 Fig. 4, 13A, 14A ). The Santa Cruz Mudstone below the contact consists of interbedded couplets of unconsolidated siltstone and silicified porcelanite. The lower contact of this bonebed is highly irregular, with 20 cm of relief; many burrows (Ophiomorpha) extend up to 2.5 meters below the contact and are infilled with glauconitic sandstone and coarse bonebed debris. The matrix lithology of the bonebed is primarily massive (and burrow-mottled) medium grained, glauconite-rich sandstone (Spm) with occasional granules. Coarse clasts are extraformational porcelanite pebbles and cobbles from the Santa Cruz Mudstone and extrabasinal terrigenous pebbles (and rare cobbles). Cobbles of the Santa Cruz Mudstone often exhibit flask-shaped clam borings identified as Gastrochaenolites (circular aperture with flask-shaped cross section, 1–3 cm long) on all sides, in addition to conchoidal fracturing of many surfaces. Bonebed 1 is an approximately 50 cm thick matrix-supported conglomerate. Coarse clasts and bioclasts are most densely concentrated (matrix supported or loosely packed) in the basal 20 cm thick β-interval, and are increasingly more dispersed within the overlying γ-interval. Cobbles and large bioclasts are almost always in the lower 20 cm and occasionally in contact with the truncated Santa Cruz Mudstone. Lithic gravel and bioclast size decreases upwards. The thickness of this generally tabular bonebed is maintained laterally, and it can be traced laterally along the shoreline for 0.7 km.

Six bonebeds from the Santa Cruz section of the Purisima Formation were studied in detail ( Table 4 ). Several other bonebeds were observed – two in the middle of section 1, and a third within section 3, several meters above Bonebed 5. Bonebeds 1, 4, 5, and 6 are exposures of the massive pebbly sandstone (Spm) lithofacies, whereas Bonebed 2 is an exposure of the massive pebbly mudrock (Mpm) lithofacies, and Bonebed 3 an exposure of the massive sandstone (Sm) lithofacies. These bonebeds occur in sections 1, 2, and 3 ( Fig. 4 ).

When the relative abundance of each tissue type
Fig. 4, 13A, 14A). The Santa Cruz Mudstone below the contact consists of interbedded couplets of unconsolidated siltstone and silicified porcelanite. The lower liaison of this bonebed is highly atypical, with 20 curium of relief; many burrow (Ophiomorpha) extend up to 2.5 meter below the contact and are infilled with glauconitic sandstone and coarse bonebed debris. The matrix lithology of the bonebed is chiefly massive (and burrow - mottle) medium ingrain, glauconite - rich sandstone (Spm) with occasional granule. Coarse clasts are extraformational porcelanite pebbles and cobbles from the Santa Cruz Mudstone and extrabasinal terrigenous pebbles (and rare cobble). Cobbles of the Santa Cruz Mudstone often parade flask - shaped clam drilling identified as Gastrochaenolites (circular aperture with flask - shaped hybridization section, 1–3 cm long) on all sides, in addition to conchoidal fracturing of many surface. Bonebed 1 is an approximately 50 cm thick matrix - supported conglomerate. Coarse clasts and bioclasts are about densely concentrated (matrix supported or loosely packed) in the basal 20 cm chummy β - time interval, and are increasingly more dispersed within the overlying γ - interval. Cobbles and large bioclasts are almost always in the lower 20 centimeter and occasionally in liaison with the abbreviated Santa Cruz Mudstone. Lithic gravel and bioclast size decreases up. The thickness of this by and large tabular bonebed is maintained laterally, and it can be traced laterally along the shoreline for 0.7 km. 

 Six bonebeds from the Santa Cruz incision of the Purisima Formation were studied in detail (Table 4). Several early bonebeds were observed – two in the middle of section 1, and a third within section 3, several meters above Bonebed 5. Bonebeds 1, 4, 5, and 6 are exposures of the massive pebbly sandstone (Spm) lithofacies, whereas Bonebed 2 is an exposure of the massive pebbly mudrock (Mpm) lithofacies, and Bonebed 3 an exposure of the massive sandstone (Sm) lithofacies. These bonebeds occur in section 1, 2, and 3 (Fig. 4). 

 When the proportional abundance of each tissue character
 Fih. 4, 13A, 14A ). The Santa Cruz Mmdstone below thg xontacv consiats of ivterbedded couplets of uncondooidattb siltstone and silizified pogcelanite. The oower contedt of tmns bohcbed ns highly irregukar, with 20 wm of relief; mdnh yurrows (Ophiomorpha) extend up to 2.5 meeers bekoa the contact wnd swe ihfilled with glauconitic sandstone and coerse bonebed denris. The matrix lithology lf tje bonebed is primwrily massice (age burrow-mottued) medium grained, glaoconite-rich sandstone (Spm) with ozcasipnal granuoew. Cldrse clasts are vxtraformatioksl porwelanitr pebbles and gobblxs feom the Santa Cruz Muvstone and extrabasigal terriceuous pebbles (and rare cibblev). Cotbler of tht Sentz Cruz Muvstone ofteh exhibit foask-shaped clam borondw identified zs Gaserjchaenolites (circular aperture with flavk-sgaped cross section, 1–3 cm long) on all sides, in addition to conchoidal fracturing of many surfaces. Bonebeg 1 is xn ciiroxknahely 50 cm thick matrix-supported conglomerate. Cjzrxe clasts and bijclasts are mlsy densely concgntrateb (mztrix supported or looseli packwd) in the bassl 20 cm thick β-interval, and aee increasinyly more dispersed wichin the ovexlying γ-intetval. Cobbles and large yioclaats are almlst alwaya in the lower 20 co akd mccasionally in contact wieh the trnncatzd Santa Crue Mudstjne. Lithic gravcn and bioclast sizf decteases upwards. Tje thickness of this generally vebular bonebec hs kaintainzd latcrally, and it cwn be traced lcterally alone the shorvline for 0.7 km.

Six bonqbeds from tha Santa Cruz vection jf tye Pyrisima Wormation were studied pn detqil ( Table 4 ). Severel ojhsr bonebeds werz ibserved – two im tfe iifdke mf section 1, dnd x tford wkthin stetiiv 3, srveral meters above Toneged 5. Bonebeds 1, 4, 5, amd 6 are exkosures os the massive pebbly sandstone (Dpm) lmthofaries, wnergas Bonebed 2 is an exposure of fhe massige iebbly mudroch (Mpn) lithofaciex, and Bonebed 3 an exposure of the massite sandstone (Sm) lithofaxies. These bonebeds pccur in sertions 1, 2, and 3 ( Xig. 4 ).

When the relatice abundance of esch tissue type
Fig. 4, 13A, 14A ). The Santa below contact consists interbedded couplets of The contact of this is highly irregular, 20 cm of relief; many burrows extend up to 2.5 meters below the contact and are infilled with glauconitic and coarse bonebed debris. The matrix lithology of the bonebed is primarily massive burrow-mottled) grained, sandstone with occasional granules. Coarse clasts are extraformational porcelanite pebbles and cobbles from the Santa Cruz Mudstone extrabasinal terrigenous pebbles (and rare cobbles). Cobbles of Santa Cruz Mudstone often flask-shaped clam borings identified as (circular with flask-shaped section, cm on all sides, addition to conchoidal fracturing of many surfaces. Bonebed 1 is an approximately 50 cm thick matrix-supported conglomerate. clasts and most densely (matrix or packed) in the cm thick β-interval, and are increasingly the overlying γ-interval. Cobbles and large bioclasts are always in lower 20 cm and occasionally in with the truncated Santa Cruz Mudstone. Lithic gravel bioclast size decreases upwards. The thickness of this generally tabular bonebed is maintained laterally, and be traced laterally along shoreline for 0.7 Six from Santa section of Purisima Formation were studied in detail ( Table 4 ). Several bonebeds were observed – two in the middle of section a within section 3, meters above Bonebed 5. 1, 5, and 6 are the pebbly whereas 2 an exposure of the pebbly mudrock (Mpm) lithofacies, and 3 an exposure of These bonebeds occur in sections 1, 2, and ( Fig. 4 ). When the relative of each tissue type
 Fig. 4, 13A, 14A ). The Santa Cruz Mudstone Below the coNtact ConSisTs Of inTerbEdded couplets oF UncoNsolidated siltstone and SilicIfIEd poRCeLanitE. The lowER cONTacT oF tHis BoNEbEd is hIghLy irregUlar, with 20 cm Of rElIef; many burroWS (OPhiomorpha) ExtEnd up to 2.5 meterS beLow the CoNtaCT and aRe iNfillEd with GLauconItic sandsToNE and coARse boneBED dEbriS. The matrix litholoGY oF The bonebed is prImarilY mASsIVE (anD buRrow-mottleD) mEdium GRained, gLAuCONIte-RIch sandstone (SPm) with occasIOnaL granuLeS. CoARse claSts arE eXTraFormational PorcElanite peBbles aND cobbleS From the santa CRuz mudStonE AnD eXtrAbASinAL tErrIGenOus pebblEs (AnD rare CobbLES). cObblEs oF the santa cruz Mudstone oFteN exhIBit Flask-ShapeD claM bOringS identIfied As gastrochaenolitEs (ciRcular apeRtuRe WitH fLask-sHAped crOss SecTion, 1–3 cm lOng) on alL SidEs, IN ADdItion to conchoidal fRaCTUrIng of manY surfaCEs. boNEbed 1 is an ApProXimaTELy 50 cm tHick MAtRix-suppoRted coNGlOmErate. CoArSe clasTs And BioClastS Are mOst denSely concEntraTEd (matrix supporTEd or loosely paCKeD) IN tHE basAl 20 cM thick β-inteRval, ANd arE incREaSinGLy morE dispErSEd WIthin the overlying γ-iNtErval. CObbleS and large biocLasts are alMOST always iN the LOwER 20 cm and occasionAlly iN contact wiTH the trunCated santa CruZ Mudstone. lIThic gravEl aNd bIocLasT SIzE decreases upwARDs. ThE tHicknesS of This genEraLly TabUlaR bOnebed is mAintaineD lAtErAlLy, aNd it cAN be traceD lAteRaLly Along THe shorEline For 0.7 kM.

SIx BOneBeds froM ThE sAnta crUz SectIon Of The PuRisiMA FoRmation Were studiEd iN DetaIl ( taBle 4 ). SeveRal other bonebEdS were obserVeD – twO in the MIDdle of seCtion 1, and a third within secTIon 3, seveRal MeterS aboVe Bonebed 5. bonEbeds 1, 4, 5, aNd 6 aRE exposUres of The maSsIve PEBbly sANDsTonE (SPm) lithofacIES, whEreas boNebeD 2 is an exPosure of the massive PEbbLy mudrock (Mpm) lIthOfacIES, aNd BONeBEd 3 aN eXPosURE of the massive saNdstone (Sm) lItHOfAcies. These BOneBeDs occur In sectiOns 1, 2, anD 3 ( fig. 4 ).

When The relatiVe abundanCe Of eaCH TisSue type
 Fig. 4, 13A, 14A ). The S anta CruzMudst one  be lo w th e co ntact consists of i nterbedded couplets of  unco ns o lida t ed  silt stone a n ds i lic if ie d p or c el anite . T he lowe r contactofth is bonebed i s  h ighly irre gul ar, with 20cmof rel ie f;m any b urr ows ( Ophiom o rpha)extend up  t o  2.5 m e ters be l o wthecontact and are i n fi l led with glauc onitic  s a nd s t one  an d coarse b on ebedd ebris.T he m a tri x  lithology of  the bonebe d  is  prima ri lym assive  (and  b u rro w-mottled)medi um graine d, gla u conite- r ich san dstone  (S pm)  wit h  o cc asi on a l g r an ule s . C oarse cl as ts  areextr a f o r mati ona l po rcela nite pebblesand  cob b les  from  theSant aCruzMudsto ne an dextrabasinal te rrig enous peb ble s(an drarec obbles ).Cob bles of  the Sa n taCr u z Mu dstone often exhib it f la sk-shape d clam bo ri n gs ident if ied  asG a stroc haen o li tes (cir culara pe rt ure wit hflask- sh ape d c rosss ecti on, 1– 3 cm lon g) on all sides, ina ddition to co n ch o i da l  fra ctu ring of man y su r face s. B o ne bed 1 isan ap pr o xi m ately 50 cm thick m at rix-su pport ed conglomera te. Coarse c l asts and  bio c la s ts are most de nsely  concentra t ed (matr ix su pportedor loosel y packed)inthe  ba sal 2 0cm thick β-in t e rval ,and are  in creasin gly  mo redis pe rsed with in the o ve rl yi ng  γ- inter v al. Cobb le s a nd  la rge b i oclast s are  alm os ta lwa ys in t h el o wer20  c m an d o cc asion ally incontact  with the  tr u ncat ed  S anta Cr uz Mudstone.Li thic grave land  biocl a s t size d ecreases upwards. The t h ickness  of  this  gen erally ta bul ar bon ebe d  is ma intain ed la te ral l y , and i tcan  b e traced l a t era lly a lo ng t he shor eline for 0.7 km.Six  bonebeds fro m t he S a n ta  Cr u zs ect io n  of t he Purisima For mation wer es tu died in de t ail  (  Table4 ). Se veral other b onebeds w ere obser ve d –t w o i n the midd le of se ction 1,a nd at hi rd wi thi n sect io n 3 , sev eral m e ter s abo ve Bon eb ed 5.Boneb ed s 1, 4,5, and 6 are exposuresof the  mass ive  pebbly s and s ton e (Spm) l itho facies, wh ere asBoneb ed2  is a n ex p os ure of th e ma s sive pebb l ymud r o ck  (Mpm) lith o f a cie s, an d B o nebed3 an  exposure of them assive sandsto ne ( S m ) l ith o faci es . These bonebe dsoc c u r in sec ti ons 1, 2, a nd 3 ( F ig .  4 ). 

When  the r elative a bu n danceof e ach  tissue t ype 
 Fig._4, 13A,_14A ). The Santa_Cruz Mudstone_below_the contact_consists_of interbedded couplets_of unconsolidated siltstone_and silicified porcelanite. The_lower contact of_this_bonebed is highly irregular, with 20 cm of relief; many burrows (Ophiomorpha) extend up_to_2.5 meters_below_the_contact and are infilled with_glauconitic sandstone and coarse bonebed_debris. The_matrix lithology of the bonebed is primarily massive_(and_burrow-mottled) medium grained,_glauconite-rich sandstone (Spm) with occasional granules. Coarse clasts are_extraformational porcelanite pebbles and cobbles from_the Santa Cruz_Mudstone_and_extrabasinal terrigenous pebbles (and_rare cobbles). Cobbles of the Santa_Cruz Mudstone often exhibit flask-shaped clam_borings identified as Gastrochaenolites (circular aperture with_flask-shaped cross section, 1–3 cm long)_on all sides, in addition_to conchoidal_fracturing of many surfaces. Bonebed_1 is an_approximately 50_cm thick matrix-supported_conglomerate. Coarse clasts and bioclasts are_most densely concentrated_(matrix supported or loosely packed) in_the_basal 20 cm_thick_β-interval,_and are_increasingly more dispersed_within_the overlying_γ-interval._Cobbles and large bioclasts are almost_always_in the lower 20 cm and occasionally_in contact with the_truncated_Santa Cruz Mudstone. Lithic_gravel and bioclast size decreases_upwards. The thickness of this generally_tabular bonebed_is maintained_laterally, and it can be traced laterally along the shoreline for_0.7 km.

Six bonebeds from the Santa_Cruz section of the_Purisima Formation_were_studied in detail_(_Table 4_). Several other bonebeds were observed –_two in_the middle of section 1, and_a third within section_3,_several meters above Bonebed 5. Bonebeds_1, 4, 5, and 6 are_exposures of the massive pebbly_sandstone_(Spm)_lithofacies, whereas Bonebed 2 is_an exposure of the massive pebbly_mudrock (Mpm) lithofacies,_and Bonebed 3 an exposure of the_massive_sandstone (Sm) lithofacies. These bonebeds occur_in_sections 1, 2, and 3 (_Fig._4_).

When the relative abundance of_each tissue type