Wooster’s Fossil of the Week: A fragmentary rostroconch from the Middle Devonian of Ohio

November 27th, 2015

1 Hippocardia 1Not all of our featured fossils are particularly beautiful, or even entire, but they are interesting in some way. Above is the broken cross-section of a rostroconch mollusk known as Hippocardia Brown, 1843. It was found somewhere in Ohio by the late Keith Maneese and kindly donated to the department by his widow Cameron Maneese. From its preservation and the kind of rock making up the matrix inside, we can tell that it almost certainly came from the Columbus Limestone (Middle Devonian, Eifelian).

In the top image it is apparent that this fossil has bilateral symmetry, a heart-shaped cross-section, and a ribbed calcitic shell. This is the dorsal view.
2 Hippocardia 2Flipping the specimen upside-down, we now have a view of the ventral portion. Again we see the ribs and bilateral symmetry.
3 Hippocardia side viewThis side view shows that the ribs extend from the dorsal to the ventral sides and are angled to the axis of the shell. That’s about all we can tell. (And this is the best specimen of a rostroconch we have! Thank you again, Cameron.)
4 CzechVirtualRostroThis diagram of a complete rostroconch (from the Czech Virtual Museum). This is a side view of a species that does not have the dorsal-ventral ribbing. The shell is superficially like that of a bivalve (clam), but the valves are fused together and their is a distinctive tube (rostrum) extending to the posterior. Much study and debate about the rostroconchs has at least confirmed that these are a class of mollusks separate from the bivalves. They lived semi-infaunally with the rostrum extending into the seawater to channel a flow of water into the body chamber for filter-feeding, much like infaunal bivalves today that have siphons. Rostroconchs and cephalopods appear to be sister groups, and some rostroconchs may have evolved into the scaphopods. Plenty of arguments to go around, though, on the evolution and diversification of mollusks
5 Thomas 1843 p 976 Thomas pl 8 fig 10 1843Captain Thomas Brown (1785-1862) named the genus Hippocardia in 1843. He was a Scottish naturalist who studied many topics, including mollusks. Above are the sections of his book The Elements of Fossil Conchology that describe and illustrate Hippocardia (considering it a bivalve). Captain Brown was born in Perth and went to school in Edinburgh. He joined the militia at 20, becoming a captain at 26. When he was transferred to Manchester, England, Brown acquired an interest in nature. He bought a flax mill after leaving the military, but it burned down while still uninsured. He thus turned to nature writing for support. He was became a Fellow of the Royal Society of Edinburgh in 1818, and in 1840 he was appointed curator of the Manchester Museum. He retained this position for the rest of his life. He was later a Fellow of the Linnean Society and a member, in classic 19th Century fashion, of several other groups, including the Wernerian, Kirwanian and Phrenological Societies. (I love the addition of phrenology to his interests!) The marine gastropod Zebina browniana d’Orbigny, 1842, was named after him. An interesting character, this Captain Brown, but I’ve been unable to find a single portrait of him.


Brown, T. 1843. The elements of fossil conchology according to the arrangement of Lamarck; with the newly established genera of other authors. Houlston & Stoneman, London; 133 pages.

Hoare, R.D. 1989. Taxonomy and paleoecology of Devonian rostroconch mollusks from Ohio. Journal of Paleontology 63: 838-846.

Pojeta, J., Jr., Runnegar, B. 1976. The paleontology of rostroconch mollusks and the early history of the phylum Mollusca. United States Geological Survey Professional Paper 968: 1-88.

Pojeta, J., Jr., Runnegar, B., Morris, N.J. and Newell, N.D. 1972. Rostroconchia: a new class of bivalved mollusks. Science 177: 264-267.

Runnegar, B., Goodhart, C.B. and Yochelson, E.L. 1978. Origin and evolution of the Class Rostroconchia [and discussion]. Philosophical Transactions of the Royal Society B: Biological Sciences 284(1001): 319-333.

Wagner, P.J. 1997. Patterns of morphologic diversification among the Rostroconchia. Paleobiology 23: 115-150.

Wooster’s Fossil of the Week: A tall brachiopod from the Devonian of western Russia

November 20th, 2015

1 Ladogia Nalivkin, 1941In the summer of 2009 I had a field adventure in Russia. It was an extraordinary time. I learned considerable amounts of Russian geology and paleontology, of course, and was immersed in the Russian geological culture. Along the way I collected the above unusual brachiopod. We are looking at its posterior (where the articulating hinge is), with the ventral valve below and dorsal valve above.
2 Ladogia Nalivkin, 1941This is the anterior view of the same specimen showing the junction between the valves (the commissure). The brachiopod is Ladogia Nalivkin, 1941, a rhynchonellid from the Upper Devonian (Frasnian) of the Central Devonian Field somewhere along the Syas River in the Leningrad Oblast of western Russia. We can immediately see that this brachiopod is very tall for its kind, with a strongly defined fold (the top part of the “anticline” in the dorsal valve) and sulcus (the lower folded surface in the  ventral valve). Note that the sulcus has several encrusting organisms, including eroded microconchids.
3 Ladogia Nalivkin, 1941The side view shows the dramatic upward sweep of the dorsal valve and the fine radiating ornamentation. The tall fold was effective in separating the incoming water for filter-feeding from the outflow of filtered water, essentially functioning like a chimney. Many brachiopods have such a fold and sulcus, but few have a set of such amplitude.
4 Nalivkin, Dmitrii VasilevichLadogia was described by Dmitrii Vasil’evich Nalivkin (1889-1982) in 1941. Nalivkin was a Soviet paleontologist and geologist born in 1889 in St. Petersburg. He graduated from the Institute of Mines in Petrograd (the name was changed from St. Petersburg) in 1915. In 1917 he joined the Geological Commission of Russia, staying a member through its many changes for over six decades. In 1920 he became a professor at the Institute of Mines after, we presume, the political situations from the Great War, the Bolshevik Revolution and the Russian Civil War calmed down. He is notable for giving the first lecture series on facies theory in the USSR in 1921. After World War II he was chairman of the Turkmen section of the Academy of Sciences. In 1954 he was made chairman of the Interdepartmental Stratigraphic Committee of the Academy of Sciences of the USSR. In 1954 he was appointed chairman of the Interdepartmental Stratigraphic Committee of the Academy of Sciences of the USSR. Nalivkin specialized in stratigraphy and paleontology of the Paleozoic, especially the Devonian and Carboniferous. He is best known for his geological maps of the USSR, for which he received the Lenin Prize in 1957. Here’s a man who saw a lot of history in his time.


Nalivkin, D.V. 1941. Brachiopods of the Main Devonian field. Akademii Nauk SSSR Trudy 1: 139-226.

Sokiran, E.V. 2002. Frasnian-Famennian extinction and recovery of rhynchonellid brachiopods from the East European Platform. Acta Palaeontologica Polonica 47: 339-354.

Zhuravlev, A.V., Sokiran, E.V., Evdokimova, I.O., Dorofeeva, L.A., Rusetskaya, G.A. and Malkowski, K. 2006. Faunal and facies changes at the Early-Middle Frasnian boundary in the north-western East European Platform. Acta Palaeontologica Polonica 51: 747-758.

Wooster’s Fossil of the Week: A striated brachiopod from the Silurian of New York

November 13th, 2015

6 StriispiriferCalebsSometimes it is a Fossil of the Week simply because it is new to me. The brachiopods above are abundant in a thin layer of shells within the Lewiston Member of the Rochester Shale (Silurian, Wenlockian) in western New York State. They are well exposed in the magnificent Caleb’s Quarry a few colleagues and I visited this past summer.
2 Striispirifer niagarensis Bed 9 Mbr D

3 Striations Sheinwoodian 585I find this spiriferid brachiopod fascinating because of the fine striations it shows on its fold and sulcus (where the shell bends at its middle). I’ve never seen these before on a brachiopod. The species is Striispirifer niagarensis (Conrad, 1842). I know of no functional interpretation of these fine lines other than that they might have provided some micro-topography to dissuade encrusting organisms. (I observed, in fact, no encrusters on these shells, but that may be coincidence.) The Striispirifer shell pavement consists mostly of isolated valves, but there are occasionally clusters of articulated shells in living position. It appears likely this is a storm lag of shells that was later colonized by the same brachiopods composing it.
4 Conrad description niagaraensisWe met the species author Timothy Abbott Conrad (1803-1877) earlier in this blog. He described this brachiopod originally as Delthyris niagaraensis in 1842 (above). (The third “a” in the species name was dropped by James Hall in his species lists.) This name held for over a century until G. Arthur Cooper and Helen Muir-Wood discovered that the genus was also in use for another brachiopod named in 1828 by Johan Wilhelm Dalman. This made “Delthyris” a homonym, or a name for a taxon identical in spelling to another such name for a different taxon. We can’t have that, of course, since every genus name must be unique (at least among the animals). Cooper and Muir-Wood (1951) gave the later genus (the junior homonym) the new name Striispirifer. Paul Taylor and I recently had our own adventure with a homonym we inadvertently created.
5 Helen Muir Wood 1955 Jill DarrellHelen Muir-Wood (1896-1968) was one of the most prominent brachiopod experts of the 20th Century. The image above may be the first one of her online. (Thanks to Jill Darrell of the Natural History Museum, London, for providing it. Come to think of it, the earlier image of Rousseau Hayner Flower in this blog is likely the first picture of him on the web.) Muir-Wood was born in Hampstead, England, and educated at Bedford College, University of London (a college for women at the time). She joined the professional staff at the British Museum (Natural History) in 1922 and spent the next 43 years of her career there. She was a systemacist to the core, apparently intolerant of any work with with fossils outside of describing and classifying them. Although she did no fieldwork of her own, from her position at the museum she was able to study brachiopods from around the world. She pioneered the techniques of describing brachiopod internal structures and eventually had to her credit hundreds of new and redescribed taxa. She was awarded the Lyell Medal in 1958 for her achievements, and in 1965 received the Order of the British Empire. She was remarkably successful and her work is still heavily cited to this day.


Ager, D. 1969. Helen Marguerite Muir-Wood. Proceedings of the Geologists’ Association 80: 122-124.

Brett, C.E. 1983. Sedimentology, facies and depositional environments of the Rochester Shale (Silurian; Wenlockian) in western New York and Ontario. Journal of Sedimentary Research 53: 947-971.

Conrad, T.A. 1842. Observations on the Silurian and Devonian Systems of the United States, with descriptions of new organic remains. Journal of the Academy of Natural Sciences of Philadelphia 8: 228–280.

Cooper, G.A. and Muir-Wood, H.M. 1951. Brachiopod homonyms. Journal of the Washington Academy of Sciences 41: 195-196.

Dalman, J.W. 1828. Uppställning och Beskrifning af de i sverige funne Terebratuliter. Kongl. Svenska Vetenskaps Academiens Handlingar, für 1827, 1828; Stockholm, tryckt hos P.A. Norstedt & söner, pp. 93, 99.

Williams, A. 1969. Helen Marguerite Muir-Wood. Proceedings of the Geological Society of London 1655: 123-125.

Wooster’s Fossil of the Week: Reptile tracks from the Lower Permian of southern Nevada

November 6th, 2015

1 Komodo on slab side viewAlways lead with your most interesting image. The fossil here is the thin orange slab of siltstone underneath my magnificent Komodo Dragon model.
2 Footprints slabHere is the slab itself. On the far right and the far left you can see two fossil footprints from both sides of some ancient reptile. The plastic Komodo Dragon just happens to fit these prints in size and shape, but they certainly weren’t made by an actual Komodo Dragon. I found this rock in the Spring Mountains of southern Nevada while doing my doctoral dissertation fieldwork decades ago. It is from the Lower Permian of the massive Bird Spring Formation (which is almost a mile thick). The footprints had nothing to do with my work (I was concentrating on the Carboniferous part of the formation), so I kept this little slab as a memento at home.
3 Back right track copyThese tracks, a kind of trace fossil, belong to the ichnogenus Dromopus based on the slender nature of the elongated toes. Dromopus has been attributed to an araeoscelid reptile, which looked and apparently lived very much like a modern lizard.
4 Araeoscelis grandis by Smokeybjb WikipediaAraeoscelis is one of the earliest diapsid reptiles, a group that has two distinctive holes (temporal fenestrae) on the sides of its skull. Diapsids are the most common type of reptile today, including crocodiles, lizards, snakes and dinosaurs. This genus was small, growing only to about 50 cm, and apparently predatory on insects and other arthropods. (Image from Smokeybjb via Wikipedia.)

5 Komodo top view on slabAgain, my friendly Komodo Dragon is only a stand-in for the Permian tracemaker, but he does have a nice pose to fit the tracks of his ancestral cousin!


Haubold, H. and Lucas, S.G. 2003. Tetrapod footprints of the Lower Permian Choza Formation at Castle Peak, Texas. Paläontologische Zeitschrift 77: 247-261.

Hunt, A.P. and Lucas, S.G. 2006. Permian tetrapod ichnofacies. Geological Society, London, Special Publications 265: 137-156.

Hunt, A.P., Lucas, S.G., Lockley, M.G., Haubold, H. and Braddy, S. 1995. Tetrapod ichnofacies in Early Permian red beds of the American Southwest. New Mexico Museum of Natural History and Science Bulletin 6: 295-301.

Lucas, S.G. 2002. Global Permian tetrapod footprint biostratigraphy and biochronology. Permophiles 41: 30-34.

Wooster’s Fossil (Maybe) of the Week: Kinneyia ripples

October 23rd, 2015

1 Kinneyia_Grimsby_Silurian_Niagara_Gorge_585While hiking through the Niagara Gorge on a field trip in August, my friend Andrej Ernst of the University of Kiel found the above block of siltstone from the Grimsby Formation (Silurian) with unusual small-scale ripples in a patch. Carl Brett (University of Cincinnati) immediately identified it as a sedimentary structure/fossil known since 1914 as Kinneyia. This name was new to me. I had long called such features “elephant skin”, but I’ve now learned that these “sedimentary wrinkles” have a long and sometimes contentious history of study, and they have significant variability (see references).

Charles Doolittle Walcott (1850-1927) was one of the best known and productive invertebrate paleontologists. An American, he most famously discovered the Cambrian Burgess Shale in western Canada with its fantastic soft-tissue preservation. Walcott was especially fascinated with finding the earliest evidence of life, so he intently studied rocks older than the Cambrian (an interval we used to call the Precambrian). In 1914 he published a compendium of what we considered to be fossil algae, including Kinneyia. Below is his original description followed by his photographic image.
2 Walcott 1914 1073 Screen Shot 2015-08-22 at 6.42.01 PM4 Screen Shot 2015-08-22 at 6.42.57 PMWe now know that these curious structures are not fossilized algae, hence the name Kinneyia no longer has any biological use. (You may note that most authors do not italicize the name, emphasizing that it is no longer a valid taxon. I keep the style as a reminder of the name’s history.) These are ripples with sinuous, bifurcating, flat-topped crests. They are sometimes very complicated when the crests interfere with each other. Their flat tops (when well-preserved) suggest that there was something lying above them. Most workers on Kinneyia conclude that this was a microbial mat, so Walcott would be at least satisfied that life was involved. Did the Kinneyia ripples form as gas built up underneath a decaying mat? Are they made when the mat shrinks through desiccation? Experimental physicists have even gotten involved in the interpretations. Thomas et al. (2013) write: “Microbial mats behave like viscoelastic fluids. We propose that the key mechanism involved in the formation of Kinneyia is a Kelvin-Helmholtz type instability induced in a viscoelastic film under flowing water. A ripple corrugation is spontaneously induced in the film and grows in amplitude over time.”

Kinneyia is thus a sedimentary feature formed by physical processes mediated by life in the form of a microbial mat. What those processes were is the most interesting question now.


Gerdes, G., Klenke, T. and Noffke, N. 2000. Microbial signatures in peritidal siliciclastic sediments: a catalogue. Sedimentology 47: 279-308.

Hagadorn, J.W. and Bottjer, D.J. 1997. Wrinkle structures: Microbially mediated sedimentary structures common in subtidal siliciclastic settings at the Proterozoic-Phanerozoic transition. Geology 25: 1047-1050.

Noffke, N., Gerdes, G., Klenke, T., Krumbein, W.E. 2001. Microbially induced sedimentary structures — a new category within the classification of primary sedimentary structures. Journal of Sedimentary Research A71: 649-656.

Porada, H., Ghergut, J. and Bouougri, E.H. 2008. Kinneyia-type wrinkle structures—critical review and model of formation. Palaios 23: 65-77.

Thomas, K., Herminghaus, S., Porada, H. and Goehring, L. 2013. Formation of Kinneyia via shear-induced instabilities in microbial mats. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences 371(2004), 20120362.

Walcott, C.D. 1914. Cambrian geology and palaeontology III No.2 – Precambrian, Algonkian algal flora. Smithsonian Miscellaneous Collections 64: 77-156.

Wooster’s Fossil of the Week: an upside-down nautiloid from the Devonian of Wisconsin

October 16th, 2015

1 Poterioceras calvini Milwaukee Formation DevonianThis lump of a fossil in Wooster’s teaching collection requires some explanation. It is not particularly well preserved, but it is our only representative of an interesting group of nautiloid cephalopods. The label that came with it says it is Poterioceras calvini, but I see no reason to believe it. There are simply not enough characters visible to identify it to the genus level, let alone the species. We should confine it to a higher taxon: Order Oncocerida Flower in Flower and Kummel, 1950. It comes from the Wisconsin Dolomite (Devonian) exposed in the city of Milwaukee.
2 Poterioceras calvini Milwaukee Formation DevonianOn the left-hand side (with the scale) of each image you may barely make out vertical partitions, shown as faint lines. These are sutures, which represent the junction between internal septal walls and the outer shell. The shell has dissolved (since it was made of more soluble aragonite), leaving this internal mold fossil. The right side of the fossil shows no such partitions because it is where the large body chamber was located. The nautiloid animal lived in the body chamber, with the septal walls (and the chambers they delineated) behind it as the phragmocone.
3 Gomphoceras cartoon 585This diagram from Wikipedia may make sense of this anatomy. The chambered phragmocone is shown in the top left, colored yellow; the body hangs below it in the body chamber. The phragmocone was filled with a mixture of gases and liquids, giving it positive buoyancy relative to the negatively-buoyant body chamber. The nautiloid thus in life hung upside-down facing the seafloor as it floated about. The cartoons on the right show the shell itself, including the keyhole aperture that kept the body from falling out.
4 orthoconeCompare this to the typical orientation of a Paleozoic nautiloid (above). Both of these nautiloid types were nektic (swimming) predators. The oncocerid just did it by hanging upside-down!
5 RH Flower 585The Order Oncocerida was named and described by one of the 20th Century’s most eccentric paleontologists, Rousseau Hayner Flower (1913-1988). I never met Dr. Flower, but I stumbled into a memorial session for him at the 1988 annual Geological Society of America meeting, which was held that year in Denver. Some people were barely holding back tears, others were laughing, and one crusty old paleontologist stormed out muttering “He was a bastard!”. I knew then that Flower was a character. (The photograph is from Wolberg, 1988, inside front cover.)

Rousseau Flower was born in a small town in upstate New York in 1913. He was both musically and scientifically gifted, winning a scholarship to Cornell University where he trained in entomology, eventually earning an M.A. degree there. An interest in fossil dragonflies drew him into paleontology, and a chance to take an extended geological field trip sealed his new interest in fossils. He had an eventful few years in the New York State Museum and the University of Indiana, finally earning his PhD at the University of Cincinnati in 1939. After bouts of unemployment during the war years, he went back to the New York State Museum to fill various temporary positions. In 1951 he took a job as Stratigraphic Geologist at the State Bureau of Mines & Mineral Resources in New Mexico, where he stayed for the rest of his life.

Flower took on his new Western identity with gusto, wearing cowboy garb and sometimes brandishing a bullwhip. He traveled the world studying corals and cephalopods and amassing an enormous collection that people are still sorting through. He published some 1800 pages of paleontological work, naming dozens of new taxa and making major contributions to our understanding of cephalopod evolution and paleobiology, coral systematics, and western North American stratigraphy. He was acerbic and, shall we say, confident in his analyses, so he made as many enemies as friends. Over half of his work was published in the memoir series of the New Mexico Bureau — so much that some suspected it was his private journal. On top of all this, he was also a prominent music and arts critic in New Mexico. Rousseau Flower earned his fearsome reputation!


Flower, R.H. and Kummel, B. 1950. A classification of the Nautiloidea. Journal of Paleontology 24: 604-616.

Mutvei, H. 2013. Characterization of nautiloid orders Ellesmerocerida, Oncocerida, Tarphycerida, Discosorida and Ascocerida: new superorder Multiceratoidea. GFF 135: 171-183.

Wolberg, D.L. 1988. Rousseau Hayner Flower, p. viii-x, in: Contributions to Paleozoic Paleontology and Stratigraphy in Honor of Rousseau H. Flower. New Mexico Bureau of Geology & Mineral Resources, Memoir 44, 415 pp.

Wooster’s Fossils of the Week: A rugose coral and its encrusters from the Middle Devonian of New York

October 9th, 2015

Heliophyllum halli Bethany Center Centerfield 2 585This week’s fossils were found on a most excellent field trip to the Niagara region of New York in August. One of our outcrops was a small patch of gravel in Bethany Center where the Centerfield Limestone Member of the Ludlowville Formation (Givetian, Middle Devonian) was exposed. My colleagues and I found many interesting fossils here. The largest specimen I collected was the above rugose coral.
1 Heliophyllum halli Bethany Center Centerfield 2 copyIt is Heliophyllum halli Milne-Edwards and Haime, 1850. This species is very common throughout the Devonian Hamilton Group of New York, Ontario and surrounding areas. The 90-degree bend in the specimen is a result of the living coral being knocked over onto its side and then twisting to grow upwards again.
3 Rugose Bethany Center Centerfield 3These corals are called “rugose” because of their “wrinkled” exteriors, easily seen in this view. The solitary forms, like this one, are a single corallite that held one polyp in life. Their conical growth form gives them another nickname: “horn corals”. Rugose corals also come in colonial varieties, which we’ve covered before in this blog. Their skeletons are made of thick calcite, so they are almost always well preserved. These corals are distinguished from others by their strong internal vertical walls (septa) and relatively few horizontal or angled partitions (tabulae and dissepiments). They lived like most other corals as sessile benthic (stationary on the bottom) predators catching food with their tentacles. It is still uncertain whether they had photosynthetic symbionts (zooxanthellae) like modern corals. Emily Damstra has a nice reconstruction of living Heliophyllum halli.
4 Encrusting Bryozoan Bethany CenterThis particular coral has a collection of encrusting organisms on its exterior. Above is a remnant of a bryozoan.
5 Microconchid Bethany CenterThe encrusting coiled shell in the lower left is a nice microconchid (a mysterious lophophorate) and at the top is another type of bryozoan. Many of these encrusters are found on eroded parts of the coral skeleton, so they likely encrusted it after death.

Heliophyllum halli was named by Milne-Edwards and Haime in 1850. We’ve introduced Henri Milne-Edwards (1800-1885) before, and even James Hall (1811–1898) for whom the species is named. Jules Haime (1824-1856) is less known. He died too young at age 32, which may explain why we have no images of him. HIs father was a prominent physician, Auguste Haime (1790-1877). Jules, like many 19th Century paleontologists, started in medicine (studying in Tours) but gravitated toward the excitement in natural history, becoming a zoologist and paleontologist. He specialized in corals, joining up early in his career with Milne-Edwards. Haime rose fast in his new profession. One year before his death he became a professor of natural history at the Lycée Napoléon in Paris. In 1856 he was appointed vice-president of the Société géologique de France, but died a few months later.


Baird, G.C. and Brett, C.E. 1983. Regional variation and paleontology of two coral beds in the Middle Devonian Hamilton Group of Western New York. Journal of Paleontology 57: 417-446.

Brett, C.E. and Baird, G.C. 1994. Depositional sequences, cycles, and foreland basin dynamics in the late Middle Devonian (Givetian) of the Genesee Valley and western Finger Lakes region. In: Brett, C.E., and Scatterday, J., eds., Field trip guidebook: New York State Geological Association Guidebook, no. 66, 66th Annual Meeting, Rochester, NY, p. 505-585.

Milne-Edwards, H. and Haime, J. 1850-1854. A monograph of the British fossil corals. London, Palaeontographical Society. 736 pages.

Wooster’s Fossil of the Week: A spherical bryozoan from the Upper Ordovician of northeastern Estonia

October 2nd, 2015

1 Esthoniopora Kukruse 585Way back in July 2007 we had our first Team Estonia doing geological field research. Andrew Milligan (’08) and I, with our friend Dr. Olev Vinn of the University of Tartu, explored the Upper Ordovician of the northeastern part of the country, perilously close to the Russian border. Most of our work was stratigraphic and related to echinoderms, but I picked up several of these beautiful spherical bryozoans. This specimen comes from the Kiviõli Member, Viivikonna Formation, Kukruse Stage, Upper Ordovician, of Kohtla-Nõmme Quarry (N 59.35665º E 27.22343º). You won’t find the quarry on a map, though, because it was soon afterwards erased by continual mining. Now it is a grassy field. Since we are studying bryozoans this week in my Invertebrate Paleontology course, I’m bringing these specimens to the blog.

2 Esthoniopora subsphaericaThis is what two specimens of this bryozoan look like before cutting. They have the size and shape of golf balls.

3 Esthoniopora subsphaericaHere are the same two specimens cut in half and polished to show the growth rings and tubular zooecia (which held the feeding zooids of the living bryozoan).

4 Esthoniopora subsphaericaIn this closer view you can see the polygonal outlines of the zooecia, now filled with calcite. In the lower right is a boring that cut through the skeleton soon after the bryozoan’s death on the Ordovician seafloor. It has a bit of sediment that filled the boring except for the very center, which apparently held the body of the borer.

This bryozoan is the trepostome Esthoniopora subsphaerica (Bassler, 1911). Bassler originally called it Hemiphragma subsphaericum, which is a nod to its abundant hemiphragms (curving partitions in the zooecial tubes). As bryozoans go, this one has a fairly simple structure with no exozone, endozone, monticules or spines. How it lived on the seafloor with such a spherical shape is a bit of a mystery. A slightly flattened patch is probably where the sphere contacted the sediment. The borings in these bryozoans were studied by Wyse Jackson and Key (2007).

5 Ray BasslerThe species author, Raymond S. Bassler (1878-1961), was an American paleontologist prominent in the study of bryozoans and other encrusting organisms. He was born in Philadelphia and became very interested in fossils from childhood. He received his bachelor’s degree from that paleontological bastion the University of Cincinnati in 1902, followed quickly by his master’s (1903) and PhD (1905) degrees from George Washington University, where he served as a professor for over forty years. He also began work at the United States National Museum in Washington in 1910, rising through the ranks to become Head Curator in 1929. His main interests were bryozoans from the Cenozoic of the Gulf and Atlantic coasts, on which he had long collaborations with the French bryozoologist Ferdinand Canu. He also worked closely with Charles Schuchert, Carl Ludwig Rominger, and Edward Oscar Ulrich. Ray Bassler died in 1961.


Bassler, R.S. 1911. The Early Paleozoic Bryozoa of the Baltic Provinces. Bulletin of the US National Museum 77: 1-382.

Koromyslova, A.V., Fedorov, P.V. and Ershova, V.B. 2009. New records of bryozoans from the Lower Ordovician of the Leningrad Region and intercolonial variability in Esthoniopora lessnikowae (Modzalevskaya). Paleontological Journal 43:39–45.

Wyse Jackson, P.N. and Key, M.M. 2007. Borings in trepostome bryozoans from the Ordovician of Estonia: two ichnogenera produced by a single maker, a case of host morphology control. Lethaia 40: 237-252.

Wooster’s Fossil of the Week: “Lapis Judaicus” from the Middle Jurassic of southern Israel

September 25th, 2015

Pseudocidaris spine 371Paul Taylor (Natural History Museum, London) is, along with his other talents, an expert on the folklore of fossils. His accounts of how fossils have been used and imagined in the past are fascinating, especially to paleontologists who work with them every day. (We had an example this summer at Whitby, England, with Saint Hilda and the ammonites.) So I was primed when Tim Palmer told me about an article on “Lapis Judaicus” or “Jews’ Stone” by Christopher Duffin (2006). Tim thought the medicinal value of these things was particularly appropriate for me.

At the top of this post is a clavate (club-shaped) spine from the echinoid Pseudocidaris. I collected it years ago from the Matmor Formation (Middle Jurassic, Callovian) exposed in Makhtesh Gadol, southern Israel. In classical and medieval times this would have been a Jews’ stone (or jewstone). Its shape is critical, of course, but also its provenance in the Middle East.
Gesner 1565 figureThis is an illustration from Gesner (1565) showing a set of Jews’ stones (taken from Duffin, 2006, fig. 2). The image on the right (“.3”) is very close to our Pseudocidaris spine. The range of shapes for Jews’ stones was broad; all simply had to have this general clavate appearance and be from the Holy Lands.

Jews’ stones are examples of a kind of sympathetic magic attached to natural objects. It was thought that the globular shape of these spines resembled a bladder, and so these stones could be used to treat urinary disorders of various kinds. Sometimes the ancient prescriptions called for them to be sucked, but more often the stones were ground into a powder and combined with other exotic ingredients for consumption either orally … or other ways. The Jews’ stones were thought to have both preventative value as well as curative.

And that is why Tim recommended them to me. One of their primary uses was for the cursed kidney stones.

Nice to know I could have a potential treatment available right there on the outcrop!


Duffin, C.J. 2006. Lapis Judaicus or the Jews’ stone: the folklore of fossil echinoid spines. Proceedings of the Geologists’ Association 117: 265-275.

Gesner, C. 1565. De Rerum Fossilium. Lapidum et Gemmarum maxime, figures et similitudinibus Libel’: non solum Medicis, sed omnibus rerum Naturae ac Philologiae studiosis, utilis et jucundus futurus. Publisher unknown, Zürich.

Gould, S.J. 2000. The Jew and the Jew Stone. Natural History 6: 26-39.

Team Yorkshire gets all geochemical

September 20th, 2015

1 MMlab091915BRYN MAWR, PENNSYLVANIA–When we last saw Mae Kemsley (’16) and Meredith Mann (’16) in this blog, they were celebrating the end of their Senior Independent Study summer fieldwork on the coast of North Yorkshire, England. This weekend the three of us traveled to Bryn Mawr College and the geochemistry lab of Professor Pedro Marenco to start the geochemical analysis phase of our research. We learned a lot under Pedro’s kind and generous direction.

2 CW715 090315 belemnitesBoth Mae and Meredith have belemnite fossils in their field collections. Meredith has just a few from the Passage Beds Member of the Coralline Oolite Formation (Upper Jurassic, Oxfordian); Mae has dozens from the Speeton Clay (Lower Cretaceous). A belemnite was a marine squid-like cephalopod that had a hard, bullet-shaped internal structure called a guard (shown above). These guards are made of almost pure calcite which took in trace elements from the seawater as they grew. The carbon and oxygen isotopes in their calcite crystals also reflect the isotopic composition of the seawater. These fossils are thus geochemical repositories from ancient seas. We are interested in what our belemnites tell us about the ambient chemical conditions in their environments, which in turn are proxies we can use to interpret paleotemperatures and other factors.

3 Belemnite cut sampleIn our Wooster geology labs we cut small disks from a series of belemnites, then polished the surfaces and cleaned them thoroughly. We brought these prepared disks to Pedro’s lab in Bryn Mawr.

4 Drilling 091915Mae is here in the Bryn Mawr petrography lab using a small drill to excavate fine calcite powder from the belemnite disks. This powder, measured in fractions of a gram, was then collected into sheets of weighing paper, folded like origami and taped to keep it in place.

5 Weighing091915Mae and Meredith are here weighing the powder samples with Pedro’s fancy balances. Each plastic sample vial had to be paced through an ion generator to reduce static charge and improve measurements to the microgram. A lot of chemwipes, weighing sheets, and gloves are used in the process to reduce contamination.

6 Mae tubes 091915After dissolving the powder samples in acid, and then diluting the liquids in carefully-measured ways, we finally ended up with these precious tubes filled with essence de belemnite. We learned how much work goes into preparation of geochemistry samples — a lot!

7 ICP MS 0091915The liquid samples are now ready for analysis in a device called an ICP-MS, which stands for Inductively Coupled Plasma Mass Spectrometer. This is the process and equipment Wooster geologists Mary Reinthal (’16) and Chloe Wallace (’17) described in their recent geochemistry blogpost. We’re doing the same thing: assessing the trace elements in our samples. Pedro will later run our samples through this magic machine and give us the results. We have a duplicate set of drilled belemnite powders to send to another lab for carbon and oxygen isotope analysis.

8 Katherine Pedro 091915Thank you very much to our Bryn Mawr hosts Dr. Katherine Nicholson Marenco (’03) and Dr. Pedro Marenco. We are very much looking forward to our continuing collaboration. Thanks as well to Dr. Paul Taylor of the Natural History Museum in London who was our Essential Companion in the field.

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