Upper Cretaceous Ammonites of California Part III
1960; Kyushu University; Volume: Special vol. 2; Linguagem: Inglês
10.5109/1546813
ISSN0023-6179
Autores Tópico(s)Paleontology and Stratigraphy of Fossils
ResumoReliable records of localities are indispensable for paleontologic as well as stra七igraphic studies of ammonites． Aconsiderable number of papers have hitherto been published in which local stratigraphy is described． Although specific names of ammonites may not have been thoroughly listed in these previous papers， the stratigraphic subdivisions established in them can be referred to． Yet I think that probably more than ten years persistent field work will be needed for satisfactory study of七he Upper Cretaceous ammonites of California． Since the period of my stay in California was limited， I couId not， of course， ful創l this requirement． But， owing to kind help of the professors and many other friends， I visited several places to examine stra七igraphic sections and have got some new acquisition． The descriptive notes of local stratigraphy in this chapter depend principally on already published records， but may include some new information as well as my own views． I will record the names of the kind friends who have allowed me to describe in this paper new information which they supplied me． Regarding the stratigraphy of the Redding area， Shasta County and the Santa Ana Mountains I depend very much on Dr． W．P． PopENoE s published and also unpublished work． Therefore joint au七horship is taken for Notes on Stratigraphy of these two areas：articles(2)and(9) in the following descrip七ion． 1． Hornbmok・Yreka area， Siskiyou County， northern California and Jackson County， southwest Oregon Patches of the Upper Cretaceous outcrops are distributed，in a belt roughly running nor七hwest from the Hornbrook-Yreka area ill northern California， along the valley of Bear Creek in southwest Oregon． This general area covers several ＊Received， October 20，1959． Continued from Part II(」已θ物．施c． S￠τ．，陶％8ん％σ励〃．， 8θγ．D， Gθol．， Special Vol．1， pp．1-172， text-figs．1-80；pls．1-41， November 1959)． ＊＊Department of Geology， University of California， Los Angeles． T．MATSUMOTO ammonite localities which have been well known since the date of GABB(1864， 1869)and ANDERsoN(1902)． They are， for ins七ance， Forty-nine Mine， near Phoenix， Oregon (CAS．445， UC． A-169)， SMITH ranch ［＝FITcH ranch］， 2．5miles southwest of Phoenix， Oregon(CAS．445A， UC． A-170)， Dark Hollow， on old Pioneer road，4miles southwest of Phoenix， Oregon (CAS．444， CAS． 455)， Rocky Gulch， sou七hwest of Hornbrook， Siskiyou County， California (CAS． 444A)， and 0．5 mile south of Hornbrook， Siskiyou County， California，，(CAS． 444B)． These place names do not necessarily indicate a precise locality for a restricted thickness of the stratigraphic sequence， but may include， as in the 6rst and the secolld examples， rocks of a wide stratigraphic range． The only reliable stratigraphic description founded on careful丘eld work is that of PEcK，1肌AY， and PoPENoE(1956)． They have proposed the name of Hoγηbγoo〃∫oγ仇α励ηfor the Upper Cre七aceous beds near Henley and Hornbrook， subdividing them into Members I-VI． Fossils do no七〇ccur uniformly throughout，1)ut are restricted to certain particular parts． In the total thickness of 815(±15)meters［2673(±50)feet］along the measured section， Units 4 and 50f Member I， Unit 80f Member II， Unit 140f Member V， and Unit 15 0f Member VI are fossiliferous． According to the authors， the 6rs七七hree among these 6ve units contain Sμbpγioγzo￠〃61τL8 sp．， ColZε9％o？τi￠θγα8 (？) sp．， and o七her Turonian species， while the last two contain 1レfθ毒仰Zα6θ励τcθγα8 pα6俵の襯 (SMITH)，D￠s伽P吻硫θ8 sp．，1D卿α6吻跳6μ8 cf． PθγplZcα仇8(WHITEAvEs)［＝E． んαγα肋i(JIMBo)］， and o七her species of Campanian aspec七． The specimens at my disposal from older collections from this area can be sorted into two groups which approximately correspond to those given above． The species from CAS． 444，for instance， show the Campanian assemblage， while those from CAS．444A show the Upper Turonian one(see the speci丘c names of my identi6cation in the list of localities)． The same statement can be applied to specimens of relatively recent coUec七ions． The localities SOC． K-234， CIT．1042， and CIT．1044 are best referable to Member I， as judged from M． V． KIRK，s and W． P． PopENoE s infor-mation． From them came Sμbpγτ侃o￠び伽s％ep飢物￠(GEINITz)or S． cf．η￠p仇旭， that indicates the Upper Turonian． In connection with this fact， the record of Collぜ9ηo痂6θγα8(？)sp． in Member II above Sμ伽がoηocyolμ8 sp・of Member I in the list of PEcK￠渉α1．(1956)l is rather unusual， but I have not inspected the ac七ual specimens of七heir Coll《gwo旭c￠γα8(？)sp． I would suggest七hat this might be 8μ吻γio％o￠〃￠Zμ8 bγαηηθ冗(ANDERsoN)． From the locality SOC． K-235， which is probably referred to the upPer par七〇f Member V， KIRK obtained the ammonites of UpPer Campanian aspect， AηαPα6吻砺86μ8 dθ￠6αηηθη8is (STo-LlczKA)， Pαcんび(況scμs sp．， and MeZ仰1αce励Zceγαs pαc頒cτL働 (SMITH)・ IMLAY showed me the specimens from USGS． Mes． loc．25218， which belongs to Unit 14 0f Member V of七he Hornbrook formation (see PEcKθεα1．，1956， p．1980)． Ihave identi6ed them to Dθ8伽op吻IZZ ‡θ8∂⑳ん〃IZo掘θ8(FoRBEs)， Pαo吻砺80％8 cf． s％bc・卿γ￠ssμs MATsuMoTo， Mθ ‡αplαce襯cθγαs pαc輌μ働(SMITH)， Gαμd吻一 ￠θγα8sp． and欠θかαgo励εθ8(8α9んα1甑亡θ8)sp． The assemblage suggests the higher part of the Campanian． n m ．
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