Wooster’s Fossil of the Week: A crinoid-rich Lower Carboniferous siderite concretion (part II — the inside story)

January 12th, 2014


1 Cross-section macro 2 121413Last week’s specimen was a Lower Carboniferous fossiliferous siderite concretion from an unknown location, but likely from the Wooster area. It was donated to the department by Emeritus Geology Professor Sam Root. The concretion has beautiful crinoids preserved in it, including several stems of at least two types and three calices (crowns or heads).

I took a chance and cut the concretion with a rock saw if there were interesting features on the inside. There were indeed! In the image above you see at the bottom a cross section through a broken crinoid stem showing the articulated columnals. Above it are sections of crinoid arms (the white and grey spots) each trailing a pair of delicate pinnules (the feeding parts of the arms that carried tube feet). The arms are coming from an intact calyx that is not in the plane of the section.
2 Micro 1 121413In this closer view of the above stem we see the complex anatomy of the crinoid stem. We also see the amazing mineralogy of these specimens in a way we could not from the outside. The light brown matrix is, as we’ve said, the concretion made primarily of siderite (an iron carbonate) and clay. The crinoid columnals, which were originally made of calcite (calcium carbonate), have a silvery metallic material replacing them. This is the iron sulfide mineral marcasite. The white mineral on the inside of the stem on the left is quartz (silicon dioxide). It filled in open spaces inside the stem. To confuse things (nothing is ever easy in this business!) on the right end of the stem marcasite has filled in the cavities instead of quartz.
3 Macro close 121413This view of another stem in cross-section shows a fourth mineral in the system: calcium carbonate. It can be seen as the glassy material in the middle of the structure. It is not the original calcite that made up the columnals. It is instead a later mineral that, like the quartz and marcasite in the previous image, filled in open spaces within the stem. The marcasite, quartz and calcite are thus secondary minerals introduced to the fossil long after its burial. We call these chemical and physical changes to the original mineralogy diagenesis.
4 Fearnhead 2008 Fig 2Since this cross-section view of the crinoid stems is surprisingly complicated, here is a diagram from Fearnhead (2008, figure 2). The top is a crinoid columnal looking at its articulating surface. At the bottom is a cross-section. In our crinoids you can easily make out the lumen as a hollow space running through the center of the stems (filled with marcasite, calcite or quartz). The zygum is that portion of the columnal replaced by marcasite.

Lat week I mentioned that there was a molluscan surprise revealed upon cutting open this concretion. I’ll save that for part III of this series. Same channel next week!


Fearnhead, F.E. 2008. Towards a systematic standard approach to describing fossil crinoids, illustrated by the redescription of a Scottish Silurian Pisocrinus de Koninck. Scripta Geologica 136: 39-61.

Wooster’s Fossil of the Week: A crinoid-rich Lower Carboniferous siderite concretion (part I)

January 5th, 2014

Cobble Top 121413Last year Wooster emeritus geology professor Sam Root generously donated the above pictured siderite concretion to our paleontology collections. He had received it from a friend who didn’t know where it came from originally so we have no location. The fossils in it, though, show it is Lower Carboniferous in age and could well be from local outcrops of the Cuyahoga Formation. Sam knew this is a cool specimen so he wanted to see what we could make of it.

In the top view we can see crinoid stems running transversely across the surface. Remarkably, two crinoid calices (the arm-bearing crown of the crinoid at the top of the stem) are visible. The larger one is in the lower left. You can see the top of the stem to the farthest left, and then the calyx and attached arms to the right. The second calyx is in the upper right with the arms extending down and towards us. Finding one crinoid calyx with the delicate arms still attached is impressive; finding two in the same slab is a real treat.
Siderite Concretion Carboniferous 585Above is the other side of the concretion. Again a crinoid stem can be seen transverse across the surface. This stem is different from those on the other side, though. It does not have external sculpture, and it is separated into distinct pluricolumnals as if someone sawed through it at regular intervals.
Cobble closer 121413A closer view of the above shows yet another crinoid calyx, this one almost entirely buried in the rock with the arms extending to the surface. The arms have smaller sub-arms (pinnules) still attached. Amazing.

The concretion is made of the mineral siderite (an iron carbonate) that precipitated in fine-grained sediments around the fossils after they were buried. This usually takes place under subsurface anoxic and slightly acidic conditions. The crinoids with all their small and easily-disarticulated parts were buried quickly on the ancient seafloor, probably by a storm-induced pulse of silts and clays. The decay of their soft parts produced hydrogen sulfide gas ad carbon dioxide, triggering the geochemistry that caused the precipitation of siderite around them. The hard concretion that resulted was likely in a matrix of soft shale. The strength of the siderite kept the fossils from being crushed by the weight of sediment above. At some point many millions of years later, the shale eroded away and the concretion was freed to be picked up by some lucky person.

The crinoid stem that is divided into regular increments is interesting on its own. These segments with multiple columnals (the poker chip-like individual elements) are called pluricolumnals. They likely broke at pre-set weaknesses in the connective tissue of the living crinoid, something we see in their living descendants. This may have allowed them to break off their stems (autotomize) when in danger so that the calyx and remaining stem could float away for re-establishment elsewhere.

This concretion is so interesting that I (forgive me, Sam) could not resist cutting it open to see what is inside. The inner view is even more fascinating and will be revealed next week in part II of this story. As a teaser, it involves four minerals and a surprising mollusk!


Baumiller, T.K. and Ausich, W.I. 1992. The broken-stick model as a null hypothesis for crinoid stalk taphonomy and as a guide to the distribution of connective tissue in fossils. Paleobiology 18: 288-298.

Gautier, D.L. 1982. Siderite concretions; indicators of early diagenesis in the Gammon Shale (Cretaceous). Journal of Sedimentary Research 52: 859-871.

Wooster’s Fossil of the Week: Glyptodon carapace fragment from the Pleistocene

December 29th, 2013

Glyptodon carapace fragment Pleistocene 585This is a tiny bit of a large and fascinating Pleistocene animal from Central and South America. It is Glyptodon, an impressively large mammal with bony armor much like its cousin the armadillo. The above fossil is a fragment of that carapace. Each roundel is called a scute.
Glyptodon carapace side 585This is a side view of the above carapace fragment showing its thickness and layered, bony nature.
Glyptodon ReconstructionThis modern reconstruction of Glyptodon (from Wikipedia with a GNU free documentation license) shows its primary features, including the bony shell (the size and shape of a Volkswagen Beatle, as is often stated) and its characteristically large claws. It belongs to the Superorder Xenarthra, which includes armadillos, sloths and anteaters. I see the resemblance. They could not completely go turtle, as it were, but it could pull its head back enough into the shell that the scutes on the top of the skull would protect it like a cap. They had massive jaws and flat grinding teeth typical of a large herbivore. Its squat skeleton had a variety of features to support the heavy shell, including fused vertebrae and elephant-like short, stout limbs. They went extinct only about 10,000 years ago, possibly having been hunted to oblivion by early Americans. There is even some evidence that people used their empty shells as shelters.
Richard_OwenGlyptodon was formally named as a genus in 1839 by the extraordinary Sir Richard Owen (1804-1892). Owen was a giant of natural history through most of the 19th Century. He is most remembered for inventing the term Dinosauria (“terrible lizards”) and for being on the wrong side of history at the beginning of the Darwinian Revolution. He was apparently ambitious to the point of severity, and very tough on his contemporary scientists. Thomas Henry Huxley, for example, despised Owen for his treatment of his colleagues. Ironically, Huxley did considerable work on further describing Glyptodon in 1865. Owen had vision as well as sharp observational skills. He was a primary force in the eventual establishment of the Natural History Museum in London in 1881. It can be argued that this museum set the high standards of accessibility and research we now expect from all such institutions. Sir Richard Owen is such a large and well known figure I can simply refer you to one of many websites describing Owen’s life and contributions.

This post marks three complete years of Wooster’s Fossil of the Week. That’s 156 posts. You can visit the very first post (about a Devonian tabulate coral) and see how the entries have evolved, so to speak. We still have plenty more fossils to describe!


Gallo, V., Avilla, L.S., Pereira, R.C. and Absolon, B.A. 2013. Distributional patterns of herbivore megamammals during the Late Pleistocene of South America. Anais da Academia Brasileira de Ciências 85(2): 533-546.

Huxley, T.H. 1865. On the osteology of the genus Glyptodon. Philosophical Transactions of the Royal Society of London 155: 31-70.

Oliveira, É.V., Porpino, K.O. and Barreto, A.F. 2010. On the presence of Glyptotherium in the Late Pleistocene of northeastern Brazil, and the status of “Glyptodon” and “Chlamydotherium“. Paleobiogeographic implications. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 258(3): 353-363.

Owen, R. 1839. Description of a tooth and part of the skeleton of the Glyptodon, a large quadruped of the edentate order, to which belongs the tessellated bony armor figured by Mr. Clift in his memoir on the remains of the Megatherium, brought to England by Sir Woodbine Parish. FGS Proceedings of the Geological Society of London 3: 108-113.

Wooster’s Fossils of the Week: Rugose corals from the Upper Ordovician of Ohio

December 22nd, 2013

585px-LibertyFormationSlab092313College of Wooster student Willy Nelson spotted and collected up this beautiful Liberty Formation slab on our 2013 Invertebrate Paleontology course field trip to the Upper Ordovician of the Caesar Creek area in southern Ohio. There are many exquisite fossils on this apparent carbonate hardground (a cemented seafloor), the most prominent of which are the four linked circular corallites in the top center. They are of the species Streptelasma divaricans (Nicholson, 1875), shown in more detail below.

Streptelasma divaricans (Nicholson, 1875) 585Streptelasma divaricans is a rugose coral, a prominent order that dominated the Paleozoic coral world from the Ordovician into the Permian. Unlike most rugose corals, it usually is found attached to some hard surface like a shell, rock or hardground. S. divaricans is relatively rare in the Upper Ordovician of the Cincinnati area compared to its free-living cousin Grewingkia canadensis. In its adult form (as seen here) it can have about 60 septa (vertical partitions radiating from the center), alternating from small to large and often with a twist at the center. In life there would have been a tentacle-bearing polyp sitting in each of these septate cups (corallites) catching tiny prey as it passed by in the water currents. We presume that they lived much like modern corals today. S. divaricans was, by the way, an invading species in this Late Ordovician shallow sea community.

Streptelasma divaricans was named as Palaeophyllum divaricans in 1875 by Henry Alleyne Nicholson (1844-1899). We met Dr. Nicholson in an earlier blogpost. Astonishingly, one of our  geology majors in the paleontology course this semester is Brittany Nicholson, a direct descendant. Way cool.
WillyBrachiopodLepidocyclusperlamellosus092313Another nice fossil on Willy’s slab (in the upper right) is the rhynchonellid brachiopod Lepidocyclus perlamellosus, shown closer above.
WillyBivalve092313The curved, indented line in the middle of the slab (shown above) appears to be the outline of a bivalve shell. The original shell was made of aragonite and thus dissolved away very early (possibly even on the seafloor before burial). There is not enough shape remaining to identify it. The twig-like fossil with tiny holes above the scale is, of course, a trepostome bryozoan. You didn’t need me to tell you that!


Elias, R.J. 1983. Middle and Upper Ordovician solitary rugose corals of the Cincinnati Arch region. United States Geological Survey Professional Paper 1066-N: 1-13.

Elias, R.J. 1989. Extinctions and origins of solitary rugose corals, latest Ordovician to earliest Silurian in North America. Fossil Cnidaria 5: 319-326.

Nicholson, H.A. 1875. Description of the corals of the Silurian and Devonian systems. Ohio Geological Survey Report, v. 2, part 2, p. 181-242.

Patzkowsky, M.E. and Holland, S.M. 2007. Diversity partitioning of a Late Ordovician marine biotic invasion: controls on diversity in regional ecosystems. Paleobiology 33: 295-309.

Wooster’s Fossil of the Week: A trepostome bryozoan from the Upper Ordovician of northern Kentucky

December 15th, 2013

Heterotrypa Corryville 585First, what U.S. state does this delicious little bryozoan resemble? It’s so close I can even pick out Green Bay. This is Heterotrypa frondosa (d’Orbigny, 1850), a trepostome bryozoan from the Corryville Formation (Upper Ordovician) in Covington, Kentucky. I collected it decades ago while exploring field trip sites for future classes. This zoarium (the name for a bryozoan colony’s skeleton) is flattened like a double-sided leaf, hence the specific name referring to a frond. In the view above you can see a series of evenly spaced bumps across the surface termed monticules. A closer view is below.
Heterotrypa closer 585The monticules are composed of zooecia (the skeletal tubes for the individual bryozoan zooids) with slightly thickened walls standing up above the background of regular zooecia. The hypothesized function of these monticules was to make the filter-feeding of the colony more efficient by utilizing passive flow to produce currents and whisk away excurrents from the lophophores (feeding tentacles) like little chimneys. In 1850, Alcide Charles Victor Marie Dessalines d’Orbigny (French, of course) originally named this species Monticulipora frondosa because of the characteristic bumps.
Boring in Heterotrypa 585If you look closely at the zoarium you will see holes cut into it that are larger than the zooecia. A closer view of one is shown above. These are borings called Trypanites, which have appeared in this blog many times. They were cut by some worm-like organism, possibly a filter-feeding polychaete, that was taking advantage of the bryozoan skeleton to make its own home. It would have extended some sort of filtering apparatus outside of the hole and captured organic particles flowing by. It was a parasite in the sense that it is taking up real estate in the bryozoan skeleton that would have been occupied by feeding zooids. It may not have been feeding on the same organic material, though, as the bryozoan. It may have been consuming a larger size fraction than the bryozoan zooids could handle.


Boardman, R.S. and Utgaard, J. 1966. A revision of the Ordovician bryozoan genera Monticulipora, Peronopora, Heterotrypa, and Dekayia. Journal of Paleontology 40: 1082-1108

d’Orbigny, A. D. 1850. Prodro/ne de Paleontologie stratigraphique universelle des animaux mollusques & rayonnes faisant suite au cours elementaire de Paleontologie et de Geologic stratigraphiques, vol. 2. 427 pp. Masson, Paris.

Erickson, J.M. and Waugh, D.A. 2002. Colony morphologies and missed opportunities during the Cincinnatian (Late Ordovician) bryozoan radiation: examples from Heterotrypa frondosa and Monticulipora mammulata. Proceedings of the 12th International Conference of the International Bryozoology Association. Swets and Zeitlinger, Lisse; pp. 101-107..

Kobluk, D.R. and Nemcsok, S. 1982. The macroboring ichnofossil Trypanites in colonies of the Middle Ordovician bryozoan Prasopora: Population behaviour and reaction to environmental influences. Canadian Journal of Earth Sciences 19: 679-688.

Wooster’s Fossil of the Week: Echinoid fragments from the Upper Carboniferous of southern Nevada

December 8th, 2013


Bird Spring Echinoid Carboniferous KC33 585This rock has been in my Invertebrate Paleontology course teaching collection since I arrived in Wooster. I collected it way back when I was doing my fieldwork for my dissertation on the biostratigraphy and paleoecology of the Bird Spring Formation (Carboniferous-Permian). This specimen comes from Kyle Canyon in the Spring Mountains west of Las Vegas, Nevada. It is from the Upper Carboniferous part of the Bird Spring. It is up this week in honor of Jeff Thompson, a new graduate student at the University of Southern California beginning his thesis work on Paleozoic echinoids.

These are spines and test plates from the echinoid Archaeocidaris M’Coy, 1844. There are many far more attractive specimens known of Archaeocidaris, so consider this a more average view of what you’re likely to find in the fossil record. The test plates are polygonal and the spines have characteristic outward-directed thorns on them. This particular specimen was disarticulated after death in a shallow, possibly lagoonal environment.
M'CoyArchaeocidaris was named by Sir Frederick M’Coy, an Irish paleontologist. (You may have seen his name as McCoy or MacCoy, but he signed with the more natively Irish M’Coy.) M’Coy was born in 1817 or 1823 (I’m shocked that there is such a discrepancy in the records) in Dublin (maybe). His father was a physician and a professor at Queen’s College, Galway. M’Coy was apparently an early starter, giving his first paper in 1838 on bird functional morphology and classification. (He was either 15 or 21.) His work history is a bit spotty. In 1841 he became Curator of the Geological Society of Dublin, but was soon replaced. In 1845 he joined the new Geological Survey of Ireland hoping to be a laboratory paleontologist. He ended up doing fieldwork but was rather bad at it, resigning from that job. Off to Cambridge he went to assist Adam Sedgwick in describing fossils. He was at last doing something in which he excelled, resulting in important publications. In 1849 M’Coy was appointed Chair of Geology and Mineralogy at Queen’s College, Belfast. His last career move was a big one: he left Ireland for Australia in 1854 to become one of the first four professors of the new University of Melbourne and director of the National Museum of Victoria (now Museum Victoria). M’Coy was very successful in these roles, although I must note that he was an advocate of importing English rabbits into Australia (you know the result) and he appeared to be a bit of an anti-Darwinist. He died in Melbourne in 1899. (Thank you to my friend Patrick Wyse Jackson for these details on M’Coy.)
Echinocrinus urii pl XXVII 1 M'Coy 1844The above is a figure in M’Coy’s 1844 work of the echinoid Echinocrinus urii (M’Coy, 1844, pl. XXVII, figure 1). There is a long story as to how this E. urii became the type species of Archaeocidaris. Andrew Smith sums it as:

Cidaris urii Fleming, 1828, p. 478, by subsequent designation of Bather 1907, p. 453. Generic name Archaeocidaris validated in Opinion 370 under plenary powers, by suppression under same powers of generic name Echinocrinus Agassiz, 1841. Opinions of the International Commission of Zoological Nomenclature 1955, 11, 301-320.

In any case, you can see how closely this illustration of an Irish fossil resembles our fossiliferous slab from the Spring Mountains. Ireland is far from Nevada now, but in the Carboniferous they were considerably closer.


M’Coy, F. 1844. A synopsis of the characters of the Carboniferous limestone fossils of Ireland. Dublin, Printed at the University Press by M.H. Gill.

Rushton, A. 1979. The real M’Coy. Lethaia 12: 226.

Wilson, M.A. 1985. Conodont biostratigraphy and paleoenvironments at the Mississippian-Pennsylvanian boundary (Carboniferous: Namurian) in the Spring Mountains of southern Nevada. Newsletters on Stratigraphy 14: 69-80.

Wyse Jackson, P.N. and Monaghan, N.T. 1994. Frederick M’Coy: an eminent Victorian palaeontologist and his synopses of Irish palaeontology of 1844 and 1846. Geology Today 10: 231-234.

Wooster’s Fossil of the Week: An encrusted cobble from the Upper Ordovician of Kentucky

December 1st, 2013

Ordovician Kope Encrusted Concretion 111813In 1984 I pulled the above specimen from a muddy ditch during a pouring rain near the confluence of Gunpowder Creek and the Ohio River in Boone County, northern Kentucky. It changed my life.
crinoid bryozoan concretion 111813This limestone cobble eroded out of the Kope Formation, a shale-rich Upper Ordovician unit widely exposed in the tri-state area of Kentucky, Indiana and Ohio. It probably is a burrow-filling, given its somewhat sinuous shape. As you can see in the closer view above, it is encrusted with crinoids (the circular holdfasts) and bryozoans of several types, including the sheet-like form in the upper left and the mass of little calcareous chains spread across the center of the view. There are also simple cylindrical borings called Trypanites scattered about.
OrdovicianEdrio113013There were other cobbles at this site as well, including the one imaged above. It shows an encrusting edrioasteroid (Cystaster stellatus, the disk with the star shape in the middle) and a closer view of those chain-like bryozoans (known as Corynotrypa).
Concretion reverse 111813Significantly, the underside of the cobble pictured at the top of the page is smooth and mostly unencrusted, showing just a few of the Trypanites borings. A closer look, though, would reveal highly-eroded remnants of bryozoans. This means that the cobble sat on the seafloor with its upper surface exposed long enough to collect mature encrusters and borers. It appears, though, that the cobbles were occasionally flipped over, killing the specimens now on the underside and exposing fresh substrate for new encrusters.

How did this cobble change my life? My wife Gloria and I were scouting field trip sites for my Invertebrate Paleontology course. I was a very new professor and needed localities for our upcoming travels. I thought I had seen enough during that wet and chilly day, but Gloria wanted to explore one more outcrop. Fine, I thought, we’ll stop here at this muddy ditch and she’ll be quickly convinced it was time to quit. As I stepped out of the car I saw this cobble immediately. Then we both saw that the ditch was full of them. They showed spectacular encrusting and boring fossils with exquisite preservation, but more importantly they demonstrated a process of ecological succession rarely if ever seen in the paleontological record. It led to two papers the following year that came out just before my first research leave in England. There my new interests in hard substrate organisms led me to my life-long friends and colleagues Paul Taylor and Tim Palmer. Since then we’ve published together dozens of papers on encrusters and borers, now known as sclerobionts, and used them to explore many questions of paleoecology and evolution.

Thank you, Gloria, for one more outcrop!


Taylor, P.D. and Wilson, M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62: 1-103.

Wilson, M.A. 1985a. Disturbance and ecologic succession in an Upper Ordovician cobble-dwelling hardground fauna. Science 228: 575-577.

Wilson, M.A. 1985b. A taxonomic diversity measure for encrusting organisms. Lethaia 18: 166.

Wilson, M.A. and Palmer, T.J. 1992. Hardgrounds and Hardground Faunas. University of Wales, Aberystwyth, Institute of Earth Studies Publications 9: 1-131.

Wooster’s Fossil of the Week: A crinoid calyx from the Lower Carboniferous of Iowa

November 24th, 2013

Macrocrinus verneuilianus (Shumard, 1855) 585In honor of Echinoderm Week for my Invertebrate Paleontology course, we have a beautiful crinoid calyx (or crown, or just “head”) on a slab from the Burlington Limestone (Lower Carboniferous, Osagean) found near Burlington, Iowa. I inherited this fossil when I arrived at Wooster, so I have no idea who collected it or when. The handwritten number is similar to those on many of our 19th century specimens. The sharp features of the specimen have been a bit dulled by a preparation technique that probably involved abrasives.

The crinoid is Macrocrinus verneuilianus (Shumard, 1855) of the Order Monobathrida. It is unusual in that it is preserved with its filter-feeding arms intact, along with a magnificent anal tube (see closer view below).
Macrocrinus anal chimney 585The anal tube, sometimes called an anal chimney, is just what you guessed it would be — an anus at the end of a long pipe of calcitic plates. Its primary purpose was all about hygiene. The tube allowed waste products to be whisked away far from the mouth of the crinoid, which was at the base of the arms. Some researchers suggest that the long tube served another function as well: it may have helped stabilize and direct the filter-feeding fan of outstretched arms in a stiff current, something like the tail of an airplane or a panel on a weather vane.

Macrocrinus verneuilianus (Shumard, 1855) diagramFigure of Macrocrinus verneuilianus (9) from “Paleontology of Missouri” (1884) by Charles Rollin Keyes. That long anal tube is not exaggerated!
Shumard585Benjamin Franklin Shumard (1820-1869) named Macrocrinus verneuilianus in 1855. As you might have deduced from his name, Shumard was a Pennsylvanian, having been born in Lancaster. He received his bachelor’s degree from Miami University in Oxford, Ohio, and then later earned an MD in Louisville, Kentucky, in 1843. As a young doctor in Kentucky, he began to collect fossils as a hobby. After just three years of medicine, he gave it up to pursue a career as a geologist. (Those Kentucky fossils must have been particularly fine!) By 1848 he was on geological surveys for Minnesota, Wisconsin and Iowa, and in 1850 he went on a geological survey expedition to Oregon. (Imagine that trip in 1850.) In 1853 he became the paleontologist in the Missouri Geological Survey. In 1858 he left Missouri to begin the first Geological Survey in Texas. The Civil War must have caused him considerable pain, since he was a Pennsylvanian in Texas. He moved to St. Louis and renewed his medical career in 1861. In 1869, he decided to move south to New Orleans for health reasons. The steamship he took burned to the waterline one evening north of Vicksburg. He was safely rescued, but contracted pneumonia in the process. He returned quickly to St. Louis and there died at 49 years of age. At the time of his death Shumard was president of the St. Louis Academy of Science and a member of the Geological Societies of London, France, and Vienna, and he was also a member of the academies of science in Philadelphia, Cincinnati, and New Orleans. No doubt we would have had much more scientific accomplishment from this young paleontologist had he lived longer.


Ausich, W.I. 1999. Lower Mississippian Burlington Limestone along the Mississippi River Valley in Iowa, Illinois, and Missouri, USA, p. 139-144. In: H. Hess, W.I. Ausich, C.E. Brett and M.J. Simms (eds.), Fossil Crinoids, Cambridge University Press.

Ausich, W.I. and Kammer, T.W. 2010. Generic concepts in the Batocrinidae Wachsmuth and Springer, 1881 (Class Crinoidea). Journal of Paleontology 84: 32-50.

Lane, N.G. 1963. Two new Mississippian camerate (Batocrinidae) crinoid genera. Journal of Paleontology 37: 691-702.

Shumard, B.F. 1855. Description of new species of organic remains. Missouri Geological Survey 2:185–208.

Wooster’s Fossil of the Week: A long scleractinian coral from the Middle Jurassic of Israel

November 17th, 2013

Enallhelia_370_Callovian_Israel_585Just one image for this week’s fossil, but we make up for the numbers in image length! The above fossil with the alternating “saw teeth” is the scleractinian coral Enallhelia d’Orbigny, 1849. It is a rare component of the diverse coral fauna found in the Matmor Formation (Callovian-Oxfordian) in southern Israel. I collected this particular specimen (from locality C/W-370 in Hamakhtesh Hagadol, for the record) during this past summer’s expedition to the Negev. It is preserved remarkably well considering that its original aragonite skeleton has been completely calcitized.

Enallhelia is in the Family Stylinidae, also named by French naturalist Alcide Charles Victor Marie Dessalines d’Orbigny. (Love that name; he was briefly profiled in a previous entry.) There are many species in the genus (at least two dozen), but I can’t figure out which this one is. I’ll need a coral expert because half of the available species look pretty much the same to me. Enallhelia is a dendroid coral, meaning its corallum has tree-like branches, only one of which we see here. Each branch has alternating corallites on each side, which in life would have held the individual tentacular polyps. Each corallite has radial symmetry, not the usual hexameral symmetry as seen in most scleractinians. The genus ranges from the Jurassic into the Cretaceous and is cosmopolitan. Enallhelia is especially well known from Europe, but that may be just a collector effect.

What I like about Enallhelia is that it can be an excellent paleoenvironmental marker. Leinfelder and Nose (1997) show that it is most often found in “marly coral meadows” near storm wavebase on carbonate platforms. This means it is in shallow but quiet waters well within the photic zone most of the time, but may be occasionally disturbed by storm wave currents. This is an accurate description of most of the depositional environment of the Matmor Formation.


Hudson, R.G.S. 1958. The upper Jurassic faunas of southern Israel. Geological Magazine 95: 415-425.

Leinfelder, R.R. and Nose, M. 1997. Upper Jurassic coral communities within siliciclastic settings (Lusitanian Basin, Portugal): Implications for symbiotic and nutrient strategies. Proceedings of the 8th International Coral Reef Symposium 2: 1755-1760.

Olivier, N., Martin-Garin, B., Colombié, C., Cornée, J.-J., Giraud, F., Schnyder, J., Kabbachi, B. and Ezaidi, K. 2012. Ecological succession evidence in an Upper Jurassic coral reef system (Izwarn section, High Atlas, Morocco). Geobios 45: 555-572.

Wooster’s Fossil of the Week: A colonial scleractinian coral from the Pliocene of Cyprus

November 10th, 2013

Cladocora_585This week’s fossil is another from the collection made in 1996 on a Keck Geology Consortium expedition to Cyprus with Steve Dornbos as a Wooster student. Steve and I found a spectacular undescribed coral reef in the Nicosia Formation (Pliocene) near the village of Meniko (N 35° 5.767′, E 33° 8.925′). Finding a reef was a surprise because the unit is mostly quartz silt, which is not a sediment you usually associate with coral reefs. It was an advantage, though, because the silt was poorly lithified and could be easily removed from the fossils. The significance of this reef was that it represents the early recovery of marine faunas following the Messinian Salinity Crisis and the later refilling of the Mediterranean basin (the Zanclean Flood). Steve and I published our observations and analyses of this reef community in 1999.

The coral is a species of the genus Cladocora Ehrenberg, 1834. This genus, a member of the Family Caryophylliidae, ranges from the Late Cretaceous to today, so it is a hardy group. This may be because it is unusually diverse in its habits, ranging from the shallow subtidal down to at least 480 meters, and including both zooxanthellate (containing symbiotic photosynthesizing organisms called zooxanthellae) and azooxanthellate (with no such symbionts) species. Since our fossils lived in shallow water, they were almost certainly zooxanthellate.

(Courtesy of Wikimedia Commons user Esculapio)

(Courtesy of Wikimedia Commons user Esculapio)

Cladocora is still found today in the Mediterranean (see the above Cladocora caespitosa). Like all zooxanthellate scleractinian corals, these shallow species of Cladocora obtain their nutrition from the byproducts of their photosynthetic symbionts and a diet of small animals (mostly arthropods and larvae) they collect with their tentacles. These tentacles are lined with “stinging cells” called nematocysts.
CladocoraSpondylus_585Our Pliocene Cladocora formed the framework of a reef at least six meters high and 50 meters wide. It had many shelled organisms living entwined in the branches of the coral, like the bivalve Spondylus pictured above. You can see the corallites (individual tubes) embedded in the shell.
EhrenbergChristianGottfried_585Christian Gottfried Ehrenberg (1795-1876) named the genus Cladocora from specimens in the Red Sea. He was a German naturalist and explorer who is often credited with founding the field of micropaleontology (the study of microfossils such as foraminiferans, ostracodes and diatoms). He earned an M.D. at the University of Berlin and remained on the university staff for his entire career. He was no homebody, though, traveling as a scientist throughout the Mediterranean and Middle East, Central Asia and Siberia. (His first expedition to the Middle East was an adventure, as you can read at the link.) He was the first to prove that fungi reproduce via spores, to describe the anatomy of corals, and to identify plankton as the source for marine phosphorescence. Ehrenberg was also the first to discover microfossils in rocks, noting that some rocks (like chalk) are made almost entirely of them. His best known books include Reisen in Aegypten, Libyen, Nubien und Dongola (1828; “Travels in Egypt, Libya, Nubia and Dongola”) and Die Infusionsthierchen als volkommene Organismen (1838; “The Infusoria as Complete Organisms”). That last concept (“volkommene Organismen” or “complete organisms”) was his idea that even the smallest organisms had all the working organs of the largest. That one didn’t go so well!


Cowper Reed, F.R. 1935. Notes on the Neogene faunas of Cyprus, III: the Pliocene faunas. Annual Magazine of Natural History 10 (95): 489-524.

Cowper Reed, F.R. 1940. Some additional Pliocene fossils from Cyprus. Annual Magazine of Natural History 11 (6): 293-297.

Dornbos, S.Q. and Wilson, M.A. 1999. Paleoecology of a Pliocene coral reef in Cyprus: Recovery of a marine community from the Messinian Salinity Crisis. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 213: 103-118.

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