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88 & Contributions in Science, Number 520 Squires: Pico Formation Paleontology

Table 2 Depth ranges, substrate preferences, geographic ranges, and faunal provinces of Newhall area Pico Formation extant species.
Meters Substrate Latitudinal range (6N) Refs.
Terebratalia occidentalis 50–250 On hard surfaces 26–23 1
Jupiteria taphria 10–100 In sand and clay 39.5–28.2 2
Pododesmus macroschisma 0–90 On hard surfaces 70.6–27.9 2
Epilucina californica 0–80 Sand and gravel of exposed shorelines 41.8–25 2
Here excavata 25–125 In sand or mud 34.4–27.9 2
Lucinisca nuttalli 10 to 75 In sand or muddy sand 36.7–27.8 into Gulf of Califor- 2
nia to 22.4
Lucinoma annulatum 0–665 In sand of exposed shorelines 60.8–25.7 2
Miltha xantusi 20–150 In sand 22.1 into Gulf of California to 3
Panama (8.3)
Trachycardium (D.) 0–50 In sand or mud, bays and offshore 36.6–27 2
quadragenarium
Callithaca tenerrima 0–30 In gravelly sand 57.1–27.6 2
Compsomyax subdiaphana 2–500 In soft mud 60.8–30.4 + local pop. in Gulf 2
of California (30.3)
Amiantis callosa 0–20 In sand, exposed headlands 34.4–24.8 2
Dosinia ponderosa 0–60 Soft bottoms 27.8 into Gulf of California to 3
Peru (3.5uS)
Saxidomus nuttalli 0–10 In mud or sand, bays and lagoons 40.7–27.7 2
Tresus nuttallii 0–80 In mud, sheltered bays and foreshores 57–24.6 2
Macoma (Rexithaerus) secta 0–100 In silt and sand of bays 54–24.6 2
Macoma nasuta 0–50 In sand or silt, exposed or sheltered 60.2–27.7 2
Leporimetis obesa subtidal–50 In sand 34.5–24.6 2
Tellina (Tellinella) idae 0–100 In sand 34.4–32.7 2
Solen (Ensisolen) sicarius intertidal In sand or mud, sheltered bays 54–30.4 2
Panopea abrupta 0–100 In sand or mud 57.6–33.6 2
?Chaecia ovoidea 0–subtidal Boring into clay, shale, or wood 37.9–27.7 2, 4
Pandora (Heteroclidus) subtidal–50 In mud 49.9–26.2 2
punctuata
Cyathodonta pedroana 9–114 In mud 36.7–24.6 2
Calliostoma splendens ? Rocky areas 35–32.5 5
Chlorostoma gallina form mid tidal Rocky areas 34–25 6
multifilosa
Turritella cooperi 25–100 On sand 37–24 into W side Gulf of 7
California to head of Gulf
Crepidula aculeata intertidal On hard surfaces 42–Chile (30uS) 8
Zonaria (Neobernaya) spadicea sublittoral Under overhung rock ledges 35–28 9
Glossaulax reclusiana 0–50 On sand or mud, common in bays 41.8 into Gulf of California to 10
21.5
Cryptonatica clausa 9–970 On soft bottoms 60–32.5 10
Sinum scopulosum 15–171 On sand or mud, common in bays 36.5–27.6 10
Asperiscala minuticostata 18–137 On sand and broken shells 28 into Gulf of California to 11
Ecuador (0u)
Ocinebrina atropurpurea 0–sublittoral Rocky bottoms 60–30.5 9
Alia tuberosa sublittoral In gravel under kelp 60–25 9
Barbarofusus barbarensis 50–350 m Soft bottoms 36.5–23 7
Callianax baetica 0–offshore On sandy bottoms 55–23 9
Californiconus californicus 0–30 On rock and sand 37.5–24.5 9
Ophiodermella inermis 0–70 Soft bottoms 53–24.5 7
Crockerella conradiana 24–240 Soft bottoms 34–32 7
Acteocina culcitella 0–offshore On sand flats and mudflats in bays 55–27.5 9

References: 1 5 Hochberg, 1994; 2 5 Coan et al., 2000; 3 5 Coan & Scott, 2012; 4 5 Kennedy, 1974; 5 5 Grant and Gale, 1931; 6 5 McLean, personal
communication; 7 5 McLean, 1996; 8 5 Keen, 1971; 9 5 McLean, 1978;10 5 Marincovich, 1977; 11 5 DuShane, 1979.

TAPHONOMY Crepidula aculeata (Gmelin, 1791) (some of which are vertically
stacked). In addition, both species are represented by juvenile and
As mentioned earlier, the shoreface-facies megafauna occurs in adult specimens.
channelized, storm-lag deposits. It is striking how the taxonomic The storm-lag deposits in the upper Pico Formation commonly
composition of one storm-lag deposit differs so much from one represent a mixture of species that lived in different life
that is nearby, in either a lateral or vertical stratigraphic sense. associations on different types of substrate. Occasional large
For example, at LACMIP loc. 17918, Turritella cooperi shells are storm waves raked all these shallow waters and thereby mixed
so abundant that they constitute a coquina bed (with unworn the life associations together. Distance of postmortem transport
specimens). In a storm lag a few meters up section, there are was short based on the presence of paired valves of most of the
relatively few T. cooperi. Instead, there are concentrations of brachiopods and many of the bivalves (e.g., Panopea, Solena,
both the brachiopod Terebratalia hemphilli and the gastropod Myrakeena, Argopecten, Lyropecten) (see Table 1). None of