So there I am minding my business, perusing the pages of The Fossil
Forum when I happen to chance upon a thread about an ammonite the author
says had been gifted to him from somebody who claimed that the extinct
cephalopod came from California. See the thread at The Fossil Forum over
at
https://www.thefossilforum.com/index.php?/topic/135305-real-or-concrete/
.. It is a rather nice robust ammonite, indeed--around a full foot in
diameter.

A thread participant then Googled ammonites in California and came up
with my page pertaining to Union Wash over at
https://inyo.coffeecup.com/site/uw/unionwash.html (Ammonoids At Union
Wash, California),where the lower Triassic Union Wash Formation in the
shadows of Mount Whitney--highest peak in the contiguous United
States--yields beaucoup ceratites type ammonoids (goniatites and
ceratites sutured cephalopods are necessarily called ammonoids--only
those with ammonoites sutures can be correctly called ammonites, and
those kinds lived during the Jurassic and Cretaceous Periods, of course)
that lived roughly 248 million years ago, "only" three to four million
years after the end time Permian extinction event of about 252 million
years ago.

But then another thread contributor pointed out that the mystery
cephalopd in question did not possess ceratitic sutures; it contains an
ammonites-style suture, and so that rightly determines is proper
taxonomic placement: it is thus a more "modern" ammonite of Jurassic to
Cretaceous geologic age. That poster also assigned it to the genus
Lytoceras.

So let's presume that that poster is correct. I have no definitive
evidence to claim otherwise: the suture pattern speaks for itself.
Therefore, one is obliged to inquire Where in California could one find
a Lytoceras cephalopodic ammonite?

Possibilites: Lytoceras has been reported from several localities in
California, in actual fact.

From USGS Bulletin 133 by Timothy William Stanton, published in
1895--The Fauna of the Knoxville Beds:

"Well-preserved specimens nearly all show the crenulated costse
described by Whiteaves in A. crenocostatus, which he afterwards referred
to L. batesi. The peristome is greatly thickened and reflected in this
species. This feature is indicated by the periodic constrictions on the
internal cast, and it is well shown by a fragment of a large specimen
recently collected in the Lower Horsetown beds, near Paskenta, Cal. (See
PI. XIII, figs. 9 and 10.) The whorl from which this fragment came was
nearly 4 inches in diameter, and the whole shell must have exceeded a
foot in> diameter. The shell near the aperture has a thickness of 3
millimeters, which increases suddenly to 5 or 6 millimeters, and this
thickened portion is abruptly reflected, first inward and then outward,
so that a cross section of it has a narrow U-shape. The trumpet-shaped
aperture of Lytoceras immane as described and figured by Neumayr 1 is of
the same type, but somewhat more simple, as the peristome is only
slightly reflected and expanded outward. Locality and position. The
fragment showing part of the aperture is from the Lower Horsetown beds,
about 3 miles north of Paskenta, The other figured specimen is from the
Upper Knoxville beds, on Wilcox's ranch, about 3 miles farther north. It
is not uncommon at this horizon. Fragmentary specimens of the same or a
closely related species have been collected much lower in the Knoxville
beds, on south fork of Elder Creek, associated with Aucella piocMi. It
is most abundant
and best preserved, however, in the Lower Horsetown beds, in Shasta
..and Tehama counties, from the north fork of Cottonwood Creek south-
ward; also at Eiddles, Oreg.; in Queen Charlotte Islands, etc.
Gabb also reports it from two localities in the Chico group, but this
is probably an error in identification, as it has not been found in any
of the later collections from those beds, and there are other forms
there that, when not well preserved, might be mistaken for it.
(National Museum Catalogue, Mesozoic Invertebrate Fossils, 23085
and 23080.)"

From that same publication: "The reported occurrence of
Lytoceras batesi at Benicia and south of Mount Diablo has been cited
as evidence that the Horsetown beds are probably present there, but
Gabb distinctly credits these specimens to the Chico."

Lytoceras batesi also reported from Cow Creek. From Bulletin 133: "Some
of the exposures in the central portion.of the area, as on the
banks of Cow Creek just below the bridge at Kiddles and in the first
low ridge east of the creek, a short distance above the town, are very
fossiliferous, yielding a number of species characteristic of the Horse-
town beds, with some new forms that have not been seen elsewhere."

Lytoceras batesi near Lowerys--from USGS Bulletin 133: Locality and
position. "Two miles north of Lowerys, Tehama County,
Cal., from the upper layers of the Knoxville beds, where it is
associated with Aucella crassicollis, Lytoceras batesi, etc. "The
specimen was insideof a fragment of the last-named species."

Lytoceras saturnale reported from the Paskenta Quadrangle. From USGS
Professional Paper 647-A, 1969: Structural and Stratigraphic
Significance of the Buchia Zones in the Colyear Springs-Paskenta Area
California:

"Mollusks other than Buchia in the Buchia keyser-
lingi zone of the Paskenta quadrangle include the
following :

"Anomia senescens Stanton (USGS Mesozoic loc. 1087)
Niicula gabU Stanton (USGS Mesozoic loc. 1088)
Astartc trapez&ldalis Stanton (USGS Mesozoic loc. 1088)
Twbo? trilineatus Stanton (USGS Mesozoic loc. 1088)
Wiumerosus Stanton (USGS Mesozoic loc. 1088)
Belemnites impresses Gabb (USGS Mesozoic loc. 1088)
Lytoceras saturnale Anderson (USGS Mesozoic loc. 1087)
Crioceratites sp. (USGS Mesozoic loc. 1009, equals 1087)
Thurmanniceras jenkinsi (Anderson) (USGS Mesozoic Iocs.
1088, 1091, M1575, M1578, M1579, M3058, MSOS^, UC
B-5085) stippi (Anderson) (USGS Mesozoic Iocs. 1091, H1580,
M3059, M3084"

Possible occurrence of Lytoceras in Alameda County in the Cretaceous
Horsetown Formation, as well--from an older popular fossil locality page
whose URL I will not provide.

Note: From here on out: All quoted sections to end of this post came
from The Geological Society of America Memoir 71, "Upper Cretaceous Of
The Pacific Coast" by F. M. Anderson, originally published on June 6, 1958,

Lytoceras coalingense found near the upper Cretaceous Moreno Formation,
near the Panoche Hills, western side of the Great Central Valley.

"Immediately north of the Panoche Hills, at locality 28306 (C. A. S .),
Taff, Hanna, and Cross collected a small but diagnostic fauna near the
center containing the following species: Lytoceras ( G audryceras)
coalingense n. sp. Anchura sp. E xiteloceras vancouverense (Gabb) M
acrocallista aff. M . cordata Waring."

Lytoceras kayei reported from: "Various accounts of this species have
been found in the literature of the West Coast. The writer (1902, p.
83) mentioned its occurrence in the Upper Cretaceous near Mount Diablo,
Contra Costa County, but its exact locality and are not known."

Lytoceras alamdense: "An example of this species (C. A. S. Type Coll.)
found at locality 1343 (C. A. S.) near the head of Pleasants’ Valley,
Yolo County."

Lytoceras tenuiliratum: "A well-preserved, but broken specimen of a
lytoceratid species, closely related to the form figured and described
by Yabe, was found by Popenoe and Findley at locality 1347 (С. I. T.)
on Roaring River, Shasta County, above the junction of this stream with
the North fork of Cottonwood Creek."

Lytoceras (Gaudryceras) texanum: "The holotype was found at locality 465
(C. A. S.), Texas Springs, 3 miles east of old Horsetown"

Lytoceras (Gaudryceras) coalingense: "Two incomplete examples were found
12 miles northwest of Coalinga, Fresno County, associated with
Parapachydiscus catarinae Anderson and Hanna, Neokotôceras fresnoense
Anderson, Baculites occidentalis Meek, and many other species."

Lytoceras (Gaudryceras) aureum: "The species is represented by a single
example found by Allan Bennison, locality 29656 (C. A. S.), in coarse
pebbly sandstone along canyon 1 mile south of Ortigalita Creek."

Lytoceras (Gaudryceras) birkhauseri: "The holotype was found by Max
Birkhauser at locality 2361 (C. A. S.), about 2 milesnorthwest of “Oil
City”, or 11 miles northwesterly from Coalinga, Fresno County. The same
species has been recognized by the writer at locality 2362 (C. A. S.),
on Los Gatos Creek, 8 miles northwest of Coalinga."

Lytoceras (Tetragonites) henleyense: "Original example of the present
species, referred by the writer to Stoliczka’s form, was found at
Henley, Siskiyou County."

Lytoceras (Tetragonites) jacksonense: "The original description of this
species was based upon a single example in which the umbilical pit was
not fully exposed, and its suture lines were not clearly shown. The holo
type No. 44 (C. A. S. Type Coll.) was recovered from the ashes of the
San Francisco fire, and other examples were later obtained at its type
locality. A larger and more complete example was later found by the
writer near Little Cow Creek, Shasta County, a few miles east of Frazier
Corners."

On Friday, July 28, 2023 at 5:23:28 PM UTC-4, Inyo wrote:
> So there I am minding my business, perusing the pages of The Fossil
> Forum when I happen to chance upon a thread about an ammonite the author
> says had been gifted to him from somebody who claimed that the extinct
> cephalopod came from California. See the thread at The Fossil Forum over
> at
> https://www.thefossilforum.com/index.php?/topic/135305-real-or-concrete/
> . It is a rather nice robust ammonite, indeed--around a full foot in
> diameter.
>
> A thread participant then Googled ammonites in California and came up
> with my page pertaining to Union Wash over at
> https://inyo.coffeecup.com/site/uw/unionwash.html (Ammonoids At Union
> Wash, California),where the lower Triassic Union Wash Formation in the
> shadows of Mount Whitney--highest peak in the contiguous United
> States--yields beaucoup ceratites type ammonoids (goniatites and
> ceratites sutured cephalopods are necessarily called ammonoids--only
> those with ammonoites sutures can be correctly called ammonites, and
> those kinds lived during the Jurassic and Cretaceous Periods, of course)
> that lived roughly 248 million years ago, "only" three to four million
> years after the end time Permian extinction event of about 252 million
> years ago.
>
> But then another thread contributor pointed out that the mystery
> cephalopd in question did not possess ceratitic sutures; it contains an
> ammonites-style suture, and so that rightly determines is proper
> taxonomic placement: it is thus a more "modern" ammonite of Jurassic to
> Cretaceous geologic age. That poster also assigned it to the genus
> Lytoceras.
>
> So let's presume that that poster is correct. I have no definitive
> evidence to claim otherwise: the suture pattern speaks for itself.
> Therefore, one is obliged to inquire Where in California could one find
> a Lytoceras cephalopodic ammonite?
>
> Possibilites: Lytoceras has been reported from several localities in
> California, in actual fact.
>
> From USGS Bulletin 133 by Timothy William Stanton, published in
> 1895--The Fauna of the Knoxville Beds:
>
> "Well-preserved specimens nearly all show the crenulated costse
> described by Whiteaves in A. crenocostatus, which he afterwards referred
> to L. batesi. The peristome is greatly thickened and reflected in this
> species. This feature is indicated by the periodic constrictions on the
> internal cast, and it is well shown by a fragment of a large specimen
> recently collected in the Lower Horsetown beds, near Paskenta, Cal. (See
> PI. XIII, figs. 9 and 10.) The whorl from which this fragment came was
> nearly 4 inches in diameter, and the whole shell must have exceeded a
> foot in> diameter. The shell near the aperture has a thickness of 3
> millimeters, which increases suddenly to 5 or 6 millimeters, and this
> thickened portion is abruptly reflected, first inward and then outward,
> so that a cross section of it has a narrow U-shape. The trumpet-shaped
> aperture of Lytoceras immane as described and figured by Neumayr 1 is of
> the same type, but somewhat more simple, as the peristome is only
> slightly reflected and expanded outward. Locality and position. The
> fragment showing part of the aperture is from the Lower Horsetown beds,
> about 3 miles north of Paskenta, The other figured specimen is from the
> Upper Knoxville beds, on Wilcox's ranch, about 3 miles farther north. It
> is not uncommon at this horizon. Fragmentary specimens of the same or a
> closely related species have been collected much lower in the Knoxville
> beds, on south fork of Elder Creek, associated with Aucella piocMi. It
> is most abundant
> and best preserved, however, in the Lower Horsetown beds, in Shasta
> .and Tehama counties, from the north fork of Cottonwood Creek south-
> ward; also at Eiddles, Oreg.; in Queen Charlotte Islands, etc.
> Gabb also reports it from two localities in the Chico group, but this
> is probably an error in identification, as it has not been found in any
> of the later collections from those beds, and there are other forms
> there that, when not well preserved, might be mistaken for it.
> (National Museum Catalogue, Mesozoic Invertebrate Fossils, 23085
> and 23080.)"
>
> From that same publication: "The reported occurrence of
> Lytoceras batesi at Benicia and south of Mount Diablo has been cited
> as evidence that the Horsetown beds are probably present there, but
> Gabb distinctly credits these specimens to the Chico."
>
> Lytoceras batesi also reported from Cow Creek. From Bulletin 133: "Some
> of the exposures in the central portion.of the area, as on the
> banks of Cow Creek just below the bridge at Kiddles and in the first
> low ridge east of the creek, a short distance above the town, are very
> fossiliferous, yielding a number of species characteristic of the Horse-
> town beds, with some new forms that have not been seen elsewhere."
>
> Lytoceras batesi near Lowerys--from USGS Bulletin 133: Locality and
> position. "Two miles north of Lowerys, Tehama County,
> Cal., from the upper layers of the Knoxville beds, where it is
> associated with Aucella crassicollis, Lytoceras batesi, etc. "The
> specimen was insideof a fragment of the last-named species."
>
> Lytoceras saturnale reported from the Paskenta Quadrangle. From USGS
> Professional Paper 647-A, 1969: Structural and Stratigraphic
> Significance of the Buchia Zones in the Colyear Springs-Paskenta Area
> California:
>
> "Mollusks other than Buchia in the Buchia keyser-
> lingi zone of the Paskenta quadrangle include the
> following :
>
> "Anomia senescens Stanton (USGS Mesozoic loc. 1087)
> Niicula gabU Stanton (USGS Mesozoic loc. 1088)
> Astartc trapez&ldalis Stanton (USGS Mesozoic loc. 1088)
> Twbo? trilineatus Stanton (USGS Mesozoic loc. 1088)
> Wiumerosus Stanton (USGS Mesozoic loc. 1088)
> Belemnites impresses Gabb (USGS Mesozoic loc. 1088)
> Lytoceras saturnale Anderson (USGS Mesozoic loc. 1087)
> Crioceratites sp. (USGS Mesozoic loc. 1009, equals 1087)
> Thurmanniceras jenkinsi (Anderson) (USGS Mesozoic Iocs.
> 1088, 1091, M1575, M1578, M1579, M3058, MSOS^, UC
> B-5085) stippi (Anderson) (USGS Mesozoic Iocs. 1091, H1580,
> M3059, M3084"
>
> Possible occurrence of Lytoceras in Alameda County in the Cretaceous
> Horsetown Formation, as well--from an older popular fossil locality page
> whose URL I will not provide.
>
> Note: From here on out: All quoted sections to end of this post came
> from The Geological Society of America Memoir 71, "Upper Cretaceous Of
> The Pacific Coast" by F. M. Anderson, originally published on June 6, 1958,
>
> Lytoceras coalingense found near the upper Cretaceous Moreno Formation,
> near the Panoche Hills, western side of the Great Central Valley.
>
> "Immediately north of the Panoche Hills, at locality 28306 (C. A. S .),
> Taff, Hanna, and Cross collected a small but diagnostic fauna near the
> center containing the following species: Lytoceras ( G audryceras)
> coalingense n. sp. Anchura sp. E xiteloceras vancouverense (Gabb) M
> acrocallista aff. M . cordata Waring."
>
> Lytoceras kayei reported from: "Various accounts of this species have
> been found in the literature of the West Coast. The writer (1902, p.
> 83) mentioned its occurrence in the Upper Cretaceous near Mount Diablo,
> Contra Costa County, but its exact locality and are not known."
>
> Lytoceras alamdense: "An example of this species (C. A. S. Type Coll.)
> found at locality 1343 (C. A. S.) near the head of Pleasants’ Valley,
> Yolo County."
>
> Lytoceras tenuiliratum: "A well-preserved, but broken specimen of a
> lytoceratid species, closely related to the form figured and described
> by Yabe, was found by Popenoe and Findley at locality 1347 (С. I. T.)
> on Roaring River, Shasta County, above the junction of this stream with
> the North fork of Cottonwood Creek."
>
> Lytoceras (Gaudryceras) texanum: "The holotype was found at locality 465
> (C. A. S.), Texas Springs, 3 miles east of old Horsetown"
>
> Lytoceras (Gaudryceras) coalingense: "Two incomplete examples were found
> 12 miles northwest of Coalinga, Fresno County, associated with
> Parapachydiscus catarinae Anderson and Hanna, Neokotôceras fresnoense
> Anderson, Baculites occidentalis Meek, and many other species."
>
> Lytoceras (Gaudryceras) aureum: "The species is represented by a single
> example found by Allan Bennison, locality 29656 (C. A. S.), in coarse
> pebbly sandstone along canyon 1 mile south of Ortigalita Creek."
>
> Lytoceras (Gaudryceras) birkhauseri: "The holotype was found by Max
> Birkhauser at locality 2361 (C. A. S.), about 2 milesnorthwest of “Oil
> City”, or 11 miles northwesterly from Coalinga, Fresno County. The same
> species has been recognized by the writer at locality 2362 (C. A. S.),
> on Los Gatos Creek, 8 miles northwest of Coalinga."
>
> Lytoceras (Tetragonites) henleyense: "Original example of the present
> species, referred by the writer to Stoliczka’s form, was found at
> Henley, Siskiyou County."
>
> Lytoceras (Tetragonites) jacksonense: "The original description of this
> species was based upon a single example in which the umbilical pit was
> not fully exposed, and its suture lines were not clearly shown. The holo
> type No. 44 (C. A. S. Type Coll.) was recovered from the ashes of the
> San Francisco fire, and other examples were later obtained at its type
> locality. A larger and more complete example was later found by the
> writer near Little Cow Creek, Shasta County, a few miles east of Frazier
> Corners."
>
> Lytoceras (Tetragonites) kernense: "Three examples of this species were
> found by G. D. Hanna at locality 1552 (C. A. S.) on the south border of
> the Antelope Valley, northern Kern County."
>
> Lytoceras (Tetragonites) epigonum: "Numerous examples of this species,
> two hypotypes of which are figured here (PI. 65, figs. 4, 5), and of
> closely related forms have been found by С. C. Church and by the writer,
> associated with Parapachydiscus catarinae Anderson and Hanna and with
> many other species at locality 2362 (C. A. S.), on Los Gatos Creek.
> Others have been collected by Church on the north slope of Joaquin
> Ridge, 11 miles north of Coalinga, Fresno County." Note: I actually have
> two specimens of Lytoceras epigonum figured at my page Dinosaur- Age
> Plants At Del Puerto Canyon, California over at
> https://inyo4.coffeecup.com/morenofossils/morenofossils.html .
>
> Note--there are several additional examples of genus Lytoceras ammonotes
> reported from California in Geological Society of America Memoir 71 by
> F. M. Anderson, for those interested in seeking out the citations.