Texas Inoceramus clam

[DPS Ammonite]

Here's a great picture of several large Inoceramus clams in the Cretaceous Austin Chalk along White Rock (aptly named) Creek in Plano Texas. Any idea what species?

[tmaier]

Very cool!

I usually bring paper lunch bags for collecting fossils. Do you have some really large lunch bags?

[Monica]

Hi DPS Ammonite!

Those clam fossils are HUGE! It's crazy to think that something so big has been lying around for so long without anyone noticing it until you came along! The fossils that I've collected so far that I thought were pretty big are tiny by comparison! Enjoy your cool find!

Monica

[tmaier]

It's crazy to think that something so big has been lying around for so long without anyone noticing it until you came along!

Those are so large that people like me would normally walk right past it, thinking it was a geological feature.

I'm looking for specimens that fit in my little lunch bags.

[fifbrindacier]

Those are so large that people like me would normally walk right past it, thinking it was a geological feature.

I'm looking for specimens that fit in my little lunch bags.

I think you cannot eat them, your teeth and your digestive tract won't feel well.

Hi DPS Ammonite!

Those clam fossils are HUGE! It's crazy to think that something so big has been lying around for so long without anyone noticing it until you came along! The fossils that I've collected so far that I thought were pretty big are tiny by comparison! Enjoy your cool find!

Monica

In the Museum of Amsterdam, there is an inoceramus that makes 1m80cm. It makes about 5,63 feet.

Edited July 29, 2016 by fifbrindacier

[PFOOLEY]

Very cool. I would guess Inoceramus undulato-plicatus.

STRATIGRAPHIG RELATIONS OF THE AUSTIN, TAYLOR, AND EQUIVALENT FORMATIONS IN TEXAS

[CraigHyatt]

Those are so large that people like me would normally walk right past it, thinking it was a geological feature.

I'm looking for specimens that fit in my little lunch bags.

That'd be a whole lotta chowda theyah! ;-)

[RJB]

Very cool.

RB

[abyssunder]

" Stephenson (1937, p.138) notes that : " In Dallas County the Inoceramus undulatoplicatus Zone is well exposed just below the dam at White Rock Lake, at the northeastern outskirts of Dallas, and the overlying Gryphaea wratheri Zone may be seen in a cut ofn Gaston Avenue near the intersection of West Shore Drive, less then a mile west of the dam " (...)
Young's (1963, p. 23) megafossil data for the type Austin Chalk indicate that the Inoceramus undulatoplicatus Zone is early Santonian in age and is correlative in part with the his Texanites strangeri densicostus Zone. The planktonic foraminiferal evidence strongly supports Young's early Santonian dating of the I. undulatoplicatus Zone. " - Upper Cretaceous Stratigraphy of the Western Gulf Coast Area of Mexico, Texas and Arkansas - Emile A. Pessagno, Jr., 1969

" Inoceramus undulatoplicatus Romer, 1852
PI. 81, figs. 1-3; pi. 82, figs.1-4

Remarks.— Many of Romer's (1852) illustrations leave much to be desired (e.g. compare his pl. 3, figs, la-d of the holotype of Texanites texanus with the illustration of the holotype in this work). As I interpret this species there is considerable variation, but not sufficient to include the small individuals illustrated by Whiteaves (1879, pi. 20, figs. 2, 2a) ;in these individuals the plications are nearly paired, and the Texas examples of Romer's species show no pairing of plications. Inaddition the Whiteaves specimens are not large enough to show the strong concentric undulations.
The greatest variation, in my interpretation, is in the growth stage at which the strong marginal undulations appear. UT-30691 (pi. 81, figs. 2, 3) shows such large
undulations at a somewhat younger stage than does UT-30719 (pi. 82, figs. 1-4), which is a larger specimen with the periphery broken off. Adkins (1933) referred
those forms typified by pi. 82, figs. 1-4, to I. digitatus Sowerby.

Locality and horizons. - Inoceramus undulatoplicatus Romer is from the upper part of formation B (=middle Austin chalk, auctorum, Central Texas) in Central Texas, and is particularly abundant near Walburg, Williamson County. Although it ranges through the zones of Texanites stangeri densicostus (Spath) and Texanites texanus texanus (Romer) , it is particularly abundant in the chalky beds just below the zone of T. texanus texanus. I have no ammonites from the Big Bend locality, but Moon (1953) collected late lower Santonian ammonites from his Inoceramus undulatoplicatus
beds. In Central Texas Inoceramus undulatoplicatus occurs with Texanites texanus texanus (Romer), and T.stangeri densicostus (Spath). " - Upper Cretaceous Ammonites from the Gulf Coast of the United States - Keith Young, 1963

For me, the specimens in question don't look like Inoceramus undulatoplicatus = Cladoceramus undulatoplicatus (ROEMER); WALASZCZYK & COBBAN, p. 308, figs 39.1-3, 40.4 (with synonymy). I think they are other species. Maybe An integrated study (inoceramid bivalves, ammonites, calcareous nannofossils, planktonic foraminifera, stable carbon isotopes) of the Ten Mile Creek section, Lancaster, Dallas County, north Texas, a candidate Global boundary Stratotype Section and Point for the base of the Santonian Stage - A.S. GALE & al. , 2007 could help a little. Here described inoceramid genera : Magadiceramus, Cordiceramus, Platyceramus, Cladoceramus.

Edited July 29, 2016 by abyssunder

[CraigHyatt]

Here's a great picture of several large Inoceramus clams in the Cretaceous Austin Chalk along White Rock (aptly named) Creek in Plano Texas. Any idea what species?

I appreciate the photo. I have a feeling I've seen these and not recognized them. In fact, that's my homework assignment. I'm heading out to the spot now. ;-)

[tmaier]

That'd be a whole lotta chowda theyah! ;-)

Grilled...

With melted butter...

[Ridgehiker]

Wow.

'Dinoceramus'

[doushantuo]

https://upload.wikimedia.org/wikipedia/commons/e/ef/Inoceramus_steenstrup,_world's_largest_fossil_mollusk.jpg

[DPS Ammonite]

Thank you for your help everybody. I think that I need to do additional research to ID the inoceramids. They probably are not Inoceramus undulatoplicatus = Cladoceramus undulatoplicatus since they lack the radial plications.

(Note... I edited this post which originally said that I thought that the fossils were Inoceramus undulatoplicatus.)

THE TRUE STRATAGRIFIC LOCATIONS OF INOCERAMUS, (CLADOCERAMUS), UNDULATOPLICATUS IN THE BIG BEND AREA OF TEXAS
Author: Barnes, Kenneth R.

http://bigbendpaleogeojournal.homestead.com/THE_TRUE_STRATAGRIFIC_LOCATIONS_OF_INOCERAMUS.pdf

I wonder too how tasty these clams might have been. I have heard that clams that live where the is little oxygen (Inoceramus undulatoplicatus probably lived in an area with low oxygen levels) often have a sulphurous smell and taste.

Here is photo of a larger one in the Austin Chalk that I uncovered in Plano, Texas that is about 3 to 3.75 feet across based on hammer length of 13.5 inches.

Edited July 29, 2016 by DPS Ammonite

[abyssunder]

Maybe I'm wrong and I don't want to disagree with anyone of you, but in all the pictures of Cladoceramus undulatoplicatus, posted (or linked ) in this interesting thread, is vissible that the "radial ribs" (not the concentric ones) of the ornamentation are present, while in all of the specimens in question they are not there, no matter if these specimens are internal molds without shells or with partially preserved shell material. That was the reason why I questioned this species. Just another sample from A.S. GALE & al. , 2007 , to see what I'm referring to (somehow to say, they have the Cretaceous oyster Exogyra, or the plicatulidae Plicatula character in their ornamentation) :

[vonfatman]

Those are some serious bi-valves!!

A little rock saw work, a little shaping...you would have the best looking stepping stones in Berkley.

Bob

Edited July 29, 2016 by vonfatman

[BobWill]

Local geologist Tom Dill gave a brief talk on these clams at the June meeting of the Dallas paleontological Society. The general consensus he had gathered from others was that these giants could use some additional research to clarify some of the disparities in classification that abyssunder has brought up. I've been finding some very large inoceramus in the Duck creek of Cooke County Texas but not as large as the one in Amsterdam!

[DPS Ammonite]

Abyssunder, thank you for pointing out the obvious. After looking at my photos and the references, you are right, mine are not Inoceramus undulatoplicatus. What I thought were radial folds only occur in isolated parts of the shell and probably are distortions created during the fossilization process. Inoceramus (Platyceramus) platinus might be a candidate. Any other suggestions?

See this reference for more photos: http://www.kgs.ku.edu/Publications/Bulletins/225/12_plates.html

Edited July 29, 2016 by DPS Ammonite

[DPS Ammonite]

Local geologist Tom Dill gave a brief talk on these clams at the June meeting of the Dallas paleontological Society. The general consensus he had gathered from others was that these giants could use some additional research to clarify some of the disparities in classification that abyssunder has brought up. I've been finding some very large inoceramus in the Duck creek of Cooke County Texas but not as large as the one in Amsterdam!

Bob, how large were the Inoceramus from the Duck Creek? I remember finding some about 6 inches across near the Lake Texoma Dam.

Edited July 29, 2016 by DPS Ammonite

[abyssunder]

I'm not an expert on this, but that was also my though, Platyceramus. Thank you for looking at again, DPS Ammonite.
I agree for an additional research, Bob. Thank you for your intervention in the topic.

[JohnBrewer]

Dolls house hammer I recon....

[Wrangellian]

A number of the Inoceramids, specifically the smaller ones with the more complex cross-ribbing, have been split off into the Sphenoceramids.... that might eliminate some of the confusion. Older references will have them all as 'Inoceramus'.

[BobWill]

Bob, how large were the Inoceramus from the Duck Creek? I remember finding some about 6 inches across near the Lake Texoma Dam.

Yes John weren't we seeing some this size at Caney Creek too? I saw some bigger in Spring Creek near Valley View but I brought this one home because it had both valves. I believe both sites are Duck Creek Formation.

[DPS Ammonite]

Yes John weren't we seeing some this size at Caney Creek too? I saw some bigger in Spring Creek near Valley View but I brought this one home because it had both valves. I believe both sites are Duck Creek Formation.

inocera.jpg

I remember similar ones at Caney Creek. Are the Duck Creek Fm. Inoceramus like yours: Inoceramus comancheanus?

[DPS Ammonite]

Here is a reference to Inoceramus (Platyceramus) platinus in Colorado that look similar to my photos and occur in a similar environment: chalk with pyrite (indicates low oxygen conditions).

Paleoecology of Giant Inoceramidae (Platyceramus) on a Santonian (Cretaceous) Seafloor in Colorado
Erle G. Kauffman, Peter J. Harries, Christian Meyer, Tomas Villamil, Claudia Arango and Glenn Jaecks
Journal of Paleontology
Vol. 81, No. 1 (Jan., 2007), pp. 64-81

I note that Inoceramus (Platyceramus) platinus occurs south of Plano. See: http://www.springcreekforest.org/Fossils.htm