of the fault, then the creep derived from the formula 454. Umversity of California Publications in Geology [Vou. 12 agrees with the creep inferred from the displacement between surveys I and II for the controlling stations, Tamalpais, Chaparral, and Ross Mountain; whereas if the apparent shift is due to a migration of the primary base the values for the creep thus independently arrived at do not agree. Fort Ross Group.—The Fort Ross group of geodetic stations may also be reviewed to advantage in the light of the elastic rebound theory. There are twelve stations in this group, five on the east side and seven on the west of the San Andreas fault. The data necessary for their discussion are tabulated below: Displacement Date Distance between surveys Direction of from fault IT and III of Station Survey II Km. Meters displacement TDApb Velie pees aan eee new rare BPN 1891 0.4 W 2.33 139° Pinmacle Rock 2.2.22... 1891 1.6 W 2.47 158° SET OTSUAMEN OSS Maser sees ee eee tees 1891 1.9 W 2.50 147° Timber Cove 1.9 W 2.22 144° SUOY CMA NKONOE eee ee eee 3 2.6 W 1.78 144° Horseshoe ...... ‘ 2.9 W 1.48 137° Seely 12XoWialy, eee ee 86 3.2 W 2.01 138° JeWevaweyie eb ll ope see ee eae 8° 1.55 1.46 320° Dix ON ee 8° 1.8E Tai 316° Chaparral 1.8 E 1.34 328° Peaked Hill 2.0E 1.27 301° IGpWaWCE Ys sie eee ee Se 3 2.0 E ST 327° Azimuth of the fault 141°. In addition to the determinations above listed Chaparral was also located in 1856. In 1891 it was found to have moved 1.83 meters in the direction 173°, that is in a period of thirty-five years, or at the rate of .052 meters per year. This movement was doubtless shared by all the stations in this group. Of the seven stations to the west of the fault Pinnacle Rock is anomalous in the direction of its displacement between surveys II and III; but the other six are fairly consistent both as to direction and amount. The average of these six stations, 2.05 meters in the direction 141°, is therefore taken as a better expres- sion of the absolute displacement than the average of all seven. Of the five stations on the east side Peaked Hill is anomalous in direction, while the other four are consistent. The average of these four stations, 1.48 meters in the direction 323°, is therefore taken as a better expres- sion of the displacement than the average of all five. With these mean values we may construct a diagram illustrating the movements of the eround. In figure 9 let A be the position in 1891 of a small circle bisected by the San Andreas fault, aa’, and B the point to which it 1921] Lawson: The Mobility of the Coast Ranges of California — 455 had moved by strain creep up to 1906a. The fault had also moved from aa’ to bb’. At the time of the earthquake the small circle at B was severed and the two semicircles were displaced, one to the north- west and one to the northeast. They remained, however, on the line bb’. But the geodetic survey showed that the semicircle on the west side was at c and that on the east side at c’. The fault itself, therefore, just as in the case of the Tomales Bay group, apparently shifted from Fig. 9 Fig. 10 Fig. 9. Fort Ross group. A small circle located at A in 1891 on the San Andreas fault had moved .78 meters to B by strain creep up to 1906. By slip and rebound in that year one half the circle moved 1.43 meters to C and the other half 2.2 meters to D. Fig. 10. Point Arena group. A small circle located at A in 1891 on the San Andreas fault had moved .7 meters to B by strain creep up to 1906. By slip and rebound in that year one half the circle moved 2.48 meters to C and the other half 2.23 meters to D. the position bb’ to the position cc’; and cc’ is found to be practically parallel to aa’ and bb’. On the assumption that this shift is real, the actual sudden change of position at the time of the earthquake for points on the west side of the fault was from B to c, or 1.43 meters in the direction 124°; while the real movement on the east side was from B to c’, or 2.2 meters in the direction 333°. The total relative dis- placement by slip on the fault, thus determined as the mean of six stations on the west side and four on the east side is 3.5 meters. If, instead of taking the mean absolute displacement of the points on each side of the fault, I had used a curve such as is suggested by Hayford and Baldwin™ to determine the mean absolute displacement at the 12 Warthquake Report, p. 133. U.S.C. and G. 8. Rpt. 1910, App. 5, p. 184. 456 University of California Publications in Geology — [Vou. 12 fault, the total relative displacement would have been larger, since the amount of rebound by slip is a function of proximity to the fault. The relative displacement measured at the fault by this method is 5 meters, which checks well with 15 feet measured on offset fences, ete. The component of the apparent shift normal to the San Andreas fault is .44 meters, as compared with .57 meters for Chaparral when this station is considered alone. The distribution of the relative dis- placement on the two sides of the fault is, as before, indeterminate under the assumption of real shift, unless we invoke the hypothesis of equal elastic fling. If the elastic fling were the same on the two sides of the fault at the time of the slip of 1906, then the direction of the shift is 10° and its amount is .57 meters. Point Arena Group.—tThe Point Arena group of stations comprises four on the east side of the fault and six on the west. The data necessary for their discussion may be tabulated as follows : Kilometers Displacement Direction of from fault 1891-1906 displacement Station trace in meters 1891-1906 FEW 0: Sees eel eee ey Bee Ps 25 1.51 340° ro) OLB eg ee ieee ae a ei eee 5 E 1.52 324° Cp ear otter ores career n aee 3.8 E 83 329° ATE) ATTN g ee ean Sse ee es Pe cerca 3.9 E 719 329° PAT OT cers ce sect ee vate ve cote 7.6 W 2.54 161° ROUN CLAM? Wess tresee soe en eee eee 6.7 W 2.57 161° Hea Wes) MI) AVL i erence erry prerPer eere sie eeerian ee 6.8 W 2.78 159° Point Arena Lighthouse.............. 6.4 W 2.45 161° Arena Catholie Church ...............- 5.7 W 2.67 163° SHOCMAKG? cee 1.5 W 3.27 164° The directions of displacement on the west side are very consistent and average 161°. On the east side they are fairly consistent and average 330°. In considering this group I assumed that the rate of creep was the same as at Chaparral, and that the direction of creep was north. The direction of creep is somewhat more north for Chaparral than for Tamalpais; and if the direction changes the same amount between Chaparral and Arena it would be about north at the latter locality. I then plotted the record of each station in the manner that I have illustrated in the cases of Tamalpais and Chaparral. In this way I found the amount of displacement for each station from the position which it occupied, not in 1891, but in 1906a. The values for such displacements were then plotted in proper proportionate distances from the fault line and a smooth curve, practically a straight line, was drawn through the points as the locus of their positions. 1921] Lawson: The Mobility of the Coast Ranges of California 457 This was done for each side of the fault separately. As a result I found that a point close to the fault on the east side should have suffered an absolute displacement of 2.23 meters to the southeast, while a similar point on the west side should have suffered an absolute displacement of 2.43 meters to the northwest. A curve constructed in this way is superior to that suggested by Hayford and Baldwin for the purpose of estimating the relation of the amount of displacement to distance from the fault. With these values we may construct a diagram, figure 10, to illustrate the movements of the ground. Let A be the position of a small circle bisected by the fault in 1891, B the position of the same circle in 1906a by strain creep. After the slip of 1906 the western semicircle was found by the Geodetic Survey at C, which is 2.43 meters from B in the direction 156°; and the eastern semicirele was found at D, which is 2.23 meters from B in the direction 339°. There may be some doubt in this case as to the azimuth of the fault, since in this vicinity it leaves the coast and is supposed to curve easterly through about twenty degrees so as to connect with the similar feature at Shelter Cove in Humboldt County. But whatever the orientation may be the fault moved from A to B in the interval between 1891 and 1906. The absolute displacements of the two semicircles are very nearly equal in amount and opposite in direction; and it seems probable that the average azimuth of the fault in this vicinity is expressed by the line CD, the bearing of which is 157°. If this be so, the apparent transverse shift is so slight that it is probably non- existent. If the shift elsewhere is to be explained by the migration of the Mocho—Diablo base then this influence is unfelt at Arena, and it is worthy of note that the triangulation in the vicinity of Arena is not shown by Hayford and Baldwin'® to be directly connected with that base, though it is doubtless indirectly tied to it. The positions of the stations in the Point Arena group are dependent upon the Fisher— Cold Spring base, which is also assumed to have been unaffected by the crustal movements. But with the northerly strain creep at Arena as a necessary precursor of the faulting and elastic rebound in 1906, and the evidence of northerly creep of the station at Ukiah, it is difficult to concede the assumption of immobility of the Fisher—Cold Spring base. It may, however, have been advancing in the interval 1891-1906 and have sprung back in the latter year as far as it had advanced, so that the effect in locating points near Arena would have been the same as if it had not moved. 13 Karthquake Report, Atlas, map 24. 458 University of California Publications in Geology [Vou. 12 It is interesting to note that in the vicinity of Arena the elastic fling of the ground on the two sides of the fault was practically the same in amount, and that the total differential displacement, 4.66 meters, as determined geodetically, checks closely with the displace- ment of 15.5 feet at the fault measured on the ground by offset fences, ete. In the foregoing discussion of the facts brought out by the geodetic survey of the region north of the Golden Gate I have applied the theory of elastic rebound as rigorously as the facts will permit. The theory calls for a strained condition of the earth’s crust as a necessary preliminary to faulting. To account for this strain we must abandon the notion that the displacement, found to have occurred between surveys I and II, was a sudden movement which took place at the time of the earthquake in 1868. This notion was tentatively adopted by Hayford and Baldwin and affects many of the conclusions which they drew from the discussion of the geodetic data. The displacement whieh occurred between surveys I and II is here assumed to be the expression of a northerly strain creep, due to the drag of the crust riding on a suberustal flow. The amounts of displacement for several controlling stations and the dates of the surveys of these being known, we have the rate of creep due to accumulating strain, and this may be used to find the total slow displacement up to April 18, 1906. The position before the earthquake is thus known of points which, after the earthquake, were located geodetically, and the net displacement at the time of the shock is thereby ascertained. But it is known positively and independently of the geodetic survey that a portion of this net displacement was due to slip on the San Andreas fault and was therefore parallel to it. Another element of the net displacement was apparently due to a transverse shift which carried the fault plane with it, unless the Mocho—Diablo base had moved a corresponding amount. REGION SOUTH OF THE GOLDEN GATE The region south of the Golden Gate appears to have suffered a more complicated series of displacements than that to the north. Here we are confronted with evidence of greater variation of movement both as to amount and direction, with a dominance of the southerly com- ponent in the net result. Here, also, we have to reckon with the dis- placements which caused the earthquake of 1868 and possibly that of 14 Earthquake Report, vol. 1, p. 60. 1921] Lawson: The Mobility of the Coast Ranges of California 459 1865. The dominance of the southerly component suggests the disten- sion of the region for which Rothpletz and Wood have proposed independent and different explanations. In considering the geodetic data available for this region I shall continue to apply the elastic rebound theory and shall adopt the hypothesis that the results observed here are due to the operation of the same fundamental causes as in the region to the north of the Golden Gate. That is to say, I shall endeavor to show that the ascertained facts of displacement may be the consequence of the same northerly strain creep, due to subcrustal flow, as that which affected the region farther north, and that distension, in the sense of Rothpletz and Wood, may therefore be only apparent and not real. The movement of 1868.—Before taking up this discussion, however, I will state what appears to me to be the nature of the movement which caused the earthquake of 1868, since this conception will enter into the discussion as an essential hypothesis. The evidence as to what actually happened in 1868 in the way of earth movement is scant and unsatis- factory. It is certain that the Haywards fault opened as a gaping fissure at intervals for at least twenty miles southeastward from San Leandro. At some places it stayed open and had to be bridged.t® At other places it was sounded with a string and plummet but the bottom could not be reached.'® This open crack was not a feature of the alluvium at the base of the hills but was found in the rock of the hill slopes. There was no fault slip on the fissure, and the displacement of a few inches which affected fences, and which occurred slowly after the earthquake, is clearly referable to later adjustments, necessitated by the lack of support for the walls of the fissure. The Haywards fault thus behaved very differently in 1868 from the San Andreas fault in 1906. The open fissure is significant not of differential dis- placement as a relief from shear strain, but of relief from tension. It seems to prove conclusively that there was no northerly displacement of the valley of San Francisco Bay at the time of the shock, for in this event the crack would not have opened. It appears, moreover, that the earth wave which was generated by the displacement of the earth’s crust moved from north to south. Captain Peterson while in the vicinity of Robert’s Landing heard a great rumble off across the fields towards San Leandro (i.e., to the north). He looked quickly in that direction, and over a mile away 15 Op. cit., p. 444. 16 Op. cit., p. 441. 460 University of California Publications in Geology [Vou. 12 could see the great wave rapidly approaching. He rushed to the side of the road and had caught hold of the fence by the time the shock broke? Mr. J. A. Graves was in the field a mile or so south of Colma with his father. Looking north they saw first San Bruno Mountain bobbing up and down; then they saw the effect of the shock on a freight train between them and the mountain, and finally they felt the shock themselves and were thrown by it to the ground.*® These two bits of testimony, recording observation on both sides of San Francisco Bay, seem to me to prove that the earth wave was generated to the north of these observers and moved southward. In view of all the evidence, including personal testimony, open eracks and geodetic measurements, the most satisfactory hypothesis that can be formulated with regard to the direction of the sudden displacement of the ground in 1868 is that it was southerly. It was doubtless a rebound from elastic strain, and the relief from strain was doubtless effected by slip on a fault. There is no evidence of the outerop of this fault, and as the region is geologically well known it is fairly certain that it does not emerge at the surface, unless possibly south of Monterey Bay. I am constrained, therefore, to believe that the slip which caused the sudden southerly movement in 1868 took place on a lowly inclined fault deep in the earth’s crust. We thus have as our working hypothesis for the event of 1868: a slow suberustal flow in a northerly direction, generating a strain in the overriding crust, relief from this strain by rupture and slip on a flat fault, and the southerly rebound of the block above the fault, causing the earthquake. Thus explained the sudden movement of 1868 appears to differ from that of 1906 in the fact that it was an expression of the relief of the longitudinal strain, while the later movement was due to sudden relief from transverse strain. Summary statement of displacements.—In the region south of the Golden Gate, the displacements which were measured geodetically between 1854 and 1906 are, by this hypothesis, the resultant of the following separate and distinct movements: (1) A northerly strain creep persistent throughout the entire period covered by the surveys. (2) A southerly elastic rebound from the longitudinal strain which had developed up to 1868. (3) A southerly elastic rebound from the transverse strain by reason of shp on the San Andreas fault in 1906. 17 Op. cit., p. 448. 18 Op. cit., p. 445. 1921] Lawson: The Mobility of the Coast Ranges of California 461 (4) An expansive rebound which carried the San Andreas fault parallel to itself to the southwest, if we accept the assumption of the immobility of the Mocho—Diablo base. Rocky Mound.—The geodetic station Rocky Mound, situated 32 km. from the fault to the eastward, is on the border between the region to the south which participated in the sudden shift of 1868 and the region to the north, which did not. The border is naturally vague and in- determinate so that it is uncertain whether the station was displaced in 1868 or not. I shall therefore discuss both possibilities. The position of the station was determined in 1854, 1885, and in 1906p. Assuming first that the station was not displaced in 1868 the displace- ment of .5 meters in the direction 188° between 1854 and 1885 gives us a rate of strain creep of .016 meters per year. In figure 11, I, let Fig. 11, I. The path of Rocky Mound under the assumption of no displace- ment in 1868. Fig. 11, Il. The path of the same station if displaced in 1868. A represent the position of the station in 1854 and B its position in 1885. At the rate deduced the point would have been at C in 1906a. But after the earthquake it was found at D by the Geodetie Survey. If the station moved in 1906 by reason of the slip on the San Andreas fault, the direction of movement due to that cause must have been parallel to the fault, or in the direction 306°. There is thus an apparent transverse shift of about .25 meters, which may be real or may be explained as before by the migration of the Mocho—Diablo base. Secondly, we may assume that Rocky Mound was suddenly dis- placed to the south in 1868. In this case let A in figure 11, I, represent its position in 1854, B in 1885, and C in 1906p. Under this assumption there is no basis in the data for deducing the rate and direction of creep, and I shall therefore adopt the rate found at Tamalpais of .058 meters per year in the direction 168° for the pur- pose of illustrating the general path of the station under the hypothesis 462 University of California Publications in Geology [Vou. 12 of continuous stress and successive reliefs from the consequent strain. In the interval between 1854 and 1868 the station should have moved .058 > 14=—.812 meters in the direction 168° to the point F. In arriving at B in 1885 the station was creeping northerly and had been doing so since 1868p. It had thus moved in the direction 168° for seventeen years at the rate of .058 meters per year. This gives us the position of the station at D in 1868p. The line F'D is therefore the measure and direction of the rebound of 1868 for this station. This creep continued in the same direction from 1885 to 1906a and brought the station to E. From EF it rebounded to C in 1906. But the move- ment due to shp on the fault in 1906 was in the direction 306°, along the line bb’, and could only have arrived at C by a transverse shift, unless C be located too far south by reason of the assumption of immobility for the Mocho—Diablo base. This second assumption, that Rocky Mound participated in the sudden displacement of 1868, yields results which are consonant with the behavior of other stations in the region to the south, whereas the first assumption of stability in 1868 places it in an anomalous situation with regard to the behavior of stations north of the Golden Gate. Red Hill—Red Hill is 19 km. distant from the fault to the east- ward. Its position was determined in 1854, 1885, and 1906p. The displacements found by these surveys were: .65 meters in the direction 232°, between 1854 and 1885, and .30 meters in the direction 215° between 1885 and 1906p. These figures suggest that the direction of movement was away from the fault and nearly normal to its strike. This suggestion may, however, be fallacious and the station may have followed a devious path. To illustrate, let A, B, and C, figure 12, be the positions at which the station was found in 1854, 1885, and 1906p respectively. We may first follow the path of the station for the period after 1885. At this date the station was at B, moving northerly by strain creep. I shall assume the rate of this creep to be the same as that found at Tamalpais, or .058 meters per year. In the interval of twenty-one years between 1885 and 1906a the station must have travelled 1.22 meters and have been somewhere on the circle aa’, which is drawn from the center B with the radius 1.22 meters. If now the sudden movement in 1906 were wholly parallel to the fault, then the line cC, drawn through C in the direction 144°, would be the path of the station for that movement, and the point of intersection of cC with the circle aa’ would be the position of the station in 1906a. But the sudden movement of 1906 involved, besides the slip parallel to the 1921] Lawson: The Mobility of the Coast Ranges of California 463 fault, an apparent transverse shift whereby the fault was moved parallel to itself to the southwest. I shall, therefore, allow for this and assume that the station in 1906a was on the circle aa’ at D, a little to the east of the point of intersection of the line cC. Then the line DB is the azimuth of strain creep, and this is 163°. The exact position of D is uncertain, but its departure from c is doubtless a small quantity, and the position assigned to it will serve my present purpose, which is not to arrive at exact numerical expressions for the various displacements, but to develop a consistent hypothesis as to the Fig. 12 Fig. 13 Fig. 12. The path of Red Hill as determined by strain creep and the rebounds of 1868 and 1906. Fig. 13. The path of Loma Prieta as determined by strain creep and the rebounds of 1868 and 1906. general path of a station between 1854 and 1906p in the disturbed region south of the Golden Gate. But if BD be the direction of strain ereep then the path of the station from 1854 to 1868a must have been on the same azimuth. It is fair to assume, therefore, that in this interval of fourteen years the station moved .085 * 14—.812 meters in the direction of 163°. Thus we have the position of the station just prior to the sudden movement of 1868, at E. Similarly after the earthquake of 1868, the station moved from F to B, .98 meters in the direction 163°, so that the position of the station immediately after the sudden movement of 1868 is also known. The line EF gives us, therefore, both the amount and the direction of that sudden movement, which was 1.68 meters in the direction 321°. Thus, by way of sum- mary, the path of the geodetic station Red Hill between 1854 and 1906p was from A to E by slow strain creep, from EF to F by sudden rebound in 1868, from F' to D by renewal of strain creep, and from D to C by sudden rebound in 1906. The last movement from D to C 464 University of California Publications in Geology [Vou 12 was chiefly parallel to the San Andreas fault, but on the assumption of transverse shift there was also a small component of movement normal to the fault. Loma Prieta.—Let us next consider Loma Prieta, for which we have surveys in 1854, 1884, and 1906p. The geodetic data are: between 1854 and 1884 the station had been displaced 3.03 meters in the direc- tion 307° and between 1884 and 1906 an additional .97 meters in the direction 303°. I shall assume that the persistent northerly strain creep was in the same direction as that adopted for Red Hill, or 163°, although it may have been a few degrees more to the west; and the rate of this strain creep I shall again take at .058 meters per year. In figure 13, let A be the position of the station in 1854, B its position in 1884, and C in 1906p. By 1868a it would have moved to D, or .812 meters in the direction 163°. In arriving at B in 1884 the station must have moved by strain creep in the direction 163° from the point to which it was suddenly shifted in 1868. In 1868p, there- fore, Loma Prieta was at EH, .058 * 16=—.928 meters from B. The line DE is the measure of the sudden movement of 1868. This is 4.57 meters in the direction 320°. After 1884 the station continued its northerly migration until 1906a, when it had arrived at I’, 1.27 meters from B in the direction 163°. From F it rebounded, at the time of the earthquake, parallel to the San Andreas fault, which here has the strike of 135°, and was therefore on the line bb’. But after the earthquake it was found at C; so that the line bb’ was apparently suddenly shifted parallel to itself to C. This shift, measured normal to the fault, amounts to .40 meters, and is the same apparent transverse shift that was recognized in the stations north of the Golden Gate. These last two movements, one parallel to the fault, the azimuth of which is known but the amount not, and the other, of which only the component normal to the fault is known, together make up the net sudden displacement of the station on April 18, 1906, from F to C, or 2.10 meters in the direction 325°. Thus between 1854 to 1906p, Loma Prieta moved first by strain creep from A to D, then by rebound from D to E, then by renewed strain creep from E to F’, and again by rebound from F' to C. Gradient of displacement.—It is noteworthy that while the sudden movement of Red Hill in 1868 was 1.68 meters to the southeast, that of Loma Prieta was 4.57 meters, or 2.72 times as much. This fact consists with the hypothesis that the sudden movement which caused the earthquake of 1868 was confined to the region south of the Golden 1921] Lawson: The Mobility of the Coast Ranges of California 465 Gate. If this be so, then there must be a locus in the vicinity of the Golden Gate, transverse to the direction of that movement, on which the movement was zero. If as I have already suggested, the earthquake of 1868 was caused by rebound on a flat fault, then the measure of that rebound, being the relief from elastic compression, would be progressively and regularly greater from north to south. If this be so then we may locate approximately the zero point of the slip on the flat fault. For we can take the measures of the rebound at Loma Prieta and Red Hill and therefrom construct a gradient, the rebound being proportional to the southerly departure of the stations from the zero point of slip. Thus in figure 14 let AB represent the distance 50 miles Fig. 14. Gradient of displacement by elastic rebound in 1868 between San Bruno Mountain and Loma Prieta. between Red Hill and Loma Prieta, and make AA’ and BB’ propor- tional to the sudden shifts of these stations in 1868. Then the line A’B’ affords the measure of the same shift for any other station to the north of Loma Prieta. The zero point of shift is thus found to be at San Bruno Mountain, fifty miles from Loma Prieta. The shift of 1868 at Black Mountain, CC’, was 2.67 meters, and at Pulgas West Base, DD’, was 1.54 meters. The shift at Sierra Morena was the same as that at Red Hill. Black Mowntain.—Using now this inferential information we may arrive at the movements of those stations which were located by surveys I and III but not by II. In the ease of Black Mountain let A in figure 15 be the position of the station in 1854 and B the position in 1906p. Between 1854 and 1868 the movement would have been by strain creep .812 meters in the direction 163° to C; thence by rebound 2.67 meters in the direction 320° at the time of the earthquake of 1868 to D; thence between 1868 and 1906a, by renewal of the strain, 2.2 meters in the direction 163° to H; thence by rebound in 1906 south- easterly along bb’ parallel to the San Andreas fault an unknown dis- tance compounded with an apparent transverse shift. which brought it to B. The component of the transverse shift normal to the fault is .78 meters. 466 University of California Publications in Geology — [ Vou. 12 Pulgas West Base.—Pulgas West Base was located in 1853 and again in 1906p, but not in the interval between. In figure 16 let A be the earlier position and B the later. In the interval 1853-68 the station moved .87 meters in the direction 163° by strain creep to C; thence by rebound in 1868 1.54 meters to D; thence by renewed strain creep 2.2 meters to EH in 1906a; thence, by rebound, southeasterly parallel to the San Andreas fault an unknown distance, on the line bb’, com- pounded with an apparent transverse shift which brought it to B. v b N b E Cc b N A C = c A b! D >! i B A Fig. 15 Fig. 16 Fig. 17 Fig. 15. The path of Black Mountain as determined by strain creep and the rebounds of 1868 and 1906. Fig. 16. The path of Pulgas West Base as determined by strain creep and the rebounds of 1868 and 1906, Fig. 17. The path of Sierra Morena as determined by strain creep and the rebound of 1906. The component of the transverse shift normal to the fault is in this case 1.33 meters, an exceptionally large figure, suggestive of a slight error in the azimuth AB. Sierra Morena.—Sierra Morena on the west side of the fault was located in 1883 and again in 1906a. It is situated 4.3 km. from the fault. In figure 17 let A be the earlier position and B the later. In the interval of twenty-three years between 1883 and 1906qa the station would have moved .058 & 23 —1.33 meters in the direction 163° to C. At the time of the earthquake in 1906 it moved by rebound northerly parallel to the fault on the line bb’. But after the earthquake it was found at B. The line bb’ was apparently shifted parallel to itself to B, and the component of this transverse shift normal to the fault is .69 meters. Mt. Toro.—Mt. Toro, situated on the west side of the San Andreas Rift but south of the region of slip in 1906, probably did not move at the time of the earthquake of that year. At least there is no evidence, or even suggestion, that it did. The station was located in 1885 and 1921] Lawson: The Mobility of the Coast Ranges of California 467 again in 1906p. In the interval of twenty-one years it was found, on the assumption that Santa Ana had not moved, to have been displaced 95 meters in the direction 168°. This displacement, I take it, represents strain creep unaffected by subsequent rebound. The rate of strain creep is, therefore, .045 meters per year. Gavilan.—Gavilan is also south of the region of shp on the San Andreas fault in 1906, and probably suffered no rebound in that year. Its position was located in 1854 and in 1906p, but not in the interval c D Fig. 18. The path of Gavilan as determined by strain ereep and the rebound of 1868. between. Between these dates it was found to have been displaced 5.2 meters in the direction 309°. The path of its movements may be found under the hypothesis here adopted by use of the accompanying diagram. In figure 18 let A be the position in 1854 and B that in 1906p. Using the rate and direction of strain creep found at Toro, namely .045 meters per year in the direction 168°, the station would have arrived at C in 1868a, .812 meters from A in the direction 168°. The sudden shift of 1868 is found, by the gradient above referred to, to be 7.20 meters; and this was probably in the same direction as the same movement of Loma Prieta, or 320°. This would bring the station in 1868p to D. From D, moving in the direction 168°, the station by strain creep would have arrived in 1906 at H, 1.71 meters from D, which checks very closely with the position at which it was actually found at B, only about .1 meter away. The closeness of the check is 468 University of California Publications in Geology [Vou. 12 probably a coincidence, for we are now in a region where the geodetic data are less certain than they are to the north. The amount of dis- placement of Gavilan is postulated on the immobility of Santa Ana. But while Hayford and Baldwin’? appear to be justified in their assumption that Santa Ana suffered no displacement in 1906, it is probable that this station has participated in the strain creep of the region, and it is not improbable that it moved suddenly in 1868. The position of Santa Ana was determined in 1852 and its change of position between that date and 1906p, whether by strain creep or rebound, would seriously affect the measure obtained for the displace- ment of Gavilan. Santa Cruz and Point Pinos—Santa Cruz and Point Pinos are somewhat anomalous, particularly in the azimuth of their direction of displacement. The uncertainty as to the movements of Santa Ana, however, renders futile any attempt to discuss the behavior of the stations at these places. Under certain plausible assumptions as to the movements of Santa Ana between 1852 and 1906p, consistent with the hypothesis of strain creep and rebound, a large part of the supposed displacement of Point Pinos and Santa Cruz might be unreal. If, contrary to probability, Santa Ana were immobile between 1852 and 1906p, then the ascertained displacements of both Point Pinos and Santa Cruz may be made consistent with the displacements of other points nearer the San Andreas fault by assuming a larger azimuth for the direction of rebound in 1868. The Colma Group.—The behavior, in 1906, of the group of geodetic stations near Colma, comprising Flat Road, False Cattle Hill, and San Pedro Rock to the west of the San Andreas fault and Black Bluff, Black Ridge, and San Bruno Mountain to the east, is anomalous. The anomaly, however, is not of the same kind on the two sides of the fault. On the east side of the fault it appears in the smallness of the amount of displacement; while on the west side, although the amount of displacement is approximately normal, the direction of that dis- placement has a notable component toward the fault. Both anomalies may perhaps be referred to a common cause inherent in the geological structure of this part of the region. Immediately to the east of the San Andreas fault, between it and San Bruno Mountain, is a deep wedge of late Tertiary sediments, comprising the Merced and later formations, which are relatively incoherent and inelastic.2° Such 19 Harthquake Report, vol. I, p. 130. 20 See U.S. G. 8S. 15th Ann. Rpt., pp. 459 et seq.; also folio 193, pp. 14-16. 1921] Lawson: The Mobility of the Coast Ranges of Califorma 469 sediments are incapable of accepting a condition of elastic compression. Any stress applied to them would not generate a condition of strain, but would be dissipated in plastic deformation. It is, therefore, highly probable that although the firm rock below the Merced may have been in a condition of strain, this strain could not have been communicated to this body of sediments. They, therefore, lacked in large measure the ability to rebound when the strain of the region was relieved by the slip on the San Andreas fault. It is true that they might have been carried south by the elastic rebound of the underlying firm rocks, but, owing to the suddenness of this rebound, the principle of inertia would operate to restrain movement at the surface, and the tendency would have been largely quenched in plastic deformation. It is thus comprehensible that in the Merced terrane the condition of transverse strain prerequisite to rebound was lacking, and that, therefore, in the upper mile of the crust the transverse strain could not be transmitted to the firm rocks of San Bruno Mountain and Black Ridge, so that their tendency to rebound was also feeble. The eastward component of motion of the ground on the west of the fault may be explained by a deformation of the fault plane itself, due to a slight east-west condensation of the wedge of Merced sedi- ments. At the time of the slip in 1906 the large east-west component of the free elastic force on the west side of the fault may have been sufficient to stove in the fault plane towards the feebly resistant wedge of inelastic Merced strata. APPARENT DISTENSION Certain phenomena of apparent distension call perhaps for a special discussion. Hayford and Baldwin*' first directed attention to the fact that in the interval between surveys I and III there was an increase of 3 meters in the distance between Tamalpais and Black Mountain, of 2 meters between Black Mountain and Loma Prieta, of 1.2 meters between Loma Prieta and Gavilan and of 3 meters between Santa Cruz and Point Pinos. The last mentioned increase is somewhat doubtful owing to the assumption of immobility of Santa Ana, the controlling station, but there seems to be no reason for doubting the reality of the others. This increase of the distances between geodetic stations was taken by both Rothpletz and Wood as significant of a deep-seated distension of the region. The phenomena are, however, 21 Op, cit., pp. 132-133. 470 University of California Publications in Geology [Vou. 12 susceptible of satisfactory explanation on the hypothesis of a persistent northerly strain creep throughout the entire region, with a southerly rebound in 1868 of that part of it south of the Golden Gate. This hypothesis involves the notion of an elastic prism released from com- pressive drag so as to rebound in one direction only. The measure of rebound will increase regularly in an arithmetical ratio from the fixed or zero point toward the free end. Thus if Tamalpais were unmoved in 1868, the rebound from compression of the block to the south would increase the distance between that station and Black Mountain. For points north of Black Mountain, but south of the locus of zero move- ment in 1868, the increase of distance from Tamalpais would be less, and for points south greater. There must be, of course, a limit to Fig. 19. Effeet of relief of longitudinal strain on a lowly inclined fault. this expansive rebound, but at present we do not know where it is, except that it is beyond Gavilan to the southward. The arithmetical ratio of increase of the measure of rebound applies only to the sudden movement of 1868 and not of course to the geodetically measured distances, since the increase of distance is due to the rebound of that year less strain creep between surveys I and III plus the rebound of 1906 for Black Mountain and Loma Prieta, but without any increment in 1906 for Gavilan. The notion that the entire region is subject to a persistent north- erly flow stress, while only the part of it south of the Golden Gate rebounded in 1868 on a presumed flat fault, implies a residual strain in the region north of the Golden Gate. That this is mechanically possible may be appreciated by reference to the diagram, figure 19. Let AB represent the line of demarcation between the zone of flowage and the zone of rupture. The arrows C and D represent the directions of stress and strain respectively, and aa’ is a flat fault upon which a slip has just occurred. This fault intersects AB at E. Below EF the fault cannot persist as such into the viscous zone. The slip, therefore, is only effective for the portion of the overriding crust to the right of E and above aa’. In this segment of the crust the rebound takes place. To the left of E above AB the stress has operated continuously 1921] Lawson: The Mobility of the Coast Ranges of California 471 and the strain is still maintained. To the right of H between AB and aa’ the stress has also operated continuously and the strain is main- tained. In the portion of the crust that has been relieved of strain an expansion has occurred, the measure of which is proportional to the distance from E, the zero point of the rebound in a given section. In the region south of the Golden Gate the locus of EF passes through San Bruno Mountain. SUMMARY I have now reviewed, in rather summary fashion, the results of the geodetic surveys and have interpreted them in the light of the elastic rebound theory of faulting. The working hypothesis of the paper is the validity of the theory, which states that faults and consequent earthquakes are due to sudden relief from compressive strain by rupture, or by movement on old rupture planes. In the seismic region of the middle Coast Ranges the causal stress of this strain is probably a northerly slow suberustal flow which is indicated by the displacement of several geodetic stations in the interval between surveys I and II. The more important of these stations are to the north of the Golden Gate and to the east of the San Andreas fault. In each case, the amount of displacement and time interval being known, the rate of movement is ascertained. The movement itself is interpreted as the expression of strain creep due to the northerly stress. The northerly migration of the Ukiah station of the International Latitude Service, and of Lick Observatory, sustains the hypothesis of a northerly strain creep which affects the whole region. The strain generated by the northerly stress has a twofold distribution: (1) A longitudinal strain, opposed in direction to the general stress, which is relieved by lowly inclined, deep faults having a strike normal to the direction of stress; and (2) a transverse strain, due to the unequal distribution of the stress in the horizontal sense, which is relieved by vertical faults having a strike oblique to the direction of stress. The longitudinal strain for the portion of the region south of the Golden Gate was relieved at the time of the earthquake of 1868, while the transverse strain for the whole of the region considered was relieved by a slip on the San Andreas fault in 1906. The absence of any evidence of rebound in 1868 in the territory north of the Golden Gate is the warrant for assuming that none occurred. The hypothesis that the rebound of 1868 in the territory south of the Golden Gate was south- erly, and that the measure of this rebound increased regularly to the 472 University of California Publications in Geology [Vou. 12 southward from a locus of zero movement near San Francisco, agrees with and explains many facts. In the absence of the outcrop of any vertical fault, functional at that date, we are forced to assume slipping on a fault of low dip which is not known to emerge at the surface. This conclusion and the application of the principle of elastic rebound, enables us to explain practically all the facts without recourse to the notion of distension, which was first suggested by Hayford and Bald- win, tentatively accepted by myself, and finally adopted by Rothpletz and Wood. The distension, as regards at least the causal flow, becomes unreal, and all the phenomena are accounted for by the operation of a persistent northerly suberustal flow, generating in the overriding crust a state of strain, which is relieved from time to time by rebound slips on faults, both highly inclined and flat, each slip causing an earthquake. The fundamental weakness in the data upon which the discussion is based is the uncertainty as to the immobility of the geodetic base Mocho—Diablo. If it be assumed, with Hayford and Baldwin, that this base was unaffected by the strain creep, then we are forced to recognize a transverse shift of the region supplementary to the slip on the San Andreas fault in 1906. If the Mocho—Diablo line upon which the triangulation was based migrated northerly then the apparent transverse shift becomes unreal, and is easily explained by that migration. But if the Mocho—Diablo base participated in the strain creep then the quantities for the rate of strain creep and northerly rebound on the west side of the San Andreas fault would in several eases be increased, while the quantities for the southerly rebound on the east side of the fault would in most, if not all cases, be diminished. In view of this uncertainty I have sought throughout the paper merely to develop the general consequences of the validity of the elastic rebound theory, rather than to arrive at precise measures of either strain creep or rebound. One gratifying thing about the hypothesis of persistent northerly strain creep as a local manifestation of the principle of elastic rebound is that it is susceptible of verification or disproof. As the work of the U. S. Coast and Geodetic Survey proceeds we will know with exactness the geographical position of many points in the Coast Ranges of California. In the lght of the elastic rebound theory of faulting it is no longer permissible to assume that changes in position, such as were discovered after the earthquake of 1906, are due wholly to sudden shifts which occur at the times of earthquakes. The theory teaches that sudden shifts can occur only after the accumulation of 1921] Lawson: The Mobility of the Coast Ranges of California 473 strain to a limit and that this accumulation involves a slow creep of the region affected. In the long periods between great earthquakes the energy necessary for such shocks is being stored up in the rocks as elastic compression. The relief from such compression by fault slip of course indicates a sudden shift of ground, and therefore a sudden change of geographic position, which is a matter of great concern to the Coast and Geodetic Survey. But the changes in latitude and longitude due to the preliminary strain creép are not less in magnitude and of no less concern to the Survey than the sudden shifts at times of faulting and earthquake. In order to render the surveys consistent and to make proper adjustments, it will be necessary to ascertain both the rate and direction of strain creep in this mobile portion of the earth’s crust. In the course of their regular duties, therefore, officers of the Survey will acquire the data necessary not only to establish on a firm basis the fact of strain creep, but also its rate and direction, with their variations. INDEX Acknowledgements, 2, 27, 283, 425, 426, 438. Africa, 285. Agassiz, L., 245. Agriotherium (Hyaenarectus) schnei- deri, 341. Alachua fauna, 287. Alaska, 27. Alticamelus, 361. giraffinus, 362. procerus, 361, 362. Amauropsis alveata, 10. Anderson, F. M., 242. Anderson, R., 242. Antelope, 283. Antelopinae, 288. Antilocapra?, one or more species, 300; plate showing, 301. n. sp., 380; description of, 380; plates showing, 379, 380, 382. Antilocapra or Neotragoceros, one or two indet. sp., 293. Antilocapridae, 379. Arctotherium, 341. Arnold, D., 242. Arnold, R., 9, 11, 16 footnote 11, 21 footnote 12, 242, 244. See also Arnold and Hannibal. Arnold and Hannibal, 245. Ashley, G. H., 242. Astrodapsis, 28, 42, 78; phylogenetic tree for genus, 43. altus, 44, 80; plate showing, opp. 182. antiselli, 42, 78, 81; plate showing, opp. 190. arnoldi, 83. arnoldi, 31. arnoldi, 83; plate showing, opp. 194. crassus, 44, 85; plates showing, opp. 198 and 200. depressus, 85; plate showing, opp. 198. fresnoensis, 44, 85, 87; plate showing, opp. 198. peltoides, 85, 88; plate showing, opp. 182. spatiosus, 44, 89; plate showing, opp. 196. brewerianus, 36; plate showing, opp. 178. diabloensis, 37, 79, 92; plate showing, opp. 178. californicus, 84, 85, 93; plate show- ing, opp. 188. cierboensis, 42, 79, 94; plate show- ing, opp. 180. coalingaensis, 45, 96; plate show- ing, opp. 184. grandis, 45. cuyamanus, 45, 97; plate showing, opp. 190. fernandoensis, 42, 98; plate show- ing, opp. 200. grandis, 97, 100; plates showing, opp. 186 and 188. jacalitosensis, 45, 101, plate show- ing, opp. 192. major, 31, 44, 102; plate showing, opp. 182. margaritanus, 42, 103; plate show- ing, opp. 196. ornatus, 42, 105; plate showing, opp. 194. (?)pabloensis, 95, 106; plate show- ing, opp. 180. peltoides, 88. perrini, 129. scutelliformis, 45, 107; plate show- ing, opp. 194. tumidus, 31, 42, 81, 108; plate showing, opp. 180. cierboensis, 94. whitneyi, 31. whitneyi, 98, 111; plates showing, opp. 184 and 186. Aucella piochi, 8. Auchenia, 356. Auriferous gravel flora, 251. Baker, C. L., 248. Baldwin, see Hayford and Baldwin. Barstow upper Miocene, 248. Basalt of Franciscan series, 7; lacco- lithic structure, 7. Batrachians of Rancho La Brea, 249. Bautista Creek, 283. Bautista Creek Badlands, 281; loca- tion of, 289; map showing, 281. — Bautista deposit, conditions of depo- sition, 291; materials of, 291; occurrence of fossils in, 291; Pleistocene fauna in, description of, 293. Bear, hyaenarctid, 283. Big Pine Mountain, 4. Birds, fossil, of the Pacifie Coast region, 248. Black Mountain, geodetic station, 465. Blanco deposits, 287. ‘“Blossom,’’? voyage of, 237. Breynia, 33. Brissopsis californica, 148. Buwalda, J. P., 248. Caenopus occidentalis, 271. Index Caenopus? or Diceratherium?, 271; plate showing, 271. Calaster, 130; phylogenetic tree for subgenus, and Dendraster genus, 47. interlineatus, 32, 35. oregonensis, 32, 35, 132. major, 132. California, during Pliocene time, 285; earthquake of 1906, 432; Lower, 27; Gulf of, 32. Camarodonta, 56. Camel, 283. Camelid, 293. Camelid?, 322. sp., 295; compared with Camelops from Rancho La Brea, 295; plates showing, 295, 321, 369. Camelidae, 356; plate showing, opp. 420. Camelops, 295, 356. Camelus americanus, 361. bactrianus, 361. dromedarius, 361. hesternus, differs from Plauchenia merriami, 362. sivalensis, 363. Camp, C. l., 249. Canidae, 341. Canis?, 341; plate showing, 340. Capromeryx, 283; (?) sp., 293; com- pared with C. minor from Rancho La Brea, 300; plate showing, 200. minor, 300. Carnivores, 248. Carrizo Creek, 33. Cassidulidae, 1388. Cassidulus, 29, 138. californicus, 138. (thynchopygus) californicus, 138; plate showing, opp. 230. ellipticus, 14, 139; plate show- ing, opp. 230. lyellt, 142. mexicanus, 140; plate showing, opp. 230. patelliformis, 140. ynezensis, 14, 140, 141; plate showing, opp. 230. Cat, 250, 283. Catopygus, 142. Catopygus (?), 29. cajonensis, 143; plate showing, opp. 232. californicus, 142; plate showing, opp. 232. Causal stress, hypothesis of, 435. Cedar Mountain, 248. Centrechinoida, 56. Centrechinoidea, 36. Cephalopoda, 250. Cervid?, 322; plates showing, 299, 322. Cervidae, 378; plate showing, 378. Cetaceans, 250. Chanac-Etchegoin, 287. Chandler, A. C., 249. Chaparral, geodetic station, 436; in- terpretation of data, 449; move- ments of, 446. Characters of Mylodon Harlani, 426. Cherts (shales and) of the Monterey group, 19. Chico rocks, 8. Cidaridae, 52. Cidaris, 28, 52. branneri, 52. indet. sp., 55. lorenzanus, 52; plate showing, opp. 158. martinezensis, 53; plate showing, opp. 158. merriami, 53; plate showing, opp. 158. sp. a, 54 sp. (d), 53. tehamaensis, 54; plate showing, opp. 158. thouarsii (?), 54. Cidaroida, 52. Cinnabar, 7, 18. Citellus, 273. beecheyi fisheri, 272. Claremont fault, 289. Clark, B. L., 26, 243, 249, 267. Clark, W. B., 241. Climatie conditions indicated by the Echinoid fauna, 34. Clypeaster, 30, 58. bowersi, 58; plates showing opp. 162 and 164. carrizoensis, 59; plate showing, opp. 166. deserti, 60; plate showing, opp. 166. ? (Echinarachnius) brewerianus, 91. gabbi, 69. rotundus, 60. Clypeastridae, 58. Clypeastrina, 37, 58. Coalinga, 32. Coast Ranges, California, creep of the Middle, 439; mobility of the, 431; structure of, 16. Colma group of geodetic stations, 468. Colorado desert, 32. Condon, T., 246. Conglomerate, Oakland, 8. Conrad, T. A., 26, 239. Cooper, J. G., 241. Cope, E. D., 246. Corals, 245. Cretaceous, 17, 31. Cretaceous and Cenozoic Echinoidea of the Pacific Coast of North America, 23. Index Cretaceous system, 8; of the Pacific Coast, 243; Cretaceous and Ter- tiary floras, 251. Daggett, F. 8., 426. Dall, W. H., 241, 244. John Day region of Oregon, 246. Dendraster, 28, 46, 113; phylogenetic tree for genus, and Calaster sub- genus, 47, fig. 5. arnoldi, 31, 46, 113; plate showing, opp. 208. ashleyi, 32, 115; plate showing, opp. 206. inezanus, 15. ynezensis, 116; plate showing, opp. 224. (Calaster) interlineatus, 68, 131; plate showing, opp. 222. ‘oregonensis, 36, 68, 132; showing, opp. 218. gibbosus, 134; plate showing, opp. 218. major, 134; opp. 220. coalingaensis, 45, 46, 117; plate showing, opp. 208. diegoensis, 119. diegoensis, 47, 120; plates show- ing, opp. 210 and 212. venturaensis, 48, 120; plates showing, opp. 210 and 212. excentricus, 30, 45, 119, 121; plates showing, opp. 214 and 216. gibbsii, 32, 122; plate showing, opp. plate plate showing, 202. humilis, 32, 46, 124; plate show- ing, opp. 202. hesperis, 46, 125; plate showing, opp. 204. gibbosus, 126; plate showing, opp. 204. (?) interlineatus, 131, 134. jacalitosensis, 46, 126; plate show- ing, opp. 202. oregonensis, 132. pacificus, 120, 128; plate showing, opp. 218. perrini, 46, 115, 129; plate showing, opp. 208. Denton, W., 247. Dice, L. R., 248. Diceratherium beds, 270. Diceratherium? or Caenopus?, 271. Dickerson, R. E., 248, 245. Dicotylinae, 350. Dinarctotherium merriami, 342. Displacement, maximum, at fault trace, 453; in region south of Golden Gate, 460; gradient of, south of Golden Gate, 464. Distension, 440, 459, 472; apparent, 469. [435] Distension theory of earthquakes, 433. Drag, term comprehensive of two dis- tinct phenomena, 440. Dyson, F. W., 436. Early Tertiary vertebrate fauna from the southern Coast Ranges of California, 267. Earthquake of 1868, 471; cause of, 445; nature of, 459. Earthquake of August 2, 1903, 439. Earthquake of 1906 (California), 435; mechanies of, 432. See also Causal stress; Suberustal flow. Echinanthus (Clypeaster?) testudi- narius, 59. Echinarachnius, 113. ashleyi, 115. brewerianus, 91. excentricus, 121. fairbanksi, 66. gabbi, 69. gibbsii, 117, 122. norrisi, 75. Eehini, Pacific Coast, 35. Echinidae, 56. Echinodiscus (?) perrini, 129. Echinoid fauna, climatic conditions indicated by the, 34. Echinoidea, 52. Echinoidea, Cretaceous and Cenozoic of the Pacific Coast of North America, 23. Eehinoids, 245. Echinus purpuratus, 58. Eden, 283. Eden formation, 335; location of ex- posure of, 335; occurrence of fos- sils in, 337; type of materials in, 335; fossil localities in, 339; pliocene fauna of, 339. Edentata, 349. Edentates, 248. Elastic rebound theory, 431, 432, 434, 435, 458; longitudinal and trans- verse strain, 443-445, 469; possi- bilities of transverse shift, 440. Eldridge, G. H., 9, 11, 242. Elsinore Quadrangle, 282; ing, 282. Encope, 30, 136. californica, 137. tenuis, 136; plates showing, opp. 224 and 226. : English, W. A., 244. Eocene, 31; series, 9; 242, Epiaster, 143. depressus, 143, 145; plate showing, opp. 232. Equidae, 382; plate showing, opp. 422. map show- faunas, 143, Index Equus, 250, 283. bautistensis, 289, 324. n. sp., 293, 302; characters of, 303; description of, 303; limb elements of, 308; lower den- tition of, 306; plate showing, 304; mandible of, 306; plate showing, 305; compared with mandible of E. occidentalis, 306; of E. scotti, 306; plate showing premaxillary, 306; teeth compared with teeth of E. caballus, 306; of E. com- plicatus, 311; of E. fraternus, 311; of E. idahoensis, 310; of E. namadicus, 310; of E. nio- barensis, 311; of E. occiden- talis, 308; of E. scotti, 308; of E. sivalensis, 310; of E. stenon- sis, 310; of Pliohippus prover- sus, 309; upper dentition of, plates showing, opp. 302 and 414. caballus, 303. complicatus, 311. fraternus, 311. giganteus, 289, 327. idahoensis, 289, 310. namadicus, 310. niobarensis, 289, 311. occidentalis, 289, 303 pacificus, 289, 308. scotti, 289, 306. sivalensis, 310. stenonsis, 310. Etchegoin Pliocene fauna, 244. Etchegoin, Upper, 31. Exocyecloida, 36, 58. Extinct Vertebrate Faunas of the Badlands of Bautista Creek and San Timoteo Canon, Southern California, 277. Fairbanks, H. W., 242. Fanglomerates, 12; term applied to material in San Timoteo deposit, 318. Farallon, geodetic station, 436; in- terpretation of data, 449; move- ments of, 448. Fault, Haywards, 459; Little Pine, 17, 18; Redrock, 17; San An- dreas, 443; Santa Ynez, 11, 20. Fault breccia, 440. Fauna, Bautista Pleistocene, descrip- tion of, 293; Cenozoie of the West Coast, 244; Echinoid, eli- matic conditions indicated by, 34; Eden Pliocene, 339; Etchegoin Pliocene, 244; Manix, 248; Mar- tinez, 243; Pleistocene, Rancho La Brea, 247; Pliocene, 244; San Pablo, 244; San Timoteo Plio- cene, 320. [436] Faunas, Eocene, 243; Tertiary, 242. Felis?, 341; plate showing, 340. Fernando formation, 15. Fernando Pliocene near Newhall, 244. Fibulariidae, 61. Flora of the auriferous gravels of California, 251; Mesozoic, 251; Puget, 251. Floras, Cretaceous and Tertiary, 251. Florida Alachua, 287. Fontaine, W., 251. Fort Ross group of geodetic stations, 454. Fossil birds of Pacifie Coast, 248. Fossil fish fauna of California de- scribed by Agassiz, and Jordan, 245, Fossil localities for Bautista fauna, 293. Fossil Lake Pleistocene of eastern Oregon, 247. France, 248. Franciscan series, 6; basalts of, 7; structure of the, 17. Frick, C., 250, 277. Furlong, E. L., 247, 248, 267. Gabb, W. M., 239. Gavilan, geodetic station, 467. Geodetic stations, lists of names, 450, 454, 456. See also Black Moun- tain, Chaparral, Colma group, Farallon, Fort Ross group, Gav- ilan, Loma Prieta, Mocho Diablo, - Mount Toro, Point Arena group, Point Pinos, Pulgas West Base, Rocky Mound, Ross Mountain, San Andreas, Santa Cruz, Sierra Morena, Sonoma, Tamalpais, To- males Bay group, Ukiah. Geodetic surveys, 435. Geology of a Part of the Santa Ynez River District, Santa Barbara County, California, 1; map show- ing, opp. 6. Gidley, J. W.; 248. Golden Gate, apparent distension of region south of, 469; gradient of displacement south of, 464. Gouge on the San Andreas fault, 442. Great Basin Province, 247. Ground-sloth, 283. Gulf of California, 32. Hannibal, see Arnold and Hannibal. Hapalops, 350. Harrison, Lower, 270. Hawver cave, 247. Hayford and Baldwin, 433, 435, 457, 469. Haywards fault, 459. Helix, 269. Hemiaster, 28, 29, 144. alamedensis, 144; plate showing, opp. 232. Index californicus, 30, 145; plate showing, opp. 2382. cholamensis, 145, 146; plate show- ing, opp. 234. oregonensis, 147, 148; plate show- ing, opp. 234. Hipparion, 288. Hipponoe californica, 56. depressa, 56. Hyaenarctos, 250, 347. gregoryi, 340, 342; plate showing, 343; characters of, 342; com- parisons of teeth, 345; with teeth of Hyaenarctos from Red Crag, 347; of H. punjabiensis, 346; of H. Sivalensis, 345; of Indaretos oregonensis, 346; of Indaretus salmontanus, 346; description of, 342; first molar of, 344; small carnassial of, 344. palaeindictus, 345. punjabiensis, 345, 346. sivalensis, 282, 345. Hyatt, A., 241. Hypertragulus, Tecuja Cafion form (lower jaw) compared with John Day species, 269; plate showing, 270. ordinatus, 270. Hypolagus edensis, 348; characters of, 348; compared with H. vetus, 348; plate showing, 348. vetus, 348. Ilingiceros?, sp., 382. Indarctos oregonensis, 341, 346. Indarctus salmontanus, 346. India, 32, 248. Indian Pliocene, 363. Isostatie flow, 434. Jacalitos formaton, 21. Jordan, D. S., 245. Jurassic flora, 251. Jurassic (?) system, 6. Kansas, 287. Kellogg, Miss L., 248. Kellogg, R., 250. Kew, W. S. W., 23, 245. Knowlton, F. H., 251. Laccolithie structure, basalt, 7. Laganum, 33. Lagomorpha, 348. Lawson, A. C., 2, 431. Leda, sp., 10. Leidy, J., 246. Lepus, 293. Lesquereux, L., 250. Lick Observatory, migration of, 471; rate of increase of latitude of, 439; values for the latitude of, 438. Linthis (?) californica, 148. Little Pine fault, 17, 18. [437] Little Pine Mountain, 4, 17. Loma Alta Mountain, 4. Loma Prieta, geodetic station, 463. Louderback, G. D., 338. Lower California, 27. Lower Harrison, 270. Lower Miocene, 31. Lower Rosebud, 270. Lower 'Titanotherium beds, 270. Lytle, J. W., 426. Macrocallista conradiana, 10. Manix fauna, 248. Marsh, O. C., 246. Martin, B., 243, 244. Martinez fauna, 243. Mascall Miocene, 249. Meek, IF. B., 240. Megalonyx, 349. sp. 293, 294, 320, 350; compared with Megalonyx from Hawver cave, 294; with Megalonyx from Potter Creek cave, 320, 350; with Megalonyx jeffersoni, 320, with White Bluff specimen, 320; with Mylodon from Rancho La Brea, 293; descrip- tion of, 350; plates showing, 294, 320. wheatleyi, 321. Meganos (fossils), 9. Megatylopus, 363. Megatylops gigas, 363. Mellita, 30, 137. longifissa, 34, 137; plate showing, 228. Mendenhall, W. C., quoted on uplift of San Bernardino Mountains, 314. Meretrix hornii, 10. Merriam, J. C., 26, 237. Merriamaster perrini, 129. Merycodus? sp., 382. Merycodus? or Ilingoceros?, 340. Mesozoic flora, 251. Mesozoic reptile, 246. Miller, L. H., 247, 248. Miocene, 13, 31, 243; Lower, 31; Maseall, 249; at Phillip’s Ranch, 248. Mission Pine, 4. Mobility of the Coast Ranges of Cali- fornia, The, 431. Mocho-Diablo base, 453; uncertainty as to immobility of, 472. Modiolus ornatus, 10. Mohave Desert, 248. Mono Creek, 4. Monterey group, 13, 17, and cherts of the, 19. Monterey series, 268; not character- ized by homogeneity of vertebrate faunas, 274. Mount Toro, geodetic station, 466. 21; shales Index Mounted Skeleton of Mylodon Har- lani, 425. Mylodon, 425. harlani, characters of, 426; mounted skeleton, 425; plate showing, opp. 430. robustus, 425. Nassa californica, 15. Nebraska, 287. Neocene, 31; fauna of the, 29. Nevada, 247. Nomland, J. O., 244, 245. Nothrotherium, 349. Nothrotherium? or Pronothrotherium?, sp., 349; description of, 349; plate showing, 349. Nyctilochus whitneyi, 10. Oakland conglomerate, 8. Odocoileus, 283. (?) two or more species, compared with O. hemionus and O. colum- biana, 296; plates showing, 296, 297, 298, 299. columbiana, 296, hemionus, 296. Oligocene, 12, 31. Olympic Peninsula, 244. Orcutt, W. W., 248. Ostrea, sp., 14. Ostrea, ef. idreaensis, 10. Outline of Progress in Palaeonto- logical Research on the Pacific Coast, 237. Pacific Coast genera, phylogenetic tree for, 38. Pacific Coast, geologic time scale for the, 26. Pacific Coast Province, 244. Pack, Robert, 26. Packard, E. L., 243. Palaeobotanical investigations, 250. Palaeontological research on_ the Pacifie Coast, outline of progress bhaeBit hr Palaeontology, invertebrate, 239; ver- tebrate, 245. Panama, 34. Paso Robles formation, 16. Peceary, 283. Pecten magnolia, 13, 14, 78. Pelecypods, mactrine of the West Coast, 243. Periarchus, 33. Perris-peneplain, 279. Persia, 248. Phillip’s Ranch Miocene, 248. Phylogenetic series, 35; - principal criteria used in, 35. Phylogeny of the Pacific Coast echi- noid families, statement of the, 37. Pinniped remains, 250. Pinole Tuff-Orinda, 287. [438] Platygonus, 288. bicalearatus, 355. compressus, 356. labiatus, 356. ?sp., 354; description of, 354; com- parisons of, 365; plate show- ing, 355. texanus, 356. Pleistocene fauna, Rancho La Brea, 247; of eastern Oregon, Fossil Lake, 247; Bautista, description of, 293. Pleistocene rodents, 248. Pliauchenia, 288. gigas, 361, 366. merriami, 288, 357, 358; characters of, 358; compared with Came- lops hesternus, 362; description of, 358; limb elements of, 364; lower jaw, 360; upper jaw, 360; plates showing, 357, 359, 365, 377, 418. ?sp., 321; plate showing, 321. sp. A, 266; plates showing, 365, 377, opp. 418. spatula, 361. Pliauchenia-like species, plate show- ing, opp. 420. Pliocene, 15, 32; fauna, 244; Eden, 339; Etchegoin, 244; San Timo- teo, 320; Fernando, near New- hall, 244; Indian, 363; Rattle- snake, 249. Pliohippus, 283; limb elements of, 403; plate showing, 403; upper milk teeth referred to, 391; plate showing, 392. cumminsii, 288, 328. edensis, n.sp., 388; characters of, 388; description of teeth, 388; lower cheek teeth near, 400; medium-sized lower teeth near, 396; plates showing, 387, 397, 398, 400. subform A, 388; characters of, 389; compared with P. spec- tans, 389; description of teeth, 389; plate showing, 389. subform B, 391, 398; characters of, 391; description of teth, 391; large lower cheek teeth near, 398; plates showing, 390, 399. fairbanksi, 288. francescana, 322; characters of, 323; dentition of, 326; com- pared with dentition of Equus bautistensis, 327; of P. fran- cescana minor, 329; of P. pro- versus, 328; of P. simplicidens, 328; description of material, 323; plates showing, opp. 325. 326, and 416. Index minor, 327, 330; characters of, 330; dentition compared with den- tition of P. eumminsii, 332; of P. proversus, 332; of P. sim- plicidens, 332; description of material, 330; plates showing, 329, 330, 331, 322. indet., lower cheek teeth of, 401; plate showing, 401. interpolatus, 333. mirabilis, 288. osborni, 332; plate showing, 393. n.sp., 383; characters of, 383; description of teeth, 384; lower cheek teeth tentatively referred to, 393; plate show- ing, 384. subform A, 385; description of teeth, 386; lower teeth tenta- tively referred to, 394; plates showing, 384, 385, 395. proversus, 289, 309, 328. simplicidens, 288, 328. spectans, 288, 389. ? Pliohippus, lower milk teeth of, 402; plate showing, 402. Point Arena group of geodetic sta- tions, 456. Point Pinos, geodetic station, 468. Potrero Creek deposits, 338. Potter Creek cave, 247. Proboscidea, 288. Procameline, indet. sp., 340. Procamelus, 288; plates showing, 376, 377. edensis edensis, 367; characters (generic) of, 367; description of, 370; description of referred specimen, 370; plates showing, 368 and 369. raki, 367; characters of, 370; description of, 371; plates - showing, 368 and 369. gracilis, 374. indet. sp. or subsp., 373; descrip- tion of, 373; limb elements of, 375; plates showing, 373 and 374. robustus, 366. (?) sp. A, 372; characters of, 372; plate showing, 372. Procamelus-like species, 367; plates showing, 365 and opp. 420. Promerycocherus beds, 270. Pronothrotherium, 349. Prosthennops, 288. crassigenis, 352. edensis, 350; compared. with P. crassigenis, 3852; with Pros- thennops-like specimen from Thousand Creek, Nevada, 352; description of, 351; generic and specific characters, 351; lower jaw referred material, 353; lower premolar compared with lower premolar of Platy- gonus, 353; of Mylohyus from the Conard fissure, 353; of Presthennops crassigenis, 354; with material from Merychip- pus Zone of Coalinga, 354; from Rattlesnake formation, Oregon, 354; upper jaw re- ferred material, 352; plate showing, 357. Protapirus robustus, 313. Protohippus, 332. Psammobia, ef. hornii, 10. Puget Sound, 29. Pulgas West Base, geodetic station, 465. Quaternary system, 16. Rabbit, 283. Radiolarian cherts, 7. Rancho La Brea, 248; Pleistocene fauna, 247. Rattlesnake Pliocene deposits, 249, 287. Red Hill, geodetic station, 462. Redrock fault, 17. Reid, H. F., 432. Rémond, 26. Reptiles, marine Triassic, 247. Republican River, fauna of the, 287. Rhinoceros, teeth of, 271. hesperius, 272. Rhinocerotidae, 288. Rhynchopygus, 29, 30, 138. pacificus, 141. Ricardo lower Pliocene, 248, 287. Rocky Mound, geodetic station, 461. Rodents, Pleistocene, 248. Rosebud, Lower, 270. Ross Mountain, geodetic station, 436; interpretation of data, 449; movements of, 447, 454. Rothpletz, A., 433, 459, 469, 472. Salinas shale, 13, 14. Samwel cave, 247. San Andreas fault, 443 passim. San Andreas rift, 433; longitudinal and transverse strain in region of, 443. Sandstone, bluff of the Tejon, 19. Sandstone, Vaqueros, 13. San Francisco Bay, 31. San Jacinto Quadrangle, 281; map showing, 281. San Joaquin Valley, map of, 268. San Mareos Pass, 21. San Rafael Mountains, 4, 21. Santa Ana Mountains of Southern California, 30. Santa Cruz, geodetic station, 468. Santa Cruz Creek, 4. Index Santa Ynez anticline, 21; fault, 11, 16, 17, 20. Santa Ynez Mountains, 4, 20, 21. Santa Ynez Peak, 4. Santa Ynez River, 4, 16, 18. Santa Ynez River District, geology of a part of the plate showing struc- ture sections, opp. 16. San Timoteo Badlands, 284; Tertiary deposits of the, 314. San Timoteo Cafion, 283. San Timoteo deposit, occurrence of fossils in, 319; description of Plhocene fauna, 320. Schilling, K. H., 274. Schizaster, 28, 148; ef. diabloensis, 10. californicus, 148; plate showing, opp. 234. cordiformis, 149; plate showing, opp. 236. diabloensis, 31, 150; plate showing, opp. 234. lecontei, 31, 150, 151; plate show- ing, opp. 234. martinezensis, 150, showing, opp. 236. stalderi, 154; plate showing, opp. 153; plate 236. Seiurid, 272; plate showing, 273; com- pared with Citellus, 273. Scutaster, 29, 135. andersoni, 31, 135; plate showing, opp. 204. Seutella, 28, 39; phylogenetic tree for genus, 40, cf. merriami, 14. aberti, 33. andersoni, 39, 62; plate showing, opp. 176. ashleyi, 115. plancoensis, 29, 39, 64; plate show- ing, opp. 174. breweriana, 91. coosensis, 39, 65; plate showing, opp. 168. (Echinarachnius ) oregonensis, 132. excentrica, 121. fairbanksi, 39; plate showing, opp. 174. santanensis, 68; plate showing, opp. 174. gabbi, 39, 69; plates showing, opp. 176 and 178. tenuis, 40, 67, 71; plate showing, opp. 178. gibbsii, 122. interlineata, 131, 134. merriami, 31, 39, 72; plate show- ing, opp. 176. mirabilis, 37. newcombei, 29, 73; plate showing, opp. 168. excentricus, 121. norrisi, 31, 75; plate showing, opp. 170. pabloensis, 106. parma, 33, 34. perrini, 129. ?striatula, 121. tejonensis, 39, 76; plate showing, opp. 176. vaquerosensis, 77; plates showing, opp. 168 and 170. Seutellidae, 29. Sedimentary strata, 7. Sespe formation, 9, 12, 21, 275. Shale, Salinas, 13, 14. Shales and cherts of the Monterey group, 19. Shasta rocks, 8. Sierra Morena, geodetic station, 465. Silica-carbonate rock, 7. Sinclair, W. J., 247. Sismondia, 61; (?) 30. arnoldi, 61; plate showing, opp. 160. coalingaensis, 62, 117; plate show- ing, opp. 160. merriami, 72. Slicing shear, 440. Smilodon?, sp., 341; plate showing, 340. Smith, J. P., 241. Snake Creek, 287. Soboban area, 289. Sonoma, geodetic station, 447; inter- pretation of data, 449; move- ments of, 447. Sooke beds, 29. Spatangidae, 29, 143. Spatangoidea, 143. Spatangus, 29, 155. pachecoensis, 31, 155; plate show- ing, opp. 236. .Sphenophalos, 381. [440] Spiroglyphus, sp., 14. Stanton, T. W., 241. State (California) Earthquake Inves- tigation Commission, cited, 432. Sternberg, C. H., 246. Stock, C., 249, 267, 425. Strain, longitudinal, 471; longitudinal on a lowly inclined fault, 470; transverse, 471; hypothesis of persistent northerly, 472. Strain creep, rate of, 444; rate of northerly, 436. Strongylocentrotidae, 57. Strongylocentrotus, 28, 30, 57. drdbachiensis, 32. franciscanus, 57; opp. 160. purpuratus, 58. ; Suberustal current, hypothesis of, 443. Suberustal flow, hypothesis of, 435. plate showing, Index Summerland, 10. Sureula io, 10. Tamalpais, geodetic station, 4386; in- terpretation of data, 449; move- ments of, 445. Tapir, 283. Tapirus, 311. haysii, 311, 314. ealifornicus, 311, 313. merriami, 293, 311; characters of, 311; comparison with T. haysii from Port Kennedy Cave, 311; with T. haysii californicus from the Auriferous Gravels, 311; deseription of, 311; plate show- ing portion of mandible, 312. Taylor, W. P., 249. Tecuja Canon, 269. Tecuja fauna, age and relationships of, 273. Tehuichila, 341. Tejon formation, 9; bluff standstone of the, 19. : Tellina remondii, 10. Terebratalia kennedyi, 14; (?), 140. Terrace deposits, 16. Tertiary and Cretaceous floras, 251. Tertiary deposits of the San Timoteo Badlands, 314; extent of, 314; composition of, 314. Tertiary faunas, 242. Tertiary flora of John Day region, 251. Tertiary mammalan assemblage, 268. Tertiary series west of the Sierra Range, 249. Tertiary system, 9. Tesla district of Middle California, 30. Testudinata, 334; plate showing, 334. Tetrocidaris perplexa, 54. Texas, 287, 289. Thalattosauria, 247. Thousand Creek, 287. Tiger, saber tooth, 283. Titanotherium, Lower, 270. Tomales Bay, geodetic station, move- ments of, 450; maximum dis- placement at fault trace, 453. Topatopa formation, 9. Tortoise, 283. Toxocidaris franciseana, 57. globosa, 57. Triassic Ichthyosauria, 247. Triassic reptiles, marine, 247, Trilophodon, 283. shepardi, 403; plate showing, 403. (Tetrabelodon) shepardi edensis, 405; characters of, 405; de- scription of, 407; teeth com- pared with teeth of T. flori- danus, 409; of Tetrabelodon shepardi, 409; plate showing, 406, opp. 424. Tripneustes, 30, 56. ealifornicus, 56. (Hipponoé) californicus, 56; plate showing, opp. 158. Tucker, T. H., 438. Turris suturalis, (?), 10. Turritella andersoni, 10, 151. inezana, 13. ocovana, 13, 14. sp., 10. uvasana, 10. Turritella inezana fauna, 275. ocoyana fauna, 275. Twitchell, 26. Ukiah, geodetic station, 436; migra- tion of, 471. Ungulates, 249. Ursidae, 341. Ursus, 341. Vaqueros sandstone, 12, 13. Venericardia planicosta hornii, 10. Wagener, C. M., 274. Ward, L. F., 251. Weaver, C. E., 26, 245. Western Plains, region, 287. White, C. A., 241. Whitney, J. D., 239. Wood, H. O., 434, 459. Wortman, J. L., 246. Wyman, L. E., 426. ERRATA Page 438, first item in fourth column under ‘‘ Latitude.’’? For 37° 20’ 2687 read 37° 20’ 25787. Lh 1 a all cou i i : 7 * 1 7 = oo” F an - * 1 ae ‘ + : - ‘ a 7 an t . _ oT : i - 1 f. i 7 os 7 ee ' : Fs : ve . : < + 7 a : ‘Ee 4 7 7 “aa rae a - : . fe at ie i 5 ' ¥ 7 * ie ‘ fakery a) ! " —_- rs 2 Nv a4, . The Pliocene of Middle and Northern California, by Bruce Martin » Mesozoic and Cenozoic Mactrinae of the Pacific Coast of North America, by Earl. UNIVERSITY OF, CALIFORNIA PUBLICATIONS— (Continued) . A Review of the Species Pavo californicus, by Loye Holmes. Miller .............-2--2::----- . The Owl Remains from Rancho La Brea, by Loye Holmes Miller ............2-.2--222::2-- - Two Vulturid Raptors from the Pleistocene of Rancho La Brea, by Loye Holmes ELM Cie ecraa pap ecco ree a On Oe i PE eee a VA wa MEE SEPT ee ep OER . Notes on Capromeryx Material from the Pleistocene of Rancho La Brea, by Asa C. OU DEALT Gah les (AS GRISEA gt AR. at ect mE Os SP RAC NT NO . A Study of the Skull dnd Dentition of Bison antiquus Leidy, with Special Reference to Material from the Pacific Coast, by Asa C. Chandler -.......0..2..20--2.20ctieeee eine . Faunal Studies in the Cretaceous of the Santa Ana Mountains of Southern Cale Sv 1 Aye oh oii Bld) oY) aE TCC eo Rf EE hos BORO nardl_nor ei A eee oe 7 . Tertiary Vertebrate Fauna from the Cedar Mountain Region of Western Nevada, means Om Wierriamerrias monet Ten ee eS ee a . Fauna from the Lower Pliocene at Jacalitos Creek and Waltham Cafion, Fresno Crime Oalitanniascby: Joreen -O. Nomlamd! hi S22 ie kee ee Brrr Lata rer se ee as We eer Nal UO ee ce 1 eT ee ge . The Stratigraphy and Fauna of the Tejon Eocene of California, by Roy H. Dickerson . Relationship of Equus to Pliohippus Suggested by Characters of a New Species from the Pliocene of California, by John C.. Merriam .2..)...2-2.22.-scecpeseeeeceeneceeeeeeeneeee VOLUME 10 . The Correlation of the Pre-Cambrian Rocks of the Region of the Great Lakes, by Sm STrESLUM Oa ny S OTM ose ee ee Lg cod ea oa ee . A New Mustelid from the Thousand Creek Pliocene of Nevada, by Emerson M. Sanne TAC IN RLS tie Leas ees a Me Ti Ie pare i eae ae a ae ee i . The Occurrence of Ore on the Limestone Side of Garnet Zones, by Joseph B “Ta hilelOS7 cette Bate ee cf ae Se ne ee ORO aM it eS ae Re Ee ae Se . Fauna of the Fernando of Los Angeles, by Clarence L. Moody ...........2..2222.2:4-2200--- . Notes on the Marine Triassic Reptile Fauna of Spitzbergen, by Carl Wimaw............ . New Mammalian Faunas from Miocene Sediments near Tehachapi Pass in the Mouniernesiorra, Nevada, by John P. Buwalday 1... 0b... ce ce eee eens . An American Pliocene Bear, by John C. Merriam, Chester Stock, and Clarence L. SLL WE CIF et ca SR Be ei i a Sal en SN eM epee Maer ee PE eR . Mammalian Remains from the Chanae Formation of the Tejon Hills, California, by John C. Merriam. . Mammalian Remains from a Late Tertiary Formation at Ironside, Oregon, by John C. Merriam. IMoparerand 9 imsOme; COVER)... 22-522... soca ER As MEE Se ee ete ee eee . Recent Studies on the Skull and Dentition of Nothrotherium from Rancho La Brea, "CUSTER ES HOY hg Se SS a eee aN eter EN ee a eRe . Further Observations on the Skull Structure of Mylodont Sloths from Rancho La Te He, Vag CUNGISTIGEAITS ELOY CI ie ve coal cor RS MOPS ORES see RP PN . Systematic Position of Several American Tertiary Lagomorphs, by Lee Raymond Tle: coccecinads 5 ROS IR TR I SS PS Se RN a Ne Ne Re Ee Sao ARE Oe er Reco eS . New Fossil Corals from the Pacific Coast, by Jorgen O. Nomland ..............-2..2.....2------+ . The Etchegoin Pliocene of Middle California, by Jorgen O. Nomland ......................-. . Age of Strata Referred to the Ellensburg Formation in_the White Bluffs of the Columbia River, by John C. Merriam and John P. Buwalda ..............0.20.22..2s21eeteeo . Structure of the Pes in Mylodon harlani, by Chester Stock -.....0.220.2..2.-1.2.:-1:cteeeeeeeee . An Extinct Toad from Rancho La Brea, by Charles Lewis Camp ...............--.-.-2.-221----- . Fauna of the Santa Margarita Beds in the North Coalinga 1 of California, by Tegra OM Deora kaa 6 Ua A as a ae 2 eC et . Minerals Associated with the Crystalline Limestone at distr, Riverside County, SPANO TIA Og PA UIE SH ABI DIGUG) tect sek Ot cacla a eape cu varannenonarevevtvencnenrnasceboavoe tnaepobenbecsedul . The Geology and Ore Deposits of the Leona Rhyolite, by Clifton W. Clark ............-..- . The Breccias of the Mariposa Formation in the Vicinity of Colfax, California, by CoM ai Spa PS, op, SINUIO YOY Fy, Ba ca Le ne a . Relationships of Pliocene Mammalian Faunas from the Pacific Coast and Great Basin irovances of North America, by John C. Merriam ...0.....2.:.-s0ecc--s.-ccccenecdeccenenecesoeneencud UNIV ERSITY OF cal FORN TA 23. Anticlines near r Sunshine, Park County, Wyoming, by 10% PORTO: sic2 ee venasbnn iA. ates antes Dee tee eee aes See 24, The Pleistocene Fauna of Hawver Cave, by Chester Stock ...... 25. Evidence of Mammalian ae Relating to the fA. of Tee John C, eeu C. Merriam. 28. New Puma-like Cat from Rancho La Brea, by J ohn C. Merriam. : Nos: 26; 27,-and 287m ‘owe: cover -...2.. ee, eee apes: VOLUME 11 1. The Franciscan Sandstone, by EB. YS Daviau: ee : 2. The San Lorenzo Series of Middle California, a Stratigraphic and Palaeon ol Study of the San Lorenzo Oligocene Series of the General Region of Mount Diablo, California, by Bruce L. Clark =, The Radiolarian Cherts of the Franciscan Group, by HE. F, Davis .. rome 5. Tertiary Mammalian Faunas of the Mohave Desert, os John C. Merriam - . Index in press. \ VOLUME 12 wen a ee 25 . Geology of a Part of the Santa Ynez River District, Santa Barbara 3. An Outline of Progress in Palaeontological Research on the Pacific Coast, by G5 Merriam ro. ist gan eae enecn gedek sap tage ce heb eet cennse anon geen err 4, An Early Tertiary Vertebrate Fauna from the Southern Coast Ranges of Calitorn bys Chester Stole -:.33.i8 0 See ee Be ee _ 5. Extinet Vertebrate Faunas of the Badlands of Bautista Creek ana San Tim ‘ Canon, Southern California, by Childs Prick -2...0.-2.-22cs.--cccecsnccecndeenteresbeereneeepeneeee 6. A Mounted Skeleton of Mylodon harlani, by Chester Stock s....-...-..-----:c:secceeeeeeeeee 7. The Mobility of the Coast Ranges of California. An Exploitation of the Elastic Rebound Theory, by Andrew C. Dawson * .......5csc.cietl cess aeoe Ny ME Dig ets Uy a Gntiat AT ANG i er iy sll he ny Ae 1 ea MG OMY bi, (Lor \ aL np My ! lM aa) Pain, | Pa hs Cpe US nyt ioe r py | 1 On if : am , heh Oa a a vin \ ie : 7 fi. aay, aa fu a ne 7 bee 2 o as wa a4 ve ben ny ec! ad i Le Ww aig ne ps les We Ad AY ry i ei ia aye Ma: Se in atk sal aL}, » ii ih af a ; Le : dann i iy 1 a i - i 7 ey . a 1 : al , Lae he b ny ae) ie uy ‘ oy te poets hy 7 U | ‘ ms ini ‘y , Pe uli\d OR ae op aM Masel Ni & i : Lae mu aul a em a ; 1 er PTT Pps 2 My eee | dated | agian ||) |) ||. tbl NAagaar” YYSAT Ayaan nigral fice ereerrr rar ih {ft tae? Nada watig 14 wupyprrun Nu , a%ya pe i ee a, 00 eerie HP why an? a ae aa of Nee 8 ee ne pee rea agh* 2, 8 ? 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