Possible Lunulites From The Castle Hayne?

[Wendell Ricketts]

Hello all. I'm writing for help w/the id of the specimen pictured, collected in the Castle Hayne Fm. of No. Carolina. A knowledgeable friend has suggested Lunulites sp., which is more than plausible. An Greeley's "Basally Uncalcified Zoaria of Lunulitiform Bryozoa," (J.Paleo, Vol. 43, No. 2 , Mar., 1969, pp. 252-256), contains an intriguing illo (Plate 34, Nos. 1-2, p. 252), which resembles my specimens - but Greeley's Lunulites are magnified 14x, in keeping w/my limited experience with the species.

I've collected Lunulites, that is (or Lunulites-like bryozoans), both in the Texas Eocene and the Italian Pliocene, and the specimens are always quite small. The No. Carolina specimens are much larger, and the pictured specimen is the largest of the eight or so I collected. They are quite clearly molds. Can anyone shed any light?

Many thanks,

Wendell

[grandpa]

Wendell,

In his book Cretaceous and Paleogene Fossils of North Carolina (North Carolina Fossil Club, 1995, p.47), Richard Chandler shows this and 3 other similar species and ID's them as Lunulites sp. I have found examples of all 4 types (species?) pictured in Chandler's book throughout the Castle Haynes fm. They have ranged in size from penny dia. to quarter dia. The one you pictured is one of the more common types that I have found. Based on Chandler and on your sources, I'd say you do have a Lunulites sp. bryozoan from the Castle Haynes.

[jkfoam]

Wendell,

Bryozoans generally take microscopic examination of the zoarium/zooecium and particularly the aperture or peristome to get identification. That said, your specimen resembles the large bryozoan, Smittina collum Cantu snd Bassler, 1920, from the Castle Hayne fm. Not having the references readily at hand I can't really argue against a Lunnulites sp. identification either.

JKFoam

[grandpa]

In The Coastal Plain of North Carolina by Clark & Miller (p.187) "Miss. Julia A. Garner has determined the following bryozoans, brachiopods and mollusks (obtained from the city rock quarry at Williamington):

Bryozoa:

Lunulites distans Lonsdale"

http://books.google.com/books?id=xGwNAAAAY...zoa&f=false

In Free-Lying Domal Bryozoan Colonies of the Castle Haynes Limestone, Eastern North Carolina by Frank K. McKinney, he states "Dome-shaped cheilostome bryozoan colonies, approximately 2 cm in diameter, are common among the abundant and diverse bryozoans in offshore deposits of the upper Castle Hayne Formation, southeastern North Carolina. The domes originate in three very different ways: individual colonies of Smittina collum Canu and Bassler; individual colonies of ?Osthimosia sp.; or diverse multispecies overgrowths. . . http://gsa.confex.com/gsa/2001SE/finalprog...stract_3865.htm

See also: Palaeoecology of free−lying domal bryozoan coloniesfrom the Upper Eocene of southeastern USA

FRANK K.MCKINNEY and PAUL D.TAYLOR

http://www.app.pan.pl/archive/published/app48/app48-447.pdf

for a more detailed description with plates for ID.

When you figure out what you have, let me know 'cause I have a bunch too.

I think it's like JK said, "microscopic exam".

[Wendell Ricketts]

Hello and many thanks! Unfortunately, because these are molds, there's nothing to thin-section, even if I had the capability to do so. I also collected specimens of what McKinney and Taylor call Parasimittina colum, which are markedly different from the "mystery fossil," both grossly and under the stereo mike. They're also the right size (c. 2cm) and smaller than the ?Lunulites specimens, generally. I'm going to keep looking (and we'll see what else others come up with here), but ?Lunulites doesn't strike me as a bad idea at all at this point!

W.

In The Coastal Plain of North Carolina by Clark & Miller (p.187) "Miss. Julia A. Garner has determined the following bryozoans, brachiopods and mollusks (obtained from the city rock quarry at Williamington):

Bryozoa:

Lunulites distans Lonsdale"

http://books.google.com/books?id=xGwNAAAAY...zoa&f=false

When you figure out what you have, let me know 'cause I have a bunch too.

I think it's like JK said, "microscopic exam".

[Wendell Ricketts]

Thanks for your help! A helpful study is McKinney and Taylor, which you can find online: http://www.app.pan.pl/archive/published/app48/app48-447.pdf .

It shows Parasimittina collum, which grossly matches three or four of my specimens, but which is rather different from the mystery fossil. The latter may well be large Lunulites (if Parasimittina and Lunulites are the only two likely choices).

It's also true of my specimens, as M&T note, that P. collum is "fouled" with multiple species of other bryozoa, as are echinoids and other specimens from the quarry.

All best,

W.

Wendell,

Bryozoans generally take microscopic examination of the zoarium/zooecium and particularly the aperture or peristome to get identification. That said, your specimen resembles the large bryozoan, Smittina collum Cantu snd Bassler, 1920, from the Castle Hayne fm. Not having the references readily at hand I can't really argue against a Lunnulites sp. identification either.