PaleoBios, Volume 17, Numbers 2-4, Pages 28-49, September 13,1996 A review of the biostratigraphy of Pliocene and Pleistocene sediments in the Elsinore Fault Zone, Riverside County, California Alois F. Pajak III1, Eric Scott2, and Christopher J. Bell3 Quaternary Studies Program, P.O. Box 5644, Northern Arizona University, Flagstaff, Arizona 86011 Section of Earth Sciences, San Bernardino County Museum, Redlands, California 92374 Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, California 94720 ABSTRACT Three fossil-bearing sedimentary formations are known from the Elsinore Fault Zone within the Temecula basin. The Temecula Arkose, stratigraphically lowest of these formations, crops out primarily in the southeast- ern portion of the basin. An unnamed sandstone and conglomerate formation crops out near Murrieta and the Pauba Formation, the uppermost formation, unconformably overlies the Temecula Arkose and the unnamed sandstone formation in the center of the fault trough. A kaolin deposit within the unnamed sandstone has been correlated with the Bishop Ash (0.785 ± 0.002 Ma), but is not found in direct association with vertebrate faunas. Assessments of the age of these three units have been based primarily on the composition of the vertebrate faunas recovered from localities throughout the fault trough. Recent analyses of mammalian fossils recovered from the region permit more detailed biochronologic interpretations of these formations. Faunas from the Temecula Arkose are referred to the Blancan land mammal age, based upon the presence of Onychomys gidleyi, Calomys arizonae and Neotoma (Paraneotoma) sawrockensis low in the section and the co-occurrence of Tetrameryx and Nannippus higher in the section. The age of the unnamed sandstone formation ranges from the late Pliocene (Blancan) to the middle Pleistocene (Irvingtonian); an interpretation based upon the identification of three recognizable and apparently distinct faunal components within this unit These components are informally designated the Paraneotoma faunal unit (middle to late Blancan), the Mimomys faunal unit (latest Blancan), and the Microtus/Mammuthus faunal unit (early to middle Irvingtonian). The age of the Pauba Formation ranges from the middle Pleistocene (Irvingtonian) to the early late Pleistocene (latest Irvingtonian), based upon the superpositional relationship of this formation to the unnamed sandstone as well as the presence within the formation of Microtus and Mammuthus and the absence of Bison. Following the biochronologic interpretations of Lundelius et al. (1987), Repenning (1987) and Repenning et al. (1990, 1995), the Temecula Arkose ranges in age from possibly 6.0 Ma to ± 2.7 Ma; the unnamed sandstone dates from ± 3.5 Ma to ± 0.75 Ma; and the Pauba Formation falls within the range of < 0.6 Ma to > 0.12 Ma. In recent years, reevaluation of the taxonomic composition of several faunas has resulted in important changes in the interpretations of the age of the formations; a summary of the significant vertebrate fossil localities from the Elsinore Fault Zone and their contained mammalian faunas is provided in an effort to resolve a long history of confusion regarding specific taxonomic affinities and chronologic assessments of faunas from the region. INTRODUCTION The Temecula basin, located inland and ap- proximately 120 km southeast of Los Angeles in Riverside County, California (Figure 1), is the physi- ographic region bounded by the Perris block to the north, the Santa Rosa Plateau to the south-south- west, and the Oak Mountains to the southeast (Mann, 1955). The Pliocene and Pleistocene sedi- ments of this basin fill topographic lows formed by down-dropped blocks of crystalline basement rock within the boundaries of the Elsinore Fault Zone (Kennedy, 1977). These sediments have been heavily faulted by movement within the Elsinore Fault Zone and the associated complex of north- west-striking, discontinuous en echelon faults, re- sulting in complications in interpreting the deposi- tional history of the region (Golz et al., 1977; Kennedy, 1977). Sedimentary exposures in the Temecula basin were the subject of several geologic investigations over the past four decades. Due to lack of radio- metric dates in reliable stratigraphic context from In The Uses of Vertebrate Fossils in Biostratigraphic Correlation (C. J. Bell and S. S. Sumida, eds.). PaleoBios v. 17(2-4) Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 29 this area, determinations of geologic age were based primarily on biostratigraphic analyses. Early efforts to determine the age of the formations were made from biostratigraphic interpretations based on rela- tively meager collections of vertebrate fossils (Mann, 1955; Golz et al., 1977; Kennedy, 1977; Repenning, 1987). Paleontologic salvage activities over the last six years yielded numerous fossil specimens from new localities that enabled workers to address the age and depositional sequence of the region in greater detail (Reynolds and Reynolds, 1990a, 1990b; Reynolds et al., 1990,1991; Bell, 1993; Pajak, 1993; Scott and Cox, 1993; Figure 2; see Appendix A). These authors assigned relative ages to three formations based on taxa taken to be indicative of the North American Land Mammal Ages. Since information has been presented piecemeal and new unpublished data updates previous work, a synthe- sis of this work necessitates reevaluation and en- hancement of these interpretations. PREVIOUS WORK Preliminary geologic investigations resulted in recognition of two sedimentary formations in the Elsinore Fault Zone from the Murrieta and Temecula regions (Mann, 1955). The lowest of these formations, the Temecula Arkose, consists in the type area near Pechanga primarily of pale greenish- yellow, well-indurated, medium- to coarse-grained sandstone beds averaging a meter in thickness (Mann, 1955). Deposited unconformably above the Temecula Arkose, the Pauba Formation was said to consist of "250 feet (70 m) of hardpan-lithified fanglomerates, yellow and red arkoses, brown silts, and diatomite" (Mann, 1955, p. 3). The original designation of the age of the Temecula Arkose as "post-late Pliocene" was based upon fossil vertebrates identified by R. A. Stirton and D. E. Savage (Mann, 1955). Taxa originally reported from this formation include Eqims sp., Antilocapra sp. or Tetrameryx sp., lOdocoileus sp. and IBison sp., as well as an indeterminate probos- cidean, a large cat and a coyote-sized carnivore (Mann, 1955). Subsequently, exposures of the Temecula Arkose near Radec (Locality NHMLAC 1657; Fig- ure 1) were assigned to the later Blancan land mam- mal age based upon the co-occurrence of Equus sp., Odocoileus sp., Tetrameryx sp. and large and small species of Hypolagus (cf. H. regalis and cf. H. limnetus, respectively) (Golz et al., 1977). This bio- chronologic age assessment was further substanti- ated by the occurrence of Nannippus sp. from addi- tional exposures of the Temecula Arkose which were considered to be essentially stratigraphically equivalent to the Radec locality (Golz et al., 1977). The "post-Blancan" age suggested by Mann (1955), based primarily upon the presence of IBison sp. in the fauna, could not be confirmed since the original specimens referred to Bison sp. could not be located to verify identification (Golz et al., 1977). Biochronologically, the Temecula Arkose was de- termined to fall between ±2.7 Ma and 2.2 Ma, based upon the first appearance of Tetrameryx in the fossil record and the later extinction of Nannippus (Lind- say et al., 1975). Repenning (1987) proposed a substantially earlier date of approximately 4.5 Ma for exposures of the Temecula Arkose near Radec, on the basis of the occurrence of Neotoma (Paraneotoma) sawrockensis near the base of the section (cited by Reynolds and Reynolds, 1993; Figures 3 and 4). Similarly, Reynolds and Reynolds (1993) docu- mented the presence of an extensive microfauna from exposures of the Temecula Arkose near Radec at localities SBCM 05.002.016 and NHMLAC 1657 (Figures 1 and 4; Appendix A). Reynolds and Reynolds (1993) reported a biochronologic date of 4.5 Ma for this fauna and essentially equated this locality with the Radec locality reported by Repenning {1987) and Golz et al. (1977) (Appendix A). Since then, however, R.E. Reynolds (pers. com. to E. Scott, 1996) has indicated that these localities are not the same and that further work will show the differences. In essence, the lower Temecula Arkose was considered to correspond to the Blancan I microtine rodent subdivision of Repenning (1987) (Reynolds and Reynolds, 1993). This assessment was based upon the presence of Onychomys gidleyi, Calomys arizonae and a small form of Neotoma {Paraneotoma) qimdriplicatus, as well as a large and a small species of Hypolagus (H. vetus and H. edensis, respectively, contra the species reported by Golz et al., [1977]; Reynolds and Reynolds, 1993.) Neotoma (Paraneotoma) sawrockensis was not repre- sented in this fauna. Prothomomys warrensis, Cupidinimus sp. cf. C. bidahochiensis, Copemys vasquezi and Peromyscus valensis (taxa typically con- sidered to be Hemphillian) were present in the fauna, but were interpreted to be "holdover" taxa demonstrating significant range extensions into the Blancan rather than indicators of a Hemphillian faunal component in the Temecula Arkose (Reynolds and Reynolds, 1993). Because of an un- derlying lack of stratigraphic context in early stud- ies, different ages were proposed for the Temecula Figure 1. Index and geologic map of the Temecula basin (after Mann, 1955; Kennedy, 1977). The Radec locality of Repenning (1987) and localities NHMLAC 1657 and SBCM 05.002.016 are in the vicinity of Radec. I Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 31 Arkose; later Blancan (Golz et al., 1977) and earliest to middle Blancan (Reynolds and Reynolds, 1993). The northern exposures of the Temecula Arkose near Murrieta, as mapped by Mann (1955), were assigned to a third sedimentary unit infor- mally designated as an unnamed sandstone and conglomerate formation ("the unnamed sandstone") (Kennedy, 1977; Figure 1). This unit is unconformably overlain by the Pauba Formation and may in turn unconformably overlie the Temecula Arkose (Kennedy, 1977). The unnamed sandstone consists in part of pale greenish-yellow, medium-grained, friable, caliche-rich sandstones, lithologically similar to the Temecula Arkose, but differing in having a northern-northeastern source area (Kennedy, 1977). A 2-3 m thick kaolin horizon interstratified with exposures of the unnamed sandstone was re- ported approximately 3 km northwest of Murrieta at Chaney Hill (Figure 2). The ash from the Chaney Hill deposit was positively chemically correlated with the widespread Bishop Ash (Merriam and Bischoff, 1975; Kennedy, 1977; Sarna-Wojcicki et al., 1984), the current date of which is 0.785 ± 0.002 Ma (A. M. Sarna-Wojicicki, pers. com., 1996). This date provides a "ballpark" radiometric age for a portion of the unnamed sandstone, but vertebrate fossils are not known from the exposure that includes posi- tively identified Bishop Ash. Biostratigraphic analyses of vertebrate fossils from the unnamed sandstone indicate that an ear- lier, Pliocene Epoch component is present in addi- tion to the early Pleistocene sediments. Recent in- vestigations based upon fossils derived from pale- ontologic salvage (Reynolds and Reynolds, 1990a, 1990b; Reynolds et al, 1990, 1991; Bell, 1993; Scott and Cox, 1993) suggested the presence of at least two apparently discrete faunal components to the fossil vertebrate assemblage from the unnamed sandstone in the vicinity of Murrieta. The older component of the fauna was determined to be late Blancan (= latest Pliocene/earliest Pleistocene) in age, based upon the presence of Hypolagus sp., Prodipodomys sp., Mimomys (Ophiomys) parvus, Paraneotoma fossilis and Sigmodon minor (Reynolds et al., 1991; Scott and Cox, 1993). The younger faunal component included Pleistocene indicators Microtus sp. and Mammuthus sp., and was deter- mined to be Irvingtonian (= early to middle Pleis- tocene) in age (Scott and Cox, 1993). The Blancan and Irvingtonian faunas were thought to be in fault contact with one another (Reynolds and Reynolds, 1990a; Reynolds et al., 1991; Scott and Cox, 1993), since no transitional stage between the faunas was in evidence (Reynolds et al., 1991). Our consider- ation of these studies, combined with new informa- tion, reveals that a third faunal component is ap- parent in the unnamed sandstone and that there is also overlap between faunas indicating that a more complete biostratigraphic picture can be drawn. Mann (1955) and Kennedy (1977) described the Pauba Formation, which unconformably over- lies both the Temecula Arkose and unnamed sand- stone in the center of the basin (Figure 1), as a succession of approximately 75 m of either light brown, moderately well-indurated crossbedded channeled sandstones and siltstones or grayish brown, well indurated, poorly sorted f anglomerates and mudstones. The age of the Pauba Formation was based on both superposition to the unnamed Figure 2. Locality map for the unnamed sandstone (numbers 1 through 12) and Pauba Formation (number 13) localities (modified from USGS 7.5 Minute Murrieta Quadrangle and information provided by the Regional Paleontologic Locality Inventory, SBCM). 1) SBCM 05.006.084, 2) SBCM 05.006.083, 3) SBCM 05.006.089, 4) SBCM 05.006.090, 5) SBCM 05.006.155, 6) SBCM 05.006.159, 7) SBCM 05.006.397 8) SBCM 05.006.151 9) USGS vertebrate locality M1476 10) SBCM 05.006.301 11) SBCM 05.006.303 12) SBCM 05.006.305,13) SBCM 05.006.378. Page 32 Biostratigraphy of the Elsinore Fault Zone Pajak et al. sandstone and biochronologic interpretations. Mann (1955, p. 14) interpreted the age of the forma- tion to be Pleistocene on the basis of vertebrate fossil material, including a tapir and several horse teeth which he considered to be "modern in every respect and... much less indurated than horse teeth found in the Temecula Arkose." Debate continues as to the age of the Pauba Formation. Vertebrate fossils reported from the Pauba Formation include remains of Paramylodon harlani, Lepus sp., Sylvilagus sp., Sorex sp., Ammospermophilus sp., Dipodomys sp., Thomomys bottae, Peromyscus sp., Neotoma sp., Microtus californicus, Equus sp., Odocoileus sp., lAntilocapra sp., Hemiauchenia sp., Camelops sp., Mammut sp., and Mammuthus sp. cf. M. imperator (Reynolds and Reynolds, 1990b; Reynolds et al., 1991; Jefferson, 1989, 1991; McDonald, 1993). Reynolds et al. (1991) proposed a middle Pleis- tocene age (latest Irvingtonian to middle Rancholabrean) for the Pauba Formation on the basis of the occurrence of Microtus californicus and Mammuthus sp. cf. M. imperator. Arguments for a Rancholabrean age for the Pauba Formation are based on the report of Bison from the Pauba Forma- tion (Jefferson, 1991 on the basis of a mitigation report), the size analysis of Paramylodon harlani (McDonald, 1993) and radiocarbon dates of a peat layer (M. Morgan, pers. com., 1994), the strati- graphic position of which is not reliably established. In light of new evidence, discussed below, an Irvingtonian age seems more likely than the more problematic Rancholabrean age assessments. METHODS Recent biostratigraphic investigations of the Temecula basin were based primarily upon collec- tions of the San Bernardino County Museum, Redlands, California (SBCM) (Reynolds and Reynolds, 1990a, 1990b, 1993; Reynolds et al., 1990, 1991; Bell, 1993; Pajak, 1993; Scott and Cox, 1993). The majority of the fossils discussed in the reports are the product of paleontologic salvage activities conducted by the Paleontologic Resource Assess- ment Program of the SBCM, as well as private miti- gation agencies. Under federal, state, and local guidelines, vertebrate paleontologists are con- tracted by developers to mitigate adverse impacts to significant nonrenewable paleontologic resources present in areas targeted for excavation and devel- opment. With the cooperation of these developers, exposed fossils and fossil-bearing sediments are sal- vaged during excavation activities. The recovered material is prepared to a point of identification and permanent preservation and then curated into the collections of the SBCM. Although the fossils are important, an emphasis on collecting geologic in- formation is a relatively recent development (Pajak, 1991; Fay and Thiessen, 1991). The present study synthesizes previously published biostratigraphic analyses and interpreta- tions based upon fossils from the Temecula Arkose, the unnamed sandstone and the Pauba Formation. Unpublished mitigation reports and locality data from the Regional Paleontologic Locality Inventory of the SBCM augment the published material. The number of identified specimens (NISP) is the total of the number of recovered specimens that were identified to at least the generic level. Biochronologic interpretations employed herein are based primarily upon chronologies set forth by Lundelius et al. (1987) and Repenning (1987), as modified by subsequent interpretations (Repenning et al., 1990,1995; Repenning, 1992). The term "land mammal age" is used here to refer to the mammal ages of the contiguous United States, par- ticularly of the western United States faunal region (Fejfar and Repenning, 1992; Repenning et al., 1995). The Blancan land mammal age is here consid- ered to begin at 4.8 Ma with the appearance of Mimomys in the North American fossil record; the Irvingtonian is determined to commence at 1.6 Ma (in the western United States faunal region; see Repenning et al., 1995) with the appearance of Phenacomys and Microtus and the subsequent ap- pearance of Mammuthus; and the Rancholabrean mammal age is determined to extend from approxi- mately 0.12 - 0.13 Ma (earliest appearance of Bison; see Repenning et al., 1990) to + 0.01 Ma (Figure 3). Supplementary biochronologic data for individual taxa, as advanced by Kurten and Anderson (1980), Savage and Russell (1983) and Lindsay and Butler (1987), are also utilized where appropriate (Figure 3). Except where noted, previous taxonomic as- signments were updated to conform to the tax- onomy set forth by Carroll (1988) and Nowak (1991). Some specimens were re-examined to con- firm or reject problematic published identifications. However, for the purposes of this study, the major- ity of the identifications are considered correct until further study. A partial catalogue of localities in the Temecula basin is provided (Appendix A); included in this list, to the best of our knowledge, are refer- ences for the taxonomic identifications for each lo- cality. It is important to note that many of the fossils discussed herein would have been destroyed with- out the proper paleontologic mitigation guidelines Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 33 Taxa Onychomys gidleyi w Calomys arizonae 1>2 Neotoma (P.) U sawrockensis Neotoma (P.) l<2 quadriplicate Nannipus sp. Paraneotoma fossilis Ma 4 . 3 2 1 0.5 0.01 i i ¦ i i Epoch PLIOCENE PLEISTOCENE K LMA B 1 a n c a n / Irvingtonian Rib | **r 2,4 7,8 10 Megalonyx leptostomus Hypolagus sp. Prodipodomys sp. Mimomys (0.) parvus2'4 Sigmodon minor 4'6 Platygonus bicalcaratus Tetrameryx sp.3'5 Megalonyx wheatleyi 7'8'u 7.8 10 Paramylodon harlani *' Microtus sp. 2*12 Arctodus simus ' Mammuthus sp. Smilodon fa talis 13 10 3,10 10 Tapirus californicus Bison sp.3'10 ^ Figure 3. Taxon range chart for the recovered potentially biostratigraphically significant vertebrates from the Temecula basin. Numbers following taxon names correspond to references from which temporal ranges were taken: 1) Reynolds and Reynolds, 1993; 2) Repenning, 1987; 3) Lundelius et al., 1987; 4) C. A. Repenning, pers. com. in lit., 1994; 5) Savage and Russell, 1983; 6) Martin, 1979; 7) H. G. McDonald, pers. com., 1994; 8) McDonald, 1994; 9) J. A. White, pers. com., 1994; 10) Kurten and Anderson, 1980; 11) McDonald, 1993; 12) Repenning, 1992; 13) Jefferson, 1989. and careful salvage efforts by dedicated field per- sonnel. Without salvage efforts, the interpretations presented here would have been impossible to ad- vance, the knowledge of the pre-history of the Elsinore Fault Zone and the Temecula basin would remain limited, and the specimens recovered would be lost along with the sediments that contained them. VERTEBRATE BIOSTRATIGRAPHY Temecula Arkose Previous age assignments of the Temecula Arkose placed the contained faunas within either the Pliocene or Pleistocene. Early efforts based the age of "post-late Pliocene" on taxa including Equus sp., Antilocapra sp. or Tetrameryx sp., lOdocoileus sp. and ?Bison sp., (Mann, 1955, p. 12). Later, an age of 2.7 Ma to 2.2 Ma was proposed based upon the occurrence of Tetrameryx sp. and Nannippus sp. (Golz et al., 1977; Figure 4). Finally, an earlier age of 4.5 Ma was assigned based upon the occurrence of Neotoma (Paraneotoma) sawrockensis in addition to Onychomys gidleyi, Calomys arizonae, Neotoma (Paraneotoma) quadriplicates, Hypolagus vetus and H. edensis and Hemphillian "holdover" taxa including Prothomomys warrensis, Cupidinimus sp. cf. C. bidahochiensis, Copemys vasquezi and Peromyscus valensis (Repenning, 1987; Reynolds and Reynolds, 1993; Figure 4). Although many fossil localities are known from the Temecula Arkose, the majority of these biostratigraphic interpretations were based upon faunas of the Radec localities, from which no Page 34 Biostratigraphy of the Elsinore Fault Zone Pajak et al. complete mammalian faunal list has previously been published (Figure 1; Appendix A). The faunas from Radec reflect a greater span of time than previously accounted for (contra Golz et al, 1977 and Reynolds and Reynolds, 1993). Repenning's (1987) identification of Neotoma (Paraneotoma) sawrockensis from low in the section at Radec indicates an early Blancan age (+ 4.5 Ma) for this unit. The microfauna described by Reynolds and Reynolds (1993) from SBCM 05.002.016 at Radec appears at least in part to support this age assessment. However, the fauna from Radec de- scribed by Golz et al. (1977) indicates a later Blancan age (+ 2.7 - ± 2.2 Ma) for the Temecula Arkose. The first known occurrence of Tetrameryx, as indicated by Golz et al. (1977) who base their age assessment on the discussion in Lindsay et al. (1975), postdates by more than half a million years known occur- rences of Onychomys gidleyi, Calomys arizonae, Neotoma (Paraneotoma) sawrockensis and N. (P.) qimdriplicatus (Reynolds and Reynolds, 1993). The presence in this fauna of the Hemphillian taxa Prothomomys warrensis, Cupidinimus sp. cf. C. bidahochiensis, Copemys vasquezi and Peromyscus valensis, suggested by Reynolds and Reynolds (1993) to be Hemphillian "holdover" taxa, could as easily be employed to infer the presence of an ear- lier faunal component to the Temecula Arkose than any suggested previously (e.g. Golz et al., 1977; Repenning, 1987). In light of these analyses, the contention of Golz et al. (1977, pp. 864-865) that "the fossil verte- brates from the Temecula Arkose have a limited stratigraphic distribution and may be treated as a single assemblage" can no longer be substantiated. The exposures of the Temecula Arkose near Radec appear to cover a substantially greater expanse of time than previously indicated; now potentially ranging from latest Hemphillian throughout the Blancan. Assuming that Golz et al. (1977) and Reynolds and Reynolds (1993) were correct with respect to interpretation of faunas, the age of the Taxa Calomys sp. nr. C. gidleyi Cupidinimus sp. cf. C. bidahochiensis Prothomomys warrensis Onychomys gidleyi Calomys arizonae Neotoma (Paraneotoma ) sawrockensis Neotoma (P.) quadriplicatus Hypolagus sp. <[ Hypolagus vetus <] Hypolagus edensis Ma i 5 «,3. 2 Epoch MIO . PLIOCENE LMA Hemphillian / Blancan XTrv. Reynolds and Reynolds (1993) Hypolagus sp. cf. H. regalis Hypolagus sp. cf. H. limnetus Tetrameryx sp. Nannippus sp. Golzet al. (1977) -------= Hemphillian holdovers Figure 4. Occurrences of taxa in the Radec faunas (from Golz et al., 1977 and Reynolds and Reynolds, 1993). Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 35 Temecula Arkose potentially ranges from approxi- mately 6.0 Ma, based on Hemphillian taxa, to nearly 2.7 Ma, based on the interpretation of Golz et al. (1977) regarding the co-occurrence of Tetrameryx sp. and Nannippus sp. This enormous temporal range may be the result of the preliminary nature of some of these reports. Since there has been little discussion of field relationships or stratigraphic po- sition of the localities, errors resulting from fault juxtaposition or collection practices could poten- tially have been overlooked. A possible future reso- lution to this problem would involve establishing a stratigraphic framework, increased locality control, and possibly radiometric dating of specific hori- zons. Additional sampling from clearly delimited loci with more detailed and accurate control of stratigraphic and field relationships must be ac- complished before additional interpretations are made. Unnamed Sandstone As noted above, previous authors (Kennedy, 1977; Repenning, 1987; and Reynolds et al., 1991) employed local exposures of the Bishop Ash (0.758± 0.002 Ma) at Chaney Hill as a "ballpark" external age control for outcrops of the unnamed sandstone near Murrieta (Figure 2). However, the outcrop at Chaney Hill is structurally isolated and cannot be stratigraphically correlated to fossil localities in the unnamed sandstone. An ash horizon tentatively correlated with the Bishop Ash was reported by Reynolds et al. (1991) and was placed in strati- graphic context with fossil localities. Unfortunately, no petrographic analyses or radiometric dates of this ash horizon are available and its relationship to the Bishop Ash remains indeterminate (Bell, 1993; Scott and Cox, 1993). Until the Bishop Ash is pre- cisely identified within the unnamed sandstone the age of the unnamed sandstone throughout its ex- tent is best determined from biostratigraphic analy- ses. A site by site examination of taxa from the Murrieta area, including reviews of published ac- counts and unpublished mitigation reports, denotes the presence of three distinct biostratigraphic fau- nal units within the unnamed sandstone (contra Reynolds and Reynolds, 1990a, Reynolds et al., 1990, 1991; Scott and Cox, 1993) (Figure 5). Each faunal unit is characterized by taxa unique to that unit. Additional taxa may occur in more than one unit. These three units are informally designated (from oldest to youngest) the Paraneotoma unit, the Mimomys unit and the Microtus /Mammuthus unit. The oldest faunal unit, the Paraneotoma unit, is Blancan in age and is characterized by the occur- rence of Paraneotoma fossilis. The second unit, the Mimomys faunal unit, is also Blancan in age and is recognized by Mimomys (Ophiomys) parvus. The youngest faunal unit, the Microtus /Mammuthus faunal unit, contains faunas representative of the Irvingtonian and is defined by the occurrence of either Microtus sp. or Mammuthus sp. There is little overlap between faunas with the exception of Equus bautistensis and Tetrameryx sp., from both the Mimomys and Microtus /Mammuthus faunal units (Figure 5). These overlapping taxa provide transi- tional elements between the faunal units (contra Reynolds et al., 1991). Localities SBCM 05.006.083 and 05.006.084 (Figure 2) are representative of the Paraneotoma fau- nal unit. These localities yielded a small combined vertebrate fauna (NISP = 69; see Appendix A) which includes several upper and lower molars referred to Paraneotoma fossilis by Reynolds and Reynolds (1990a) and Reynolds et al.(1990, 1991), in associa- tion with jaws and teeth of Sigmodon sp. (Figure 5). P. fossilis has also been recovered from the Coso Mountains, Inyo County, California, in association with Mimomys (Cosomys) primus; this locality has been dated to 3.0 Ma (Bacon et al., 1979; Repenning, 1987). Tomida (1987) reported P. fossilis in the Duncan Basin, Arizona, a fauna roughly correlated with the middle Gauss chron (= + 3.0 Ma). Finally, Repenning (1987) indicates that P. fossilis ranges in age from Blancan III to IV (approximately 3.5 Ma to 2.5 Ma) (Figure 3). The presence of Sigmodon sp. from both the Paraneotoma and Mimomys faunal units suggests that the youngest age of the Paraneotoma faunal unit is constrained by the earli- est age of the Mimomys unit (see below); thus the total age range for the Paraneotoma unit extends from approximately 3.5 Ma to at most 2.2 ±0.1 Ma (Figure 5). The Mimomys faunal unit, characterized by the occurrence of Mimomys (Ophiomys) parvus, is represented by at least six localities from the Murrieta area (Figures 2 and 5), three of which are discussed below. Locality SBCM 05.006.089 yielded a vertebrate fauna (NISP = 61; see Appendix A) including Mimomys (Ophiomys) parvus in associa- tion with Sigmodon sp. (Reynolds and Reynolds, 1990a; Reynolds et al., 1991). This locality was originally considered (Reynolds and Reynolds, 1990a; Reynolds et al., 1991) to comprise part of a composite fauna (the Nutmeg faunas; Appendix A) which also included the sites now assigned to the Paraneotoma faunal unit. Paraneotoma fossilis does Page 36 Biostratigraphy of the Elsinore Fault Zone Pajak et al. Ma | 3 , 2 | 1 0.5 0.01 Epoch PLIOCENE PLEISTOCEN E H. LMA B 1 a n c a n / Irvingtonian Rib Faunal Unit ? | Paraneotoma t Mimomys t M /M i ? ? Localities 1, 2, 3,4,5, 6,7,8, 9, 10, 11, 12, 13 Taxa Paraneotoma fossilis Megalonyx leptostomus Megalonyx wheatleyi Neotoma sp. cf. N. "irvingtonensis Hypolagus sp. — Prodipodomys sp. Mimomys (O.) parvus Sigmodon minor Platygonus bicalcaratus Tetrameryx sp. Equus bautistensis Paramylodon harlani Microtus sp. Arctodus simus Mammuthus sp. Smilodon fa talis Tapirus californicus o o -o— -o> -o—o -E3- - ¦E9-E3-Q- ------------E!-------- —IS)—ED--------- t£t- = Pauba Formation M /M = Microtus /Mammuthus unit Paraneotoma unit 0= Mimomys unit -------- = Range from Fig. 3 (see for reference) -------= Range Estimated E9 = Microtus /Mammuthus unit A = Pauba Formation Locality ? = Faunal Occurrence Unknown Figure 5. Locality and taxa correlation chart for the unnamed sandstone. Faunal unit names are informal and the localities are arranged roughly from the northwest to the southeast with the exception of USGS M1476 (see Figure 2). Note that the chronologic and stratigraphic position of each locality is approximate. Some localities may overlap in both time and stratigraphic position. (See Figure 2 caption for locality number reference). not occur at SBCM 05.006.089 nor does it occur in direct association with Mimomys (Ophiomys) parvus elsewhere in the Murrieta area (contra Reynolds and Reynolds, 1990a and Reynolds et al., 1991). Therefore, localities which have yielded M. (O.) parvus comprise faunas different from those in the Paraneotoma unit. Mimomys (O.) parvus has been dated to possibly 2.3 - 2.2 Ma from the Vallecito Creek faunal succession of the Anza Borrego Desert in San Diego County, California (Repenning et al., 1995). The date of 2.2 ± 0.1 Ma is employed to constrain the earliest age of the Mimomys faunal unit based on the date of possible occurrence of M. (O.) parvus at Vallecito Creek. SBCM 05.006.155, of the Mimomys faunal unit, produced a large assemblage (NISP = 242; see Ap- pendix A) including Megalonyx wheatleyi or M. leptostomus, Equus sp. cf. E. bautistensis, and Platygonus bicalcaratus in association with Hypolagus sp., Prodipodomys sp., Mimomys (Ophiomys) parvus (= Clethrionomys sp. of Reynolds et al., 1990, 1991) and Sigmodon minor (Reynolds et al., 1990, 1991; Scott and Cox, 1993). Hypolagus sp., Prodipodomys sp., Mimomys (Ophiomys) parvus and Sigmodon mi- Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 37 nor are generally considered Blancan forms, al- though they also occur in early Irvingtonian faunas (Martin, 1979; Lundelius et al., 1987; Repenning 1987, pers. com., 1993, 1994; Tomida, 1987; J. A. White, pers. com., 1994; Figure 3). Metric analyses of the specimen identified (Reynolds et al., 1991) as the Irvingtonian taxon M. wheatleyi indicate that the specimen is small for M. wheatleyi and falls within the size range of the Blancan taxon M. leptostomus (H. G. McDonald, pers. com. to E. Scott, 1994). Since this specimen shares some characteristics of both species, it could be referred to either taxon (H. G. McDonald, pers. com. to E. Scott, 1994). SBCM 05.006.155, originally considered to be Irvingtonian in age (Reynolds et al., 1991) is actually probably late Blancan. USGS vertebrate locality M1476 (Figure 2) contains specimens recovered from the surface of a borrow pit. Repenning (1987) originally reported Clethrionomys sp. and Microtus califomicus from this locality, indicating an early Irvingtonian age (Irvingtonian II age of Repenning, 1987). However, upon re-examination of the Clethrionomys specimen, an M,, Repenning (pers. com. in lit. 1994) identified the tooth as IMimomys (Ophiomys) parvus. The re- port of Microtus califomicus is also in error; the spe- cies is not present in M1476. Instead, ?M. (O.) parvus is associated with a nearly complete mandible with Mj through M3 and an isolated M1 of Neotoma sp. These teeth do not resemble Neotoma (Paraneotoma), but instead are similar to fossil remains of Neotoma sp. from Irvington (Repenning pers. com. in lit. 1994). The age of locality M1476 is probably younger than 1.5 Ma based in part on the presence of Neotoma sp. cf. N. "irvingtonensis", which can be no older than about 1.6 Ma, and the youngest oc- currence of M. (O.) parvus from the Froman Ferry fauna of Idaho at 1.5 Ma (Repenning et al., 1995). This places the upper age of the Mimomys faunal unit near 1.5 Ma; the entire possible range for the unit is 2.2 ± 0.1 Ma to + 1.5 Ma (late Blancan to earliest Irvingtonian). Two localities, SBCM 05.006.301 and 05.006.303, contain taxa characteristic of the Pleis- tocene Microtus IMammuthus faunal unit (Figure 2). Locality SBCM 05.006.301 produced a large verte- brate fauna (NISP = 461; see Appendix A) including Microtus sp., Equus bautistensis, and Mammuthus sp. Similarly, SBCM 05.006.303 yielded a substantial fauna (NISP = 233; see Appendix A); Microtus sp., Equus bautistensis, Arctodus simus, and possibly Tetrameryx sp. distinguish this assemblage (Reynolds et al., 1991; Scott and Cox, 1993). The earliest recorded occurrence of Microtus west of the Rocky Mountains, at ± 1.6 Ma, is from the Vallecito Creek faunal succession of the Anza Borrego Desert, California (Lundelius et al., 1987; Repenning, 1987; Repenning et al., 1995). Mammuthus is not recorded from this locality; how- ever, this taxon is recorded as early as +1.4 Ma west of the Rocky Mountains, from the Bruneau Forma- tion of Idaho (Lundelius et al., 1987). These dates suggest that the earliest date for the Microtus / Mammuthus faunal unit in Murrieta can be no older than ±1.6 Ma. If the ash reported by Reynolds et al. (1991) is eventually confirmed as Bishop Ash, then the age of the youngest part of the unnamed sand- stone potentially ranges from +1.6 Ma to ± 0.75 Ma. Pauba Formation Salvage efforts have recently yielded the most extensive fossil fauna yet known from sediments mapped by Kennedy (1977) as the Pauba Forma- tion. This fauna was recovered from sediments east of Interstate 15 and south of Santa Gertrudis Creek (SBCM 05.006.378; Figure 2; Appendix A). Numer- ous discrete field localities, currently under indi- vidual examination by Pajak, were excavated from the fall of 1991 to the spring of 1992 and were subsumed under a single locality number, SBCM 05.006.378. This composite locality yielded a verte- brate fauna (NISP = 361; see Appendix A) including Paramylodon harlani, Thomomys sp., Microtus sp., Smilodon fatalis, Mammuthus sp. cf. M. meridionalis or M. imperator, Equus bautistensis, Tapirus califomicus, Odocoileus sp., and Antilocapra sp. (Bowden and Scott, 1992; Scott, 1992; Pajak, 1993, 1994). This composite locality is Pleistocene in age on the basis of the occurrence of Microtus sp. and Smilodon fatalis; taxa indicative of an earlier Pleis- tocene age include Mammuthus sp. cf. M. meridionalis or M. imperator and Equus bautistensis, suggesting a probable Irvingtonian age. As stated, previous investigators (Jefferson, 1991; Reynolds et al., 1991; McDonald, 1993; Mor- gan, pers. com., 1994) have proposed a Rancholabrean age for the Pauba Formation. This interpretation cannot be supported. The most con- vincing argument for a Rancholabrean age, the re- port of Bison, as recorded by Jefferson (1991) from a mitigation report, is erroneous. The specimen in question, a single partial humerus in the collection of the Natural History Museum of Los Angeles County, has been reexamined and re-identified as Paramylodon harlani. No definitive occurrences of Bison from the Pauba Formation have been demon- strated. Page 38 Biostratigraphy of the Elsinore Fault Zone Pajak et al. Other evidence in favor of a Rancholabrean age for the Pauba Formation is also equivocal. The age assessment advanced by Reynolds et al. (1991) was based primarily upon the superposition of the Pauba Formation to the unnamed sandstone. This evidence is insufficient to specify a particular land mammal age. Likewise, the morphometric analysis of Paramylodon harlani, which suggested that speci- mens of this taxon from the Pauba Formation were more similar in size to Rancholabrean specimens than to Irvingtonian records (McDonald, 1993) can- not be applied definitively. Although the speci- mens of P. harlani from this formation are larger than many early Pleistocene records, some earlier Rancholabrean occurrences, particularly those from American Falls, Idaho, equal the size of later Rancholabrean specimens and the specimens from the Pauba Formation. As a caveat, however, McDonald (1993, p. 102) noted that P. harlani might have "already achieved its maximum size by the Irvingtonian-Rancholabrean transition ca. 500,000 BP" and that it may not be possible to distinguish between early and late Rancholabrean individuals using size as the only criterion. Finally, radiocarbon dates of 40,300 yr. B.P. and 33,470 yr. B.P. obtained from a peat layer dis- covered by M. Morgan (pers. com., 1994) cannot be correlated directly to the fossil fauna, since the pre- cise stratigraphic relationship of the peat layer to the surrounding sediments has not been reliably established. The Rancholabrean land mammal age is de- fined by the presence of Bison (Savage, 1951; Lundelius et al., 1987). This taxon has not been recognized from the Pauba Formation. This ab- sence is not considered to be geographic in nature since Bison was present in the vicinity during the late Pleistocene. Two species of Bison, B. antiquus and B. latifrons, are present in abundance in Rancholabrean sediments from the Domenigoni Valley, located only 15 km northeast of Temecula (Springer and Scott, 1994). The absence of Bison from the Pauba Formation is not considered to have an ecological basis either. The Pauba Formation is dominated by presumed grazing animals, notably the horse Equus bautistensis (Scott, 1992) and Camelops sp., suggesting that grasslands, the pre- ferred modern habitat of Bison, could have domi- nated the environment. Therefore, the absence of Bison from the Pauba Formation is interpreted as support for the argument that the sediments were deposited in the Irvingtonian prior to the immigra- tion of Bison. Other elements of the fauna also suggest an Irvingtonian age. The mammoth remains from the formation (SBCM 05.006.378) have been tentatively assigned to Mammuthus sp. cf. M. meridionalis (Pajak, 1994) and Mammmuthus sp. cf. M. imperator (Reynolds et al., 1991). M. meridionalis is a primitive mammoth and is suggestive of the early Pleistocene while M. imperator is potentially middle to late Pleis- tocene in age (Maglio, 1973). Equus bautistensis is also considered to be an early Pleistocene taxon (Frick, 1921; Savage, 1951; Kurten and Anderson, 1980). Suggestions that E. bautistensis survived into the Rancholabrean, specifically, that the taxon was present in the fauna from the late Pleistocene as- phalt deposits at Rancho La Brea (as stated in Scott, 1992), are now considered to be incorrect based upon new fossil material (E. Scott, pers. obs.). A late Irvingtonian age is therefore endorsed herein for the Pauba Formation in the Murrieta area. A maxi- mum age of the Pauba Formation is based upon the superpositional relationship of the Pauba Forma- tion to the underlying unnamed sandstone. Since a period of erosion separates the end of deposition of the unnamed sandstone (approximately 0.75 Ma) and the beginning of the deposition of the Pauba Formation, a possible beginning of deposition of the Pauba Formation at < 0.6 Ma is suggested. Further research will be necessary to refine the age of the Pauba Formation since all previous work is essentially preliminary. Future efforts should include better stratigraphic control and at- tempts to obtain paleomagnetic samples and radio- metric dates directly from the sediments. Recent investigations suggested that the fine- grained silty-sands reported from the Pauba For- mation, specifically at SBCM 05.006.378, may repre- sent exposures of the unnamed sandstone (Pajak, 1993). However, at present, the contact between the unnamed sandstone and the Pauba Formation re- mains poorly described and may not have been recognized during paleontologic salvage opera- tions. If this interpretation is correct, major revi- sions in the biostratigraphic analysis of the Pleis- tocene sediments of the Temecula basin would be required. SUMMARY AND CONCLUSIONS The age determinations of the sediments of the Temecula basin are based primarily on bio- chronologic interpretations since few radiometric dates are available from these formations and none are directly correlatable to fossil localities. Ongoing research projects have recovered new material and geologic data enabling authors to introduce new Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 39 interpretations of the biostratigraphy of these for- mations (Reynolds and Reynolds, 1990a, 1990b, 1993; Reynolds et al., 1990, 1991; Bell, 1993; Pajak, 1993; Scott and Cox, 1993; Appendix A). The Temecula Arkose was previously as- signed to either the late Pliocene or early Pleis- tocene (Golz et al., 1977) or to the Hemphillian through the early Blancan (Repenning, 1987; Reynolds and Reynolds, 1993). However, these studies are essentially preliminary, and few at- tempts have been made to identify specific hori- zons. In addition, several localities have been com- bined or were erroneously implied to lie within the same approximate horizon. The Radec localities (SBCM 05.002.016 and NHMLAC 1657) originally combined by Reynolds and Reynolds (1993) are near one another, but are not from the same loca- tion (R. Reynolds, pers. com. to E. Scott, 1996) and the contained faunas should not have been com- bined for analysis or interpretation. In this highly tectonic area, individual localities need to be speci- fied and the stratigraphy must be measured and thoroughly described. Future investigators will need to employ careful stratigraphic mapping and precise collecting techniques in order to delineate and refine the age of the Temecula Arkose. The unnamed sandstone may unconformably overlie the Temecula Arkose in the Murrieta area (Kennedy, 1977) and was previously reported to contain at least two faunal components, one Pliocene and one Pleistocene (Reynolds and Reynolds, 1990a; Reynolds et al., 1990a, 1991; Scott and Cox, 1993). The present study, after consider- ation of all published and unpublished material, delimits three informal faunal components: the Paraneotoma unit (later Blancan, + 3.5 Ma to 2.2 ±0.1 Ma), the Mimomys unit (latest Blancan, 2.2 ± 0.1 Ma to ± 1.6 Ma) and the Microtus/Mammuthus unit (early Irvingtonian, ± 1.6 Ma to ± 0.75 Ma). The upper limit of the Microtus /Mammuthus unit may be established in part by the presence of Bishop Ash (0.785 ± 0.002 Ma), but the identification of the ash associated with the fossils is tentative and uncon- firmed. Until a more complete stratigraphic frame- work is provided and additional microvertebrate localities are recovered, these faunal units must be considered tentative. Finally, the Pauba Formation has been deter- mined to date to the late Irvingtonian (< 0.6 Ma to > 0.12 Ma) based on superposition to the unnamed sandstone, the absence of Bison, and the occurrence of early Pleistocene taxa, such as Mammuthus sp. cf. M. meridionalis and Equus bautistensis. ACKNOWLEDGMENTS The present review was motivated primarily by the early efforts of Robert E. Reynolds, Curator of Earth Sciences (SBCM), whose former salvage activities produced much of the fossil material re- viewed and reinterpreted herein. The authors thank Kathleen B. Springer, Project Manager of the Pale- ontologic Resource Assessment Program (SBCM) and Rodney E. Raschke and Marilyn Morgan, Prin- cipal Investigators of RMW Paleo Associates, for providing fossils and for use of materials and infor- mation under their supervision. Numerous field and laboratory personnel are responsible for generating the fossils from the Temecula basin; these individuals include Phillip Allen, James Bowden, Robert Burns, Marnie Crook, Harley Garbani, Patrick Heald, Quintin Lake, Chris- topher Morgan, Mark Roeder, Teena Searl, Juanita Shinn, David Stevens, Steven Wakefield and Diana Weir. All of these individuals are thanked for their time and patient effort. Scott G. Springer, formerly of the SBCM, plotted the resource localities and provided extensive locality data for use in this study. Sam McLeod and J. D. Stewart of the NHMLAC are thanked for access to the collections under their care. The authors extend special thanks to Charles A. Repenning and Richard L. Reynolds both for identification of many of the fossils from the Murrieta/Temecula area and for many helpful dis- cussions. We are grateful to C. A. Repenning for his thorough and insightful reviews of our paper. We also thank James I. Mead, Geraldine E. Swartz and an anonymous reviewer for comments on an earlier version of this report. H. G. McDonald, D. E. Sav- age and J. A. White provided valuable input. Thanks also to Ted Fremd for use of the CorelDRAW program for previous versions of Fig- ures 1 and 2. Finally, thanks are due to Camille Evans for the use of her Macintosh PC. LITERATURE CITED Bacon, C. R., D. M. Giovannetti, W. A. Duffield and G. B. Dalrymple. 1979. New constraints on the age of the Coso Formation, Inyo County, California. Geological Society of America Ab- stracts with Programs 11(3):67. Bell, C. J. 1993. Fossil lizards from the Elsinore Fault Zone, Riverside County, California. In New additions to the Pleistocene vertebrate record of California (R. G. Dundas and D. J. Long, eds.). PaleoBios 15(2):18-26. Bowden, J. K. and E. Scott. 1992. New record of Smilodonfatalis (Leidy), 1868 (Mammalia; Car- Page 40 Biostratigraphy of the Elsinore Fault Zone Pajak et al. nivora; Felidae) from Riverside County, Cali- fornia. 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Whistler, eds.). San Bernardino County Museum Association Quarterly 38(3&4):37-40. Sarna-Wojcicki, A. M., H. R. Bowman, C. E. Meyer, P. C. Russell, M. J. Woodward, G. McCoy, J. J. Rowe, Jr., P. A. Baedecker, F. Asaro, and H. Michael. 1984. Chemical analysis, correla- tions, and ages of upper Pliocene and Pleis- tocene ash layers of east-central and Southern California. United States Geological Survey Professional Paper 1293:1-39. Savage, D. E. 1951. Late Cenozoic vertebrates of the San Francisco Bay region. University of California Publications in Geological Sciences 28:215-314. Savage, D. E. and D. E. Russell. 1983. Mammalian Paleofaunas of the World. London: Addison- Wesley Publishing. 432 pp. Scott, E. 1992. New specimens of Pleistocene Equus (Mammalia, Perissodactyla, Equidae) from Riverside County, California. Journal of Ver- tebrate Paleontology 12(Supplement to 3):51A. Scott, E. and S. M. Cox. 1993. Arctodus simus (Cope), 1879 from Riverside County, Califor- nia. In New Additions to the Pleistocene Ver- tebrate Record of California (R. G. Dundas and D. J. Long, eds.). PaleoBios 15(2):27-36. Springer, K. B. and E. Scott. 1994. First record of late Pleistocene vertebrates from the Domenigoni Valley, Riverside County, Cali- fornia. Journal of Vertebrate Paleontology 14(Supplement to 3):47A. Tomida, Y. 1987. Small mammal fossils and corre- lation of continental deposits, Safford and Duncan basins, Arizona, USA. Tokyo: Na- tional Science Museum. 141 pp. Page 42 Biostratigraphy of the Elsinore Fault Zone Pajak et al. APPENDIX A. Mammalian faunal lists for selected paleontologic localities from the Murrieta/ Temecula area, including localities discussed in the text. Generally, only those taxa identified to the family level or below are listed. Omitted locality numbers lack identifications to this level, or else are from projects outside of the Murrieta /Temecula area. Mollusks, fish, amphibians, reptiles, and birds are not included in these lists. Identifications prior to 1992 were primarily made by R. L. Reynolds and R. E. Reynolds; those after 1992 by R. L. Reynolds and E. Scott. Additonal identifications were also made by several workers including L. D. Agenbroad, C. J. Bell, S. M. Cox, L. P. Fay, M. Morgan, A. F. Pajak, R. E. Raschke, and C. A. Shaw. Published citations for the identifica- tions follow each taxon or locality number. Equid identifications are preliminary (E. Scott, pers. obs.). The number of identified specimens (NISP) is provided for each locality. NISP = NA indicates that the NISP is not available. Composite faunas (those faunas in which specimens from two or more field sites were recorded in the locality database of the SBCM under a single locality number, follow- ing that institution's prior practice of lumping sites on the basis of geographic proximity) are denoted with a C followed by the number of field sites present. Locality data is available from the Regional Paleontologic Locality Inventory of the SBCM. TEMECULA ARKOSE LOCALITIES SBCM 05.002.016 (Radec) (NISP = NA) (Identifications, Reynolds and Reynolds, 1993) Hypolagus sp. (sm) Neotoma (Paraneotoma) quadriplicatus (sm) Neotoma (Paraneotoma) ? nr. taylori Prothomomys sp. (lg) cf. P. warrensis Perognathus sp. Cupidinimus sp. cf. C. bidahochiensis Calomys arizonae Copemys vasquezi 7 Copemys sp. Peromyscus valensis Sigmodon minor medins Onychomys gidleyi IParonychomys sp. NHMLAC 1657 (Radec) (NISP = NA) NOTE: These identifications were made as initial iden- tifications for cataloguing purposes and have not been verified (S. A. McLeod, pers. com., 1996) Hypolagus sp. Perognathus sp. Neotoma sp. Sigmodon sp. Equus sp. Antilocapridae Mammalian Faunal List of Golz et al. (1977) from Radec (NISP = NA) Talpidae Xenarthra (size of Nothrotheriops) Hypolagus cf. H. limnetus Hypolagus cf. H. regalis Sciuridae Perognathus sp. cf. Dipodomys sp. Neotoma sp. Sigmodon sp. Cricetinae (sm) Canis (size of C. latrans) Taxidea sp. Felis ?Lynx sp. Proboscidea Equus sp. Nannippus sp. ICamelops sp. Lamini Camelidae Odocoileus sp. Tetrameryx sp. SBCM 05.002.001 (Vail Lake) (NISP = NA) (Identifica- tions, Reynolds and Reynolds, 1993) Hypolagus sp. cf. H. edensis Hypolagus sp. (sm) Hypolagus sp. cf. H. vetus Neotoma (Paraneotoma) sawrockensis (Identification, C. A. Repenning, pers. com. to R. E. Reynolds) Prothomomys sp. (lg) cf. P. warrensis Perognathus sp. Calomys sp. nr. C. gidleyi SBCM 05.002.006 (Shamrock) (NISP = NA) (Identifica- tions, Reynolds and Reynolds, 1993) Hypolagus sp. (sm) Neotoma (Paraneotoma) sawrockensis (Identification, C. A. Repenning, pers. com. to R. E. Reynolds) Prothomomys sp. (lg) cf. P. warrensis Thomomys sp. cf. T. gidleyi Thomomys sp. cf. T. bottae Cupidinimus sp. cf. C. bidahochiensis Calomys sp. nr. C. gidleyi Copemys vasquezi Peromyscus valensis Waronychomys sp. SBCM 05.002.051 (Butterfield Valley) (NISP = NA) (Iden- tifications, Reynolds and Reynolds, 1993) Hypolagus sp. cf. H. edensis Hypolagus sp. (sm) Neotoma (Paraneotoma) sawrockensis (Identification, C. A. Repenning, pers. com. to R. E. Reynolds) Prothomomys sp. (lg) cf. P. warrensis Thomomys sp. cf. T. gidleyi Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 43 UNNAMED SANDSTONE LOCALITIES SBCM 05.006.072 (NISP = 36) (Nutmeg faunas of Reynolds and Reynolds, 1990a; Reynolds, et al, 1991) Leporidae Sciuridae Thomomys sp. Perognathus sp. Paraneotoma fossilis (Identification, C. A. Repenning; see Reynolds and Reynolds, 1990a) Sigmodon sp. cf. Peromyscus sp. Eqims sp. SBCM 05.006.073 (NISP = 30) (Nutmeg faunas of Reynolds and Reynolds, 1990a; Reynolds, et al., 1991) Leporidae Thomomys sp. ?Dipodomys sp. Sigmodon sp. Peromyscus sp. SBCM 05.006.076 (NISP = 2) (Nutmeg faunas of Reynolds and Reynolds, 1990a; Reynolds, et al., 1991) Leporidae Neotoma sp. SBCM 05.006.078 (NISP = 1) cf. Antilocapra sp. SBCM 05.006.083 (NISP = 52) (Nutmeg faunas of Reynolds and Reynolds, 1990a; Reynolds, et al., 1991) ?Scapanns sp. Leporidae IDipodomys sp. Perognathus sp. Paraneotoma fossilis (Identification, C. A. Repenning; see Reynolds and Reynolds, 1990a) Sigmodon sp. Equussp. SBCM 05.006.084 (NISP = 17) (Nutmeg faunas of Reynolds and Reynolds, 1990a; Reynolds, et al., 1991) Lepus sp. IThomomys sp. Paraneotoma fossilis (Identification, C. A. Repenning; see Reynolds and Reynolds, 1990a) Sigmodon sp. SBCM 05.006.085 (NISP = 1) Equussp. SBCM 05.006.089 (NISP = 61) (Crowell David faunas of Reynolds and Reynolds, 1990a; Reynolds, et al., 1991) Sylvilagus sp. Leporidae Thomomys sp. (cf. T. gidleyil) ?Dipodomys sp. ?Perognathus sp. Sigmodon minor Ondatra sp. Mimomys (Ophiomys) parvus (Identification, C. A. Repenning; see Reynolds and Reynolds, [1990a]) Equus sp. (Ig) SBCM 05.006.090 (NISP = 11) Thomomys sp. ?Sigmodon sp. Peromyscus sp. Mimomys (Ophiomys) parvus (Identification, C. A. Repenning; see Reynolds and Reynolds, [1990a]) Equus sp. (Ig) SBCM 05.006.135 (NISP = 1) cf. Sigmodon sp. SBCM 05.006.138 (NISP = 33) (Reynolds et al., 1991) Sylvilagus sp. Leporidae (lg & sm) Thomomys sp. Prodipodomys sp. Dipodomys sp. Neotoma sp. Sigmodon minor Microtus sp. Equus sp. cf. E. bautistensis (Identification, E. Scott; formerly identified as Equus sp. by Reynolds et al. [1991] (NOTE: sediment sample from this locality is listed in field notes as "possibly contaminated." SBCM 05.006.143 (NISP = 257) (C, 6) (Reynolds et. al, 1991) Microchiroptera Sylvilagus sp. Leporidae (lg) Sciuridae (lg & sm) Thomomys bottae Perognathinae Dipodomys sp. INeotoma sp. Onychomys torridus 1 Sigmodon sp. Microtus californicus cf. Vulpes macrotis ICanis latrans cf. Mephitis sp. Equus sp. Camelops sp. Odocoileus sp. SBCM 05.006.145 (NISP = 1) Equus sp. (lg) SBCM 05.006.146 (NISP = 12) (Reynolds et al., 1991) Dipodomys sp. Cricetidae Equus bautistensis (Identification, E. Scott; formerly iden- tified as Equus sp. by Reynolds et al. [1991]) SBCM 05.006.148 (NISP = 27) (Reynolds et al., 1991) Page 44 Biostratigraphy of the Elsinore Fault Zone Pajak et al. Leporidae (sm) Thomomys bottae cf. Perognathns sp. Dipodomys sp. Peromyscus sp. Neotoma sp. Mimomys (Ophiomys) parvus (Identification, C. A. Repenning; see Reynolds and Reynolds, [1990a]) Sigmodon sp. SBCM 05.006.149 (NISP = 4) Leporidae (sm) Thomomys sp. SBCM 05.006.150 (NISP = 1) Thomomys sp. SBCM 05.006.151 (NISP = 6) (Reynolds et al, 1991) Thomomys sp. ?Prodipodomys sp. Neotoma (Paraneotoma) sp. Neotoma sp. SBCM 05.006.152 (NISP = 6) (Reynolds et al, 1991) Thomomys bottae SBCM 05.006.154 (NISP = 72) (Reynolds et al., 1991) Leporidae (lg & sm) Thomomys bottae Dipodomys sp. Neotoma sp. Sigmodon minor Eauus sp. (sm) SBCM 05.006.155 (NISP = 242) (C, 2) (CAR 2-C parcel of Reynolds et al., 1991) Megalotiyx wheaileyi or M. leptostomus Hypolagus sp. Sylvilagus sp. Eutamias sp. Spermophilus sp. aff. S. beecheyi Geomys sp. Thomomys bottae ? Prodipodomys sp. Dipodomys sp. Perognathus sp. Mimomys {Ophiomys) parvus (Identification, C. A. Repenning; formerly identified as Clethrionomys by Reynolds et al. [1991]; see Scott and Cox [1993]) Reithrodontomys sp. Neotoma (Paraneotoma) sp. Sigmodon minor Coendou sp. cf. Canis latrans Mustela sp. Equus bautistensis (Identification, E. Scott; formerly iden- tified as Equus sp. by Reynolds et al. [1991]) Equus sp. (sm) Platygonus bicalcaratus ?Tetrameryx sp. Antilocapra sp. Camelidae (sm) Odocoileus sp. SBCM 05.006.156 (NISP = 6) (Reynolds et al., 1991) Leporidae (sm) Thomomys sp. Mimomys (Ophiomys) parvus (Identification, C. A. Repenning; formerly identified as Clethrionomys by Reynolds et al. [1991]; see Scott and Cox [1993]) SBCM 05.006.157 (NISP = 19) (Reynolds et al., 1991) Leporidae (sm) Thomomys sp. Prodipodomys sp. Dipodomys sp. Peromyscus sp. Sigmodon sp. SBCM 05.006.158 (NISP = 6) (CAR 2-C parcel of Reynolds et al., 1991) Leporidae (sm) Neotoma sp. SBCM 05.006.159 (NISP = 63) (Reynolds et al., 1991) Sorex sp. Hypolagus sp. Sylvilagus sp. Eutamias sp. Thomomys bottae Dipodomys sp. Neotoma sp. Sigmodon minor cf. Canidae SBCM 05.006.184 (NISP = 6) cf. Scapanus sp. Leporidae (lg & sm) cf. Dipodomys sp. Peromyscus sp. cf. Sigmodon sp. ?Equus sp. SBCM 05.006.185 (NISP = 1) Equus sp. cf. E. bautistensis (Identification, E. Scott) SBCM 05.006.186 (NISP = 1) Equus sp. (lg) SBCM 05.006.187 (NISP = 13) (Reynolds et al, 1991) Leporidae (sm) Thomomys sp. Dipodomys sp. Reithrodontomys sp. Equus sp. (lg) SBCM 05.006.189 (NISP = 3) Thomomys sp. Cricetidae (sm) Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 45 SBCM 05.006.196 (NISP = 1) Eqitus sp. (Ig) SBCM 05.006.203 (NISP = 1) (Reynolds et al, 1991) Equus sp. SBCM 05.006.204 (NISP = 11) (Reynolds et al, 1991) Leporidae (sm) Thomomys bottae Mimomys (Ophiomys) parvus (Identification, C. A. Repenning; formerly identified as Clethrionomys by Reynolds et al. [1991]; see Scott and Cox [1993]) Sigmodon sp. Odocoileus sp. SBCM 05.006.207 (NISP = 105) Sylvilagus sp. Leporidae (med.) Thomomys sp. cf. T. bottae Perognathus spp. (Ig & sm) Dipodomys spp. (Ig & sm) Peromyscus sp. Microtus californicus Mammut sp. Equus sp. cf. E. bautistensis (Identification, E. Scott) SBCM 05.006.208 (NISP = 5) Leporidae (sm) Mammuthus sp. SBCM 05.006.296 (NISP = 1) Equus sp. (sm) SBCM 05.006.299 (NISP = 1) Leporidae (sm) SBCM 05.006.300 (NISP = 2) (Morrison parcel of Reynolds et al., 1991) Equus sp. (Ig) SBCM 05.006.301 (NISP = 461) (C, 42) (Morrison parcel of Reynolds et al, 1991) Scapanus sp. Sylvilagus sp. Leporidae (lg) Sciuridae (sm) Thomomys bottae Perognathus spp. (Ig & sm) Dipodomys spp. (lg & sm) Neotoma sp. Microtus sp. Canis sp. Felidae cf. Mammuthus sp. Equus bautistensis (Identification, E. Scott; formerly iden- tified as Equus sp. by Reynolds et al. [1991]) Camelidae SBCM 05.006.303 (NISP = 233) (C, 11) (Morrison parcel of Reynolds et al, 1991) Scapanus sp. Leporidae Sciuridae Thomomys bottae Perognathus spp. (lg & sm) Dipodomys spp. (lg & sm) Peromyscus sp. Neotoma sp. Microtus sp. Vulpes sp. Arctodus simus (Identification, Scott and Cox, 1993) Mammuthus sp. Equus bautistensis (Identification, E. Scott; formerly iden- tified as Equus sp. by Reynolds et al. [1991]) Camelops sp. Hemiauchenia sp. ?Tetrameryx sp. SBCM 05.006.305 (NISP = 87) (C, 5) Leporidae (sm) Thomomys bottae Perognathus sp. Dipodomys sp. Neotoma sp. Microtus sp. Canidae (sm) E^ums bautistensis (Identification, E. Scott) Camelidae SBCM 05.006.307 (NISP = 3) Leporidae (sm) Thomomys sp. SBCM 05.006.309 (NISP = 137) Hypolagus sp. Thomomys bottae Perognathus spp. (lg & sm) Dipodomys spp. (lg & sm) Peromyscus sp. Canidae SBCM 05.006.310 (NISP = 18) (C, 2) Leporidae Thomomys bottae Perognathus sp. Dipodomys sp. Peromyscus sp. Equus sp. SBCM 05.006.311 (NISP = 39) Leporidae (sm) Sciuridae Thomomys bottae Perognathus sp. (sm) Dipodomys spp. (lg & sm) Neotoma sp. Microtus sp. Equus sp. Page 46 Biostratigraphy of SBCM 05.006.312 (NISP = 138) Leporidae Thomomys bottae Perognathus spp. (lg & sm) Dipodomys spp. (lg & sm) Peromyscus sp. Microtus sp. SBCM 05.006.313 (NISP = 2) Thomomys sp. Perognathus sp. SBCM 05.006.315 (NISP = 310) Sorex sp. Sylvilagus sp. Lepus sp. Sciuridae (lg) Thomomys bottae Perognathus spp. (lg & sm) Dipodomys spp. (lg & sm) Peromyscus sp. Onychomys torridus Neotoma sp. Microtus sp. Taxidea sp. cf. Mammuthus sp. SBCM 05.006.319 (NISP = 1) Neotoma sp. SBCM 05.006.321 (NISP = 56) (C, 12) (Morrison parcel of Reynolds et al, 1991) Dipodomys sp. (sm) Neotoma sp. Equus bautistensis (Identification, E. Scott; formerly iden- tified as Equus sp. by Reynolds et al. [1991]) Camelidae SBCM 05.006.322 (NISP = 3) (C, 3) Equus sp. SBCM 05.006.323 (NISP = 16) (C, 2) ?Scapanus sp. Leporidae (lg) Neotoma sp. Microtus sp. Equus sp. Camelidae (lg) SBCM 05.006.324 (NISP = 6) (Morrison parcel of Reynolds et al., 1991) Equus bautistensis (Identification, E. Scott; formerly iden- tified as Equus sp. by Reynolds et al. [1991]) SBCM 05.006.341 (NISP = 5) (C, 5) Leporidae (sm) Thomomys sp. Dipodomys sp. Equus sp. (lg) Elsinore Fault Zone Pajak et al. SBCM 05.006.342 (NISP = 6) (C, 4) Neotoma sp. Equus sp. (?lg) SBCM 05.006.343 (NISP = 1) Equus bautistensis (Identification, E. Scott) SBCM 05.006.344 (NISP = 1) Dipodomys sp. SBCM 05.006.345 (NISP = 7) Equus sp. (lg) SBCM 05.006.346 (NISP = 2) Equus sp. (lg) SBCM 05.006.350 (NISP = 1) Equus sp. cf. E. bautistensis (Identification, E. Scott) SBCM 05.006.351 (NISP = 3) (C, 2) Equus sp. (lg) cf. Antilocapra sp. SBCM 05.006.353 (NISP = 3) Sylvilagus sp. Thomomys sp. Perognathinae SBCM 05.006.354 (NISP = 1) Equus sp. (lg) SBCM 05.006.364 (NISP = 11) cf. Leporidae (sm) Thomomys bottae Perognathus sp. (lg) Dipodomys sp. (lg) ?Neotoma sp. SBCM 05.006.365 (NISP = 1) Thomomys bottae SBCM 05.006.366 (NISP = 6) Thomomys sp. Dipodomys sp. (sm) INeotoma sp. SBCM 05.006.380 (NISP = 19) (C, 3) Leporidae Thomomys sp. Dipodomys spp. (lg & sm) Peromyscus sp. Neotoma sp. Microtus sp. Equus sp. cf. E. bautistensis (Identification, E. Scott) SBCM 05.006.381 (NISP = 16) (C, 2) Thomomys bottae Dipodomys sp. Pajak et al. Biostratigraphy of the Elsinore Fault Zone Page 47 Neotoma sp. SBCM 05.006.382 (NISP = 12) (C, 3) Equus baiitistensis (Identification, E. Scott) SBCM 05.006.383 (NISP = 2+) (C, 2) Equus sp. (lg) SBCM 05.006.384 (NISP = 5) (C, 3) Thomomys bottae Canis sp. (?Ig) Equus sp. SBCM 05.006.385 (NISP = 2) (C, 2) Thomomys sp. Proboscidea SBCM 05.006.386 (NISP = 9) (C, 4) Equus sp. Camelops sp. ?Hemiauchenia sp. SBCM 05.006.394 (NISP = 10) Leporidae (sm) Thomomys sp. Perognathus sp. (sm) Peromyscus sp. Sigmodon sp. SBCM 05.006.397 (NISP = 111) Soricidae Leporidae (lg & sm) cf. Eutamias sp. (sm) Thomomys sp. IVerognathus sp. (sm) ?Prodipodomys sp. Peromyscus sp. Sigmodon sp. Mimomys sp. SBCM 05.006.539 (NISP = 2) Thomomys sp. SBCM 05.006.540 (NISP = 1) Thomomys sp. SBCM 05.006.545 (NISP = 28) Sylvilagus sp. LepiiS sp. Sciuridae Thomomys sp. Dipodomys sp. (lg) Microtus californicus Equus sp. (lg) SBCM 05.006.546 (NISP = 9) Lepifs sp. Thomomys sp. Dipodomys sp. (lg) cf. Equus sp. (lg) SBCM 05.006.547 (NISP = 13) Sylvilagus sp. Thomomys bottae Peromyscus sp. Neotoma sp. SBCM 05.006.548 (NISP = 9) Sylvilagus sp. Thomomys sp. Perognathus sp. (lg) Neotoma sp. SBCM 05.006.549 (NISP = 46) Sylvilagus sp. Lepus sp. Thomomys sp. Dipodomys sp. (lg) Peromyscus sp. Neotoma sp. Microtus californicus ?Equus sp. (lg) SBCM 05.006.553 (NISP = 2) Dipodomys sp. (lg) SBCM 05.006.556 (NISP = 1) Microtus sp. SBCM 05.006.557 (NISP = 2) Thomomys sp. Dipodomys sp. (lg) SBCM 05.006.593 (NISP = 1) cf. Mammut sp. SBCM 05.006.594 (NISP = 1) Equus sp. (lg) SBCM 05.006.596 (NISP = 6) Equus sp. cf. £. baiitistensis (Identification, E. Scott) SBCM 05.006.598 (NISP = 1) Equus sp. cf. £. baiitistensis (Identification, E. Scott) SBCM 05.006.599 (NISP = 5) Antilocapridae SBCM 05.006.600 (NISP = 2+) Mammut sp. Equns sp. cf. £. baiitistensis (Identification, E. Scott) SBCM 05.006.601 (NISP = 11) Odocoileus sp. Cervidae Antilocapridae (med) SBCM 05.006.602 (NISP = 2) Equus baiitistensis (Identification, E. Scott) Page 48 Biostratigraphy of the Elsinore Fault Zone Pajak et al. Tapirns californicus SBCM 05.006.603 (NISP = 5) (C, 2) IParamylodon harlani Proboscidea SBCM 05.006.604 (NISP = 2) Mammuthus sp. SBCM 05.006.606 (NISP = 9) (C, 8) ? Paramylodon sp. Equus sp. Camelidae SBCM 05.006.607 (NISP = 1) Equus bautistensis (Identification, E. Scott) SBCM 05.006.609 (NISP = 3) (C, 3) Equus sp. cf. E. bautistensis SBCM 05.006.610 (NISP = 1) (C, 3) Equus sp. (lg) SBCM 05.006.611 (NISP = 7) Equus sp. (lg) SBCM 05.006.612 (NISP = 4) Equus sp. (lg) ?Hemiauchenia SBCM 05.006.613 (NISP = 1) Cervidae SBCM 05.006.614 (NISP = 5) (C, 2) Mammuthus sp. Equus sp. cf. E. bautistensis (Identification, E. Scott) Camelidae (lg) SBCM 05.006.615 (NISP = 1) Equus sp. (?sm) SBCM 05.006.616 (NISP = 1) Equus sp. cf. E. bautistensis (Identification, E. Scott) SBCM 05.006.619 (NISP = 1) Equus sp. PAUBA FORMATION LOCALITIES SBCM 05.006.131 (NISP = NA) Mammuthus sp. cf. M. columbi SBCM 05.006.132 (NISP = 7) Leporidae (sm) Thomomys sp. Antilocapridae SBCM 05.006.378 (NISP = 361) (C, 214) Sorex sp. Talpidae Chiroptera Paramylodon harlani (Identification, H. G. McDonald) Sylvilagus sp. Sciuridae Thomomys bottae Perognathus sp. (lg) Dipodomys sp. (lg & sm) ? Peromyscus sp. Neotoma sp. Microtus sp. Canis latrans Mustela sp. Smilodon fatalis (Bowden and Scott, 1992) Mammut americanum Mammuthus sp. cf. M. meridionalis (Identification, L. Agenbroad, A. F. Pajak, and M. Crook; Pajak, 1994) Equus bautistensis (Identification, E. Scott) Tapirus californicus (Pajak, 1993) ?Tayassuidae Camelops sp. cf. Odocoileus sp. cf. Antilocapra sp. SBCM 05.006.390 (NISP = NA; at least 5) (McDonald, 1993) Paramylodon harlani SBCM 05.006.391 (NISP = NA; at least 1) (McDonald, 1993) Paramylodon harlani SBCM 05.006.400 (NISP = 2) ?Cricetidae Camelops sp. SBCM 05.006.401 (NISP = 1) Leporidae (sm) SBCM 05.006.404 (NISP = 1) Thomomys sp. SBCM 05.006.405 (NISP = 87) cf. Scapanus sp. Sylvilagus sp. Leporidae (lg) Thomomys sp. Dipodomys sp. (lg) Peromyscus sp. Neotoma sp. Microtus sp. SBCM 05.006.410 (NISP = 1) cf. Equus sp. (lg) SBCM 05.006.411 (NISP = 34) Leporidae Thomomys sp. Peromyscus sp. Microtus sp. Equus sp. (lg) Pajaketal. Biostratigraphy of the Elsinore Fault Zone Page 49 SBCM 05.006.412 (NISP = 3) Equus sp. cf. E. bautistensis (Identification, E. Scott) SBCM 05.006.414 (NISP = 155) Sorex sp. Sylvilagus sp. Lepus sp. Sciuridae (sm) Thomomys sp. cf. T. bottae Dipodomys spp. (lg & sm) Peromyscus sp. Micro tus sp. ?Carnivora Equus sp. (lg) SBCM 05.006.415 (NISP = 2) Thomomys sp. SBCM 05.006.416 (NISP = 1) Equus sp. (lg) SBCM 05.006.421 (NISP = 8) Equus sp. (lg) SBCM 05.006.424 (NISP = 3) Paramylodon sp. SBCM 05.006.425 (NISP = 1) Equus sp. (lg) SBCM 05.006.551 (NISP = 6) Thomomys sp. Perognathus sp. (lg) Dipodomys sp. (lg) cf. Microtus sp. SBCM 05.006.552 (NISP = 1) Thomomys sp. SBCM 05.006.560 (NISP = 44) Sylvilagus sp. Lepus sp. cf. Sciuridae Thomomys bottae Dipodomys sp. (lg) Neotoma sp. Microtus sp. Oct's sp. cf. O. canadensis SBCM 05.006.562 (NISP = 1) Thomomys sp. SBCM 05.006.566 (NISP = Sylvilagus sp. 1)