CG-0060, S. carbonaria. An exceptional specimen.
CG-0060, Shansiella carbonaria

The Paleozoic gastropod (snail) Shansiella carbonaria (Norwood & Pratten, 1855) is a common find at a Pine Creek limestone locality I collect from Armstrong County, Pennsylvania. I also recover specimens from the Brush Creek limestone. Examples of S. carbonaria are easy to come by (especially at the Pine Creek locality), and I find each to be unique and visually pleasing to examine. Norwood & Pratten first described this medium-sized snail species more than 160 years ago as Pleurotomaria carbonaria. Percy Raymond, the Carnegie Museum’s first Assistant Curator of Invertebrate Paleontology reported it locally from the Brush Creek and Ames Limestone (Raymond, 1909). Yin created the genus Shansiella in 1932. Years later Knight, Batten, and others reassigned Pleurotomaria carbonaria to Yin’s new genus, Shansiella.

Roger Batten erected the family Portlockiellidae in 1956 and placed Portlockiella kentuckyensis as the type species. He did so in a short article, so as to allow publication of this family in the upcoming Treatise of Invertebrate Paleontology. Only two years later he published a rather large volume on Permian gastropods from the southern United States. He created two new species of Shansiella that have since been to the genus Permoconcha. Batten also performed detailed work in the 1970s using images generated by a scanning electron microscope. His work showcased the crystalized aragonite on S. carbonaria specimens collected from the Eastern United States.

In more modern times, Richard Hoare and others reported on the distribution of several Pennsylvanian fossil gastropods throughout the marine units in the Appalachian Basin. Specimens of Shansiella carbonaria are reported to be recovered from ten of fourteen distinct Pennsylvanian-aged marine zones (Hoare et al, 1997). The species is often found in Upper Carboniferous publications such as Fossils of North Texas, and Fossils of Ohio.

Stratigraphic occurance of S. carbonaria through the Pennsylvanian of the Appalachian Basin - 1997 Hoare et al.
The yellow zones on the top of the graphic indicate confirmed recovery of S. carbonaria through different marine zones in the Appalachian basin. It’s highly likely that it can be found in both the Upper Mercer and Dorr Run zones, but up to now, it is not confirmed. Several zones have different names in Western Pennsylvania. For example, the Portersville is known as the Woods Run and Carnahan marine zones locally. Some modern variances apply, such as the Carnahan zone is actually neighboring shale from the Woods Run zone (Harper, 2016).

The Differences Between the Brush and Pine Creek Marine Zones

Both the Brush Creek limestone and the Pine Creek limestone are situated in the Glenshaw Formation. The Glenshaw and Casselman Formations make up the larger Conemaugh Group. The Ames Limestone divides the two formations and is the youngest reported horizon for S. carbonaria in the Appalachian Basin (Hoare et al., 1997).

The Pine Creek locality has yielded the majority of S. carbonaria specimens that I have recovered. It also contains an abundance of gastropods within the available fossil fauna. Bivalves, cephalopods, and numerous horn corals make up the other major faunas found in the fossiliferous rocks at the locality. Smaller quantities of crinoid columns, brachiopods, and Petalodus teeth have also been recovered. The limestone and adjacent rock are very fissile. The gastropod specimens recovered tend to have nearly all of the shell intact.

In comparison, the Brush Creek limestone is a non-fissile rock. Gastropods are less common in the Parks Township locale. The major available fauna includes brachiopods, cephalopods, and bivalves. The bivalve genus Avliculpinna? is very abundant, which could help determine the paleoecology of the area. Recovered gastropods have their shells strongly adhered to rock, a common problem throughout the Appalachian Basin (Hoare et al., 1997).

Turbo insectus, likely an example of S. carbonaria.
Figure 1—Turbo insectus, Conrad, 1835

In 1835, Conrad Describes Turbo insectus

In 1832. Edward Miller, an assistant railway engineer, started work on a multi-year project to build the Allegheny Portage Railroad. The goal was to connect the two major canals in Pennsylvania by building inclined railway planes that pulled cars up and over the Allegheny Mountains. The canals ran along the Juniata and Conemaugh rivers and were used for the transportation of materials and people. The Conemaugh Group, which contains the Glenshaw Formation, is named from outcrops along the Conemaugh River.

During construction, Miller would spend his idle time examining exposed rock outcrops. He later created a geological report that he presented to the Geological Society of Pennsylvania. In the report, he wrote that “great numbers of shells were loosed and fell out” during the removal of large rocks during excavation (Miller 1835).

Timothy Abbott Conrad described five marine fossils from specimens Miller had sent to the society. Turbo insectus was one of the five. However, Conrad’s mention of this species would be the last. The species has not been reported on again since Conrad’s original writing.

While impossible to confirm in modern times, Percy in 1909, Girty in 1937, Sturgeon in 1946, and Harper in 2016 considered Conrad’s specimen of Turbo insectus to likely be the modern Shansiella carbonaria. The shell features a similar profile and corded ornamentation. It came from a locality that correlates with the Brush Creek marine zone. The biggest thing that casts doubt from a visual inspection is the general shape. Being a simple illustration, it’s possible that this may not represent an exact morphological depiction of the original specimen.

Conrad’s Description

The original description was short and hard to read by today’s standards. Conrad uses “whirls” instead of “whorls”. The description is a single sentence.

TUBRO, Lam.
T. insectus. Pl. 12, fig 4. Shell turbinate, ventricose, with prominent coarse revolving striae; whirls convex, flattened above; aperture orbicular, about half the length of the shell.

The specimen reported on has not been found in any paleontological collection. This makes Turbo insectus impossible to validly synonymize with Shansiella carbonaria. Therefore, Norwood & Pratten are the original authors of the species. Sturgeon had mentioned a possible way to synonymize the two, but it would require recovery of S. carbonaria from the type locality and proof that T. insectus is not available as Conrad had illustrated the specimen.

The fossil description itself is, in fact, an important historical event. It was part of the first confirmed descriptions of Pennsylvanian marine invertebrates from North America (Harper, 2016). Conrad’s 1835 paper was the first published North American report of Pennsylvanian marine fossils.

Norwood & Pratten Describe Pleurotomaria carbonaria

The original description from 1855 discusses a specimen that is a small to medium-sized shell, 1 inch in length. It was said to have sharp, longitudinal ribs. This is different than the description from the Treatise on Invertebrate Paleontology, which calls these rounded cords. Perhaps variation in recovery matrix could make particular specimens have sharp ribs, or maybe there is variation across different species. Nevertheless, I believe that Norwood & Pratten’s “sharp” was a macro observation, whereas the Treatise is more of a micro observation.

Shell of medium size. Length, 1 inch; breadth, 1 l-20th inch. Whorls five, rounded, covered with strongly raised, sharp, longitudinal ribs, the grooves or furrows between which are rounded, and much broader than the ribs themselves. The sinus consists merely of a broader groove, in which there are two or three raised ribs similar to those on the remainder of the shell, but much smaller. On the inferior half of each whorl, below the sinus, both the ribs and furrows are much smaller than those on the upper portion Mouth nearly semicircular; lip sharp.

Geological Position and Locality. — This species appears to be very rare, having been found only at Rock Creek, Williamson County, Illinois, where it occurs in a black, carbonaceous shale, belonging to the coal measures.

Explanation of the Figure. — PL IX. fig. 8. View of the front and left side of an adult specimen.

Illinois State Collection.

Shansiella carbonaria, as illustrated in Plate IX (9), Figure 8 by Norwood & Pratten as Pleurotomaria carbonaria.
Figure 2—Pleurotomaria carbonaria as illustrated by Norwood and Pratten.

The description calls the species rare, only found from a shale belonging to the coal measures at Rock Creek, Williamson County, Illinois. This is clearly not the case today. In just a short amount of time, I have found reported specimens from Kentucky, Ohio, Texas, Pennsylvania, and New Mexico.

A Local Report of Pleurotomaria Carbonaria (=Shansiella Carbonaria)

In the 1910 Annals of the Carnegie Museum, Percy Raymond reported specimens from two marine horizons locally. A single specimen was illustrated from the Brush Creek, recovered from Donohoe, PA. No specimen number exists, so it is currently unknown if this is in the Carnegie’s Invertebrate Paleontology Collections managed by Albert Kollar. One interesting detail was Percy’s recalling of Conrad’s first described fossils back in 1835. It was in the 1910 publication that he discussed Turbo insectus and its similarity to Pleurotomaria carbonaria.

Pleurotamaria carbonaria as photograped by Percy Raymond. A specimen from the Brush Creek limestone of Donohoe, PA.
Figure 3—Plate XXVI, Figure 1 from Raymond’s publication. Pleurotamaria carbonaria (=Shansiella carbonaria): A specimen from the Brush Creek limestone of Donohoe, PA.

Helen Morningstar Illustrates a Specimen from the Pottsville of Ohio

In 1922, Helen Morningstar publishes a large volume on the Stratigraphy and Fossils of the Pottsville Formation in Ohio. In the section about fossils, she discusses the condition of recovered specimens and talks about there being a number of shells in an “excellent state of preservation”. She mentions that several of the different species within Pleurotomaria might be referable to P. carbonaria. The deeply depressed slit-band is discussed. Her publication includes several localities throughout Eastern Ohio and lists available species, including P. carbonaria. Five species of Pleurotomaria are discussed along with some internal molds.

Figure 4—P. carbonaria, figured by Hellen Morningstar in 1922.

T. H. Yin Creates the Genus Shansiella in 1932

As part of a report on the Gastropoda of the Penchi and Taiyuan Series of Northern China, T. H. Yin erected the new genus Shansiella. He includes two catalog numbers, No. 4788 and No. 4789 for the holotype and paratypes of the genus. They were collected from the T’umen shale in the upper Taiyuan series, an Upper Carboniferous aged series.

Paleontology is not always a safe job, despite it being grounded with peaceful intentions. Yin mentions a colleague Y. T. Chao would have done work on both Gastropods and Cephalopods from the region. However, he notes that Chao was taken by bandits in 1929. Yin was completing at least part of the work, publishing on the Gastropods of the region.

Yin’s Original Description of His New Genus Shansiella

Genus SHANSIELLA Yin (gen. nov.)
Shell of medium size, rather low spired, the maximum diameter of the last whorl being a little greater than the total height of the shell. The general outline of the whorls is rounded but a narrow spiral depression is occupied by the slit-band. The suture is deeply impressed below the ambitus and on the edge of the slit-band.

The surface of the entire shell is covered by numerous spiral lines more or less granulated. The slit-band lies immediately below the ambitus and is not very strongly excavated.

The aperture so far as it is observable is subrhomboidal with rounded corners. The external lip expands strongly outward before arriving at the margin, which is suddenly contracted. This gives rise to an ungraceful protuberance near the aperture where the suture terminates far below the slit-band of the preceding whorl. No umbilicus is present.

The genotype is Shansiella altispiralis (Grabau). The author is not acquainted with any form previously described that can be referred to this genus.

Yin figured two specimens in four views. His “ungraceful protuberance” was visible in 1a in figure 5 below. Comparing 1b and 1c, one can see how different the shape was between the two. It’s also important to note that Yin made no comparison to Pleurotomaria carbonaria. He did set his new genus under the family Pleurotomariidae. He mentions that Shansiella altispiralis was synonymous with Gyronema? altispiralis Grabau from the Permian of Mongolia.

Figure 5—Catalog No. 4788 (Holotype) and one specimen from Catalog No. 4789 (Paratype)

Eirlys Grey Thomas Erects the Genus Latischisma

In the 1930’s, Yin’s creation of Shansiella created some collisions and healthy discussion around the placement of his new snail genus. In 1940 Eirlys Grey Thomas, a Carnegie Research Scholar from the University of Glasgow, reviewed the Pleurotomariidae in the Carboniferous limestones of Scotland. In the publication, she created a new genus Latischisma. She indicated its key features being the globose shell, the flattened selenizone, and its spiral ornamentation.

The published illustrations and specimen photos are identical to specimens of Shaniella. In 1958, Roger Batten remarked about the stated differences, whereas Shansiella has coarser ornament and Latischisma has finer. He assessed that this has been found to intergrade within a single species (Batten, 1958) and therefore synonymized the two. This again touches on the corded versus sharp ornamentation difference. A few years later when the Treatise volume was published, Latischisma was listed as a synonym of Shansiella.

Knight’s Discussion on Yin’s Specimens

Nine years later, Knight (1941) reviewed Yin’s description of Shansiella and doubted Yin’s assessment of his specimens. While Yin provided photographs, the photos were all that were available to study. The specimens, No. 4788 (holotype) and No. 4789 (four paratypes) are likely in a collection in Northern China. Yin said that the aperture had an “ungraceful protuberance” on the aperture. Essentially, the nearly circular aperture was squashed down to an oval. Knight concluded that Yin was “deceived by a broken aperture distorted by pressure” (Knight, 1941). He also considered the paratype that Yin illustrated as a much better specimen.

Sturgeon’s Research from the Allegheny Formation in Ohio

Myron T. Sturgeon included detailed remarks about S. carbonaria in his paper. Along with the stratigraphic correlation of specimens across the Allegheny Formation, he discusses both Yin’s specimens and Turbo insectus. He considered Yin’s figures to not appear markedly different from his own specimens (Sturgeon, 1946). This creates some speculation of whether or not Shansiella altispiralis and S. carbonaria might be the same species.

Sturgeon was also one to openly question the validity of Turbo insectus and its relationship with S. carbonaria. He believed that the recovery of topotype material could prove the two specimens the same. Sturgeon also mentioned that since T. insectus had priority, the entire species would need to become Shansiella insectus (Conrad, 1835)

He mentions that S. carbonaria has a wide stratigraphic and geologic range and suggested a detailed study of a variety of specimens across these ranges could turn up additional species or subspecies. While in modern times efforts such as my own have helped publish visual specimens to study online, the vast majority of collections in highly respected institutions do not include photographs. They can be requested, but there is no standard path to follow and results vary by institution.

Roger Batten Creates the Family Portlockiellidae

In an effort to publish new families for the upcoming Treatise of Invertebrate Paleontology, Roger Batten published the description for a new family of gastropods named Portlockiellidae. His publication included Portlockiella Knight (1945) and the new genus Tapinotmaria. Just a few years later, the Treatise was published and the new family. S. carbonaria (Norwood & Pratten, 1855) was illustrated as a typical species of Shansiella. Knight et al. assigned Shansiella to the new family in 1960. The genus Portlockiella Knight, 1945, contrasts to Shansiella by having a deeper selenizone that is located below the upper whorl sutures. The spiral ornamentation also has broader interspaces (Amler & Heidelberger, 2003).

Roger Batten Gets Closer Than Anyone

Microscopic studies of paleontological remains can be an excellent way to gain insight into how the original creature lived. It can help with species identification in fossilized trees that require views of the cellular structure (Gar Rothwell, 2021, personal comm.). Microscopic views can show specific crystal structures of one or more layers in the shells of mollusks.

Batten provided several scanning electron microscope images of Pennsylvanian pleurotomarian gastropods in a paper published as an American Museum Novitates in 1972. S. carbonaria was featured in the vast majority of images in the paper. There is a nice cross-section of an ornamental rib presented as figure 14 in the paper. This adds more to the sharp versus rounded rib discussion. Clearly, this particular rib includes two subsidiary peaks with a small depression between them.

Figure 6—Sketch of a 118X magnified cross-section of one of the ornament ribs from S. carbonaria, specimen AMNH 29229. It showcases the crystal structure and the author points out that more complex prisms bend to fill in for the shape of the rib. The two peaks along the ornamentation cord are shown with arrows. Redrawn from figure 14 in Batten’s paper.

Another very interesting insight came from Figure 16 in the paper showing a total cross-section of S. carbonaria. Gastropods are typically interesting in this view, showing matrix-filled shell voids. The nacreous inner walls and irregular thickness of the shell at different places are discussed. I considered cutting one of my own specimens to get this view, but the photo from the article presents a great view. I illustrated Batten’s figure below.

Figure 7—Sketch of a cross-section photo of AMNH 29232. Note that while shells are often nicely preserved on the outside, the inside chambers can be quite broken like this sketch shows. The same occurs in fossil Cephalopods.

Morphometric Differences in Local Shansiella carbonaria Specimens.

The recovery of over twenty-five different specimens has yielded a variety of shell sizes. Specimens recovered from the Pine Creek locality have yielded some very detailed shell views. Shansiella found locally in the Brush Creek limestone are much more difficult to recover and observe. As part of this research, I have prepared plates. The first plate is a broad overview of specimen size. Plates 2, 3, and 4 show three views of eighteen different specimens. Plate 5 shows a rather extreme compression comparison.

Plate 1 – Views of Eleven Specimens of S. carbonaria

This plate showcases a broad range of shell sizes found in the Pine Creek and Brush Creek horizons in central and southwestern Armstrong County, Pennslyvania.

Plate 1. Shansiella carbonaria (Norwood & Pratten, 1855), from the Brush Creek and Pine Creek limestones of Armstrong County, Pennsylvania, United States. All reside in the author’s personal collection. Correlation with figure labels and specimen identification numbers is as follows: (A) CG-0218; (B) CG-0195; (C) CG-0203; (D) CG-0197; (E) CG-0202; (F) CG-0149; (G) CG-0217; (H) CG-0060; (I) CG-0189; (J) CG-0219; (K) CG-0225;

Plate 2 – Abapertural View of Eighteen Specimens of S. carbonaria

The plate below provides a good range of shell sizes and preservation throughout the Brush Creek and Pine Creek marine zones in Western Pennsylvania. The corded ornament is not always well preserved, but all eighteen specimens show at least the presence of these cords on one or more whorls. Each example averages 3-4 whorls with some variation. The smallest whorl at the spire is often well preserved, as the pyramid shape helps to prevent damage to the spire.

Plate 1, Abapertural view of S. carbonaria. 18 specimens.
Plate2—Abapertural View. Key follows plates 2-4.

Plate 3 – Adaperture View of Seventeen Specimens of S. carbonaria

The aperture is not often well preserved. Several authors focus on aperture morphology. The shell is thick-walled in this area. Specimen B and H both show a very thick shell wall. Specimen O is exceptional as it shows distinct layers within the fossil shell material.

Plate two, adaperture view of Shansiella carbonaria
Plate 3—Adaperture View. Key follows plates 2-4.
M is omitted as a photograph was not obtained in this view for this specimen.

Plate 4 – Spire View of Eighteen Specimens of S. carbonaria

The view from above the specimens is pleasing. In cleaner examples, you can see the growth lines. This is true for both specimen H and specimen O. The cords maintain visibility on each whorl when viewed from directly above.

Plate 3. View looking down on the spire on Shansiella carbonaria.
Plate 4—Spire View. Key follows plates 2-4.

Plate Key for Plates 2 – 4

Plates 2-4. Shansiella carbonaria Norwood & Pratten, 1855, from the Brush Creek and Pine Creek limestone of Armstrong County, Pennsylvania, United States. All reside in the author’s personal collection. Correlation with figure labels and specimen identification numbers is as follows: (A) CG-0218; (B) CG-0185; (C) CG-0195; (D) CG-0216; (E) CG-00142; (F) CG-0203; (G) CG-0197; (H) CG-0202; (I) CG-0166; (J) CG-0145; (K) CG-0148; (L) CG-0149; (M) CG-0215; (N) CG-0217; (O) CG-0060; (P) CG-0189; (Q) CG-0147; (R) CG-0151;

Plate 5 – Shell Compression after Burial

The following plate showcases four views of two specimens, CG-0221, and CG-0222. The former specimen is a typical recovered specimen with a full spire. The latter is highly compressed vertically.

Plate 4, four views of two specimens of S. carbonaria showing compression difference.  The first specimen is uncompressed, the second is compressed.

Plate 5. Shansiella carbonaria Norwood & Pratten, 1855, from the Pine Creek limestone Armstrong County, Pennsylvania, United States. All reside in the author’s personal collection. Correlation with figure labels and specimen identification numbers is as follows: (A1, A2) CG-0221; (B1, B2) CG-0222;. Note the difference in vertical preservation between A1 and B1. While it appears that perhaps the bottom of the shell is missing, inspection shows a full set of spiraling ornamentation on the underside.

Specimen CG-0060 and Some Excellent Feature Preservation.

The specimen CG-0060 is a smaller specimen with several well-preserved features. The outer shell material is missing at two places on the shell. Growth lines from inside the shell are clearly visible. Outer shell growth lines are also visible on this specimen. A clean separation from the matrix created an exceptional specimen when viewed up-close.

Shansiella carbonaria, exceptional specimen.
Figure 8—CG-0060, Shansiella carbonaria. Aperture view.
Shansiella carbonaria, outer shell detail.
Figure 9—CG-0060, Shansiella carbonaria, outer shell detail. Growth lines are visible. Noticeable concave lines exist along the selenizone.
Shansiella carbonaria, inner growth line detail.
Figure 10—CG-0060, Shansiella carbonaria, inner growth line details. Missing shell material in this area shows the inner growth lines on the shell. There is a noticeable sweeping shape that reaches towards the selenizone.

Juvenile Specimen CG-0219, a Tiny but Detailed Example

The scale bar on photos of CG-0219 Shansiella carbonaria is in millimeters, not centimeters. Despite its tiny size, there is a lot of detail available with this particular fossilized gastropod. The aperture is a bit more intact than typical recovered examples. In particular, the preserved growth lines are exceptional. They are difficult to see along the selenizone, but small parts can be observed. The wider channel between the costae where the selenizone runs is easy to discern.

CG-0219, Shansiella carbonaria. Aperture View.
Figure 11—CG-0219, Shansiella carbonaria. Aperture View.
CG-0219, Shansiella carbonaria. Spire View.
Figure 12—CG-0219, Shansiella carbonaria. Spire View.

Specimen CG-0226, Weathered Example

This heavily weathered specimen provides some detailed depth into the shell matrix. Most striking is the characteristic of eroded ornament structures showing differing weathering on the topmost ridges versus the central concave depression. Figure 12 shows these structures. The more solid ridges are visible with a powdery white central depression that has eroded differently.

Microscopic view of weathered ornament on CG-0226 S. carbonaria.
Figure 13—Microscopic view of weathered ornament on CG-0226 S. carbonaria. Arrows indicate ornamental ridge cross-sections that are available due to weathered shell material.

Another interesting feature of CG-0226 is how preserved the spire is. While the majority of the outer shell material has eroded away in this view, the inner shell layer is preserved. The spire wraps around the columella. The ornament lines can be seen barely on the whorl. This also shows how rapidly the whorls can expand with each revolution.

Microscopic spire view of specimen CG-0226
Figure 14—Microscopic spire view of CG-0226 S. carbonaria

Shansiella carbonaria Catalog Entries

  • All catalog specimens collected locally are available at this link.

Specimens at Different Institutions

Yale Peabody Museum

The Yale Peabody Museum has five catalog entries for S. carbonaria, all recovered from Kentucky. Some are lots, and the total number of specimens is thirteen. Two are listed under the older name Pleurotomaria carbonaria, but correct identification exists within each record. At least one of them was collected over 100 years ago, in 1919. They currently do not have photographs attached to these records. I was not able to review any of the specimens visually, but I am including them for further reference of the collected material.

University of New Mexico

In a conference paper in 1984, Barry S. Kues listed and figured a single specimen of S. carbonaria from the Flechado Formation in North Central New Mexico. Many of the listed genera are similar to ones back in Parks Township, including Metacoceras, Mooreoceras, Petalodus, Linoproductus, Worthenia, and Wilkingia. The list in his research is very comprehensive and spans eight papers over 50+ years. In another paper in 2001 Kues and Batten illustrated both UNM 7057 and 7058. UNM 7057 was said to be three times larger than UNM 7058.

  • UNM 7057
  • UNM 7058

American Museum of Natural History

Batten referenced a number of specimens of S. carbonaria over a long career of paleontology writing. He deposited eleven of them into the collection of the Division of Paleontology at the American Museum of Natural History. They have a well-functioning online catalog and to my surprise, all of Batten’s specimens were there. Three of them even include photos.

Smithsonian Museum of Natural History

Two entries in the Smithsonian Catalog. One was collected from Kentucky, the other is unknown.

Awknowledgements

I would like to express my deepest appreciation to John A. Harper for his peer review of this paper, for his help in educating me in invertebrate paleontology, and for originally pointing out the Pine Creek locality in which the majority of these specimens have been recovered.

References