Rain delay in Yorkshire. Time for sample management.

June 13th, 2015

Sample management 061315SCARBOROUGH, ENGLAND (June 13, 2015) — Our good fortune with the weather finally ended with a steady downpour this morning. Since it was during an advantageous tide, and I didn’t want us slipping around on wet intertidal boulders at Filey Brigg, we cancelled the day’s fieldwork. As generations of Wooster paleontologists know, this gives us time for Sample Management. We went through all that we collected, washed each fossil in my bathroom sink, and dried the lot on the hotel towels so kindly provided to us. It was the first time I got a good luck at many of the specimens the students collected, so it was rather fun. We then rebagged and labelled everything for the trip back home. Mae and Meredith have put together a nice collection for their studies. We have two more days of fieldwork to finish collecting for Meredith’s project.

Another gorgeous day on the Yorkshire coast

June 10th, 2015

Dismantled pillbox Filey BeachSCARBOROUGH, ENGLAND (June 10, 2015) — We certainly can’t complain about the weather for our fieldwork in Yorkshire this year. Today was spectacular with blue skies and cool sea breezes. It made the long beach hikes very pleasant.

1 Mae on Speeton 061015This was our first day without our English colleague (and Yorkshire native) Paul Taylor, so we were on our own for transportation. We figured out the bus system, though, and made it to the Lower Cretaceous Speeton Clay at Reighton Sands in good time. Here is the last view you’ll have of Mae Kemsley (’16) working on her outcrops of this gray, mushy unit. We collected sediment samples this morning, along with a few last fossils.

2 Meredith on Speeton 061015Here is Meredith Mann (’16) doing the same. We finished all of our fieldwork for Mae’s project by 10:30 a.m., so we could make a long beach hike from the Speeton Cliffs northwards to Filey.

3 Meredith waiting on tide

4 Mae waiting on tideWe hiked as far as we could on Filey Brigg, but had to chill because our sites were still cut off by the high tide. Waiting for a tide to drop is tedious, but the students had plenty of patience.

5 Thalassinoides 061015We reached the large slabs of Hambleton Oolite Member (Upper Jurassic, Oxfordian) with Thalassinoides burrows to begin Meredith’s data collection. These are impressive trace fossils, with numerous shelly fossils in the surrounding matrix. We took reference photos and collected what we could. Unfortunately only three slabs met our criteria for measurements, so we moved to a unit exposed just below the Hambleton.

6 Cannonball concretionsOn the north side of Filey Brigg there are these large “cannonball” concretions, which were excellent stratigraphic markers for us. They are in the Saintoft Member of the Lower Calcareous Grit Formation. They told us that the units above were the Passage Beds Member of the Coralline Oolite Formation.

7 Passage Beds 061015Mae and Meredith are here collected fossils from the Passage Beds above the concretions. This unit is interesting to us because it contains shelly debris that was apparently washed onto shore during storms. These shells are often heavily encrusted with oysters and serpulids. Such sclerobionts have been little studied in this part of the section.

8 MMbus 061015On our sunny ride home the students sat in the front of the top section of our double-decker bus. Not a bad commute for a day’s work!


Return to the Speeton Clay

June 9th, 2015

1 Mae on Speeton 060915SCARBOROUGH, ENGLAND (June 9, 2015) — Team Yorkshire returned to the Speeton Clay today to begin the fieldwork for Mae Kemsley’s Senior Independent Study project. Mae chose to work on the incredible diversity of belemnites found in this Lower Cretaceous unit. There are two aspects to her study: the paleoecology of the belemnites themselves, and the taphonomy of their distinctive bullet-shaped calcitic rostra (guards). We hope that Mae will be able to do some stable isotope work to help elucidate the paleoenvironments these pelagic creatures lived in. Oxygen isotopes in particular may indicate the seawater temperatures when the belemnites were forming their skeletons. The Speeton Clay has faunas from alternating Boreal (northern, colder) and Tethyan (southern) regions, so this will be interesting.

2 Middle Cliff SpeetonHere is the Speeton Clay forming the Middle Cliff along the shoreline. Virtually every outcrop of this unit is slumped from above, so sorting out the stratigraphy is a challenge.

3 Mae working 060915Here is Mae again working through a small patch of the Speeton Clay. There are four broad intervals of the unit (A, B, C, D) that we must recognize by the fossil content and the position of the outcrop relative to various field markers like abandoned pillboxes, breakwaters, and large rocks.5-SS-Laura-boilers

One of our intertidal landmarks is a set of boilers from the 1897 wreck of the SS Laura, an Austro-Hungarian cargo ship that ran aground near Filey Brigg. The heavy boilers have stayed in essentially the same place for over a century.

4 Speeton work 060915The weather could not have been better today. We got Mae’s project off to a fine start with several sets of samples collected from the four primary units of the Speeton Clay.

Paul Taylor returned to his home in Epsom at the end of the day, leaving the three Americans to their own devices. He was essential in our first week, getting us oriented to the local geology, expertly driving us around to the various sites, and entertaining us with his trademark puns. He trained us well to carry on into week two of the Yorkshire Expedition.

Speeton Cliffs and Filey Brigg on a fine English summer day

June 7th, 2015

1 Speeton 060715SCARBOROUGH, ENGLAND (June 7, 2015) — This steep and muddy slope may not look like much, but it is the man exposure of the famous Speeton Clay, a Lower Cretaceous unit rich with fossils. Team Yorkshire started here (N 54.16654°, W 00.24567°) this morning to continue our reconnaissance of the local geology. The weather could not have been better. (I can only imagine what this sediment is like when wet!)

2 Slumped Speeton Pillbox 060715The Speeton Clay is quite mobile, with slips and land slippages very common along its coastal exposure. This is a World War II pillbox, part of the sea defenses of Britain, making its way down slope on the clay. On the shore itself are bits of previous WWII concrete installations that are now on the beach.

3 Red ChalkAfter collecting dozens of belemnites from the Speeton Clay for future research, we visited an exposure of the Red Chalk (Hunstanton Formation), which has smaller belemnites of a different genus.

4 Chalk cliffs s SpeetonIf we continued to the south we would have met these imposing cliffs of chalk, the northern part of the series of white coastal chalks that extends south past Dover. Seabirds swirled around them in the thousands this morning.

5 Paul marine tutorialWhile walking back to our car, Paul Taylor showed Meredith Mann and Mae Kemsley various intertidal organisms exposed on the broad beach beneath the Speeton Cliffs.

6 Barnacle covered boulder SpeetonAt a certain mid-tide level, the boulders on the beach were entirely covered with tiny barnacles. The rock itself is completely hidden.

7 Barnacles limpets SpeetonHere is a closer view of the rock surface. The oldest barnacles are greenish, the younger are gray. You can easily see several small limpets, but do you see the three large individuals in the center? They are camouflaged by their covering of barnacles.

8 Speeton cliffs beachFor a Sunday afternoon on such a nice day, we were pleased to see very few people on large stretches of the beach along the Speeton Cliffs. We had much more company later in the day.

9 Hambleton oolite south 060715In the afternoon we visited Filey Brigg for a look at parts of the Coralline Oolite Formation (Upper Jurassic, Oxfordian; N 54.21674°, W 00.26922°). We found the Hambleton Oolite Member very accessible and with a good number of fossils that could be collected. We are here looking at the “Upper Leaf” of the unit.

10 Thalassinoides sediment 060715Down on the Brigg itself we saw these massive overturned boulders of the Birdsall Calcareous Grit Member with spectacular examples of the trace fossil “boxwork” Thalassinoides. These fossil burrow systems were made by shrimp, probably of the callianassid variety.

11 Thalassinoides full relief 060715Sometimes the sediment between the infilled Thalassinoides tunnels was washed away, leaving this beautiful network in full relief.

12 Hambleton Oolite north 060715On the north side of Filey Brigg we could continue to follow the Upper Leaf of the Hambleton Oolite Member. The exposure is very good and well above the high tide. The access to this place, though, requires a low tide like we had this afternoon.

13 Hambleton Oolite Lower Leaf 060715At this site on the north side of Filey Brigg (N 54.21823°, W 00.26908°) we can get to the Lower Leaf of the Hambleton Oolite Member, with the Birdsall Calcareous Grit Member just above. Again, the Hambleton has many fossils that can be collected. If you look at the undersurface of the yellowish rock above our field party, you may be able to make out the Thalassinoides trace fossils. We can thus place the loose blocks with this distinctive trace fossil in their original stratigraphic position.

Another delightful field day. One more expedition tomorrow, and then we decide on the specific student projects.


Wooster’s Fossil of the Week: A Cretaceous oyster with borings and bryozoans from Mississippi

December 26th, 2014

Exogyra costata Prairie Bluff Fm Maastrichtian 585
As winter closes in on Ohio, I start dreaming about past field trips in warm places. This week’s fossil takes me back to fieldwork in Alabama and Mississippi during May of 2010. Paul Taylor (The Natural History Museum, London) and I studied the Upper Cretaceous and Lower Paleogene sections there with our students Caroline Sogot and Megan Innis (Wooster ’11). We had a most excellent and productive time.

The above fossil was very common in our Maastrichtian (Upper Cretaceous) outcrops. It is a left valve of Exogyra costata Say, 1820, from the Prairie Bluff Chalk Formation exposed in Starkville, Mississippi (locality C/W-395). It is a large oyster with a very thick calcitic shell. It has a distinctive spiral, making it look a bit like a snail. Oysters are sessile benthic filter-feeders that usually sit on their large left valves with a flatter and smaller right valve on top. Exogyra stayed stable on the seafloor because of its massive weight.
Interior left 111914This is a view of the inside of the left valve at the top of this entry. You can see the large, dark adductor muscle scar in the center. (The adductors closed the valves.) Note the many evenly-spaced holes in the oyster shell interior, with a closer view below.
Entobia 111914These holes were excavated by a clionaid sponge, producing the trace fossil Entobia. The sponge used the oyster shell as a protective substrate. It infested the valve after the death of the oyster made that particular piece of hard real estate available.
Interior close view 111914In the very center are some tiny encrusting cyclostome cheilostome bryozoans. Caroline, Paul and Liz Harper studied encrusting bryozoans like these from this field area as part of biogeographical and paleoecological investigation of the Cretaceous extinctions (see Sogot et al., 2013). I imagine Paul can even identify this species shown here. I wouldn’t dare! [Update from Paul: “I think these examples are cheilostomes, quite possibly Tricephalopora …” See comments.]
Thomas_Say_1818The genus Exogyra, along with the species E. costata, was named by Thomas Say (1787-1834) in 1820 (pictured above in 1818). Say was a brilliant American natural historian. Among his many accomplishments in his short career, in 1812 he helped found the Academy of Natural Sciences of Philadelphia, the oldest natural science research institution and museum in the New World. He is best known for his descriptive entomology in the new United States, becoming one of the country’s best known taxonomists. He was the zoologist on two famous expeditions led by Major Stephen Harriman Long. The first, in 1819-1820, was to the Great Plains and Rocky Mountains; the other (in 1823) was to the headwaters of the Mississippi. Along with his passion for insects, Say also studied mollusk shells, both recent and fossil. He was a bit of an ascetic, moving to the utopian socialist New Harmony Settlement in Indiana for the last eight years of his life. It is said his simple habits and refusal to earn money caused problems for his family. Say succumbed to what appeared to by typhoid fever when he was just 47.


Harris, G.D. 1896. A reprint of the paleontological writings of Thomas Say. Bulletins of American Paleontology, v. 1, number 5, 84 pp.

Say, T.G., 1820. Observations on some species of Zoophytes, shells, etc., principally fossils. American Journal of Science, 1st series, vol. 2, p. 34-45.

Sogot, C.E., Harper, E.M. and Taylor, P.D. 2013. Biogeographical and ecological patterns in bryozoans across the Cretaceous-Paleogene boundary: Implications for the phytoplankton collapse hypothesis. Geology 41, 631-634.

Wooster’s Fossils of the Week: Bivalve borings, bioclaustrations and symbiosis in corals from the Upper Cretaceous (Cenomanian) of southern Israel

October 17th, 2014

Fig. 2 Aspidiscus1bw_scale 585The stark black-and-white of these images are a clue that the fossil this week has been described in a paper. Above is the scleractinian coral Aspidiscus cristatus (Lamarck, 1801) from the En Yorqe’am Formation (Cenomanian, Upper Cretaceous) of southern Israel. The holes are developed by and around tiny bivalves and given the trace fossil name Gastrochaenolites ampullatus Kelly and Bromley, 1984. This specimen was collected during my April trip to Israel, a day recorded in this blog. I crowd-sourced the identification of these corals, and they were highlighted as earlier Fossils of the Week. Now I’d like to describe them again with new information, and celebrate the publication of a paper about them.

En Yorqe'am040914aThis is the exposure of the En Yorqe’am Formation where Yoav Avni and I collected the coral specimens approximately 20 meters from its base in Nahal Neqarot, southern Israel (30.65788°, E 35.08764°). It is an amazingly fossiliferous unit here with brachiopods, stromatoporoid sponges, zillions of oysters, gastropods, ammonites and the corals.

The abstract of the Wilson et al. (2014) paper tells the story: “Specimens of the small compound coral Aspidiscus cristatus (Lamarck, 1801) containing evidence of symbiosis with bivalves have been found in the En Yorqe’am Formation (Upper Cretaceous, early Cenomanian) of southern Israel. The corals have paired holes on their upper surfaces leading to a common chamber below, forming the trace fossil Gastrochaenolites ampullatus Kelly and Bromley, 1984. Apparently gastrochaenid bivalve larvae settled on living coral surfaces and began to bore into the underlying aragonitic skeletons. The corals added new skeleton around the paired siphonal tubes of the invading bivalves, eventually producing crypts that were borings at their bases and bioclaustrations at their openings. When a boring bivalve died its crypt was closed by the growing coral, entombing the bivalve shell in place. This is early evidence of a symbiotic relationship between scleractinian corals and boring bivalves (parasitism in this case), and the earliest record of bivalve infestation of a member of the Suborder Microsolenina. It is also the earliest occurrence of G. ampullatus.”

Fig. 3 BoringPair2bw_scale 585 Paired apertures of Gastrochaenolites ampullatus in the coral Aspidiscus cristatus.

Fig. 4 EmbeddedBivalve1bw_scale_rev 585Polished cross-section through a specimen of Gastrochaenolites ampullatus in an Aspidiscus cristatus coral. In the lower left of the chamber are layered carbonates (A) representing boring linings produced by the bivalve. An articulated bivalve shell (B) is preserved in the chamber. The chamber has been roofed over by coral growth (C).

Thank you very much to Tim Palmer and Olev Vinn for their critical roles in this paper, and, of course, thanks to Yoav Avni, the best field geologist I know.


Avnimelech, M. 1947. A new species of Aspidiscus from the Middle Cretaceous of Sinai and remarks on this genus in general. Eclogae geologicae Helvetiae 40: 294-298.

Gill, G.A. and Lafuste, J.G. 1987. Structure, repartition et signification paleogeographique d’Aspidiscus, hexacoralliaire cenomanien de la Tethys. Bulletin de la Societe Geologique de France 3: 921-934.

Kleemann, K., 1994. Associations of corals and boring bivalves since the Late Cretaceous. Facies 31, 131-140.

Morton, B. 1990. Corals and their bivalve borers: the evolution of a symbiosis. In: Morton, B. (Ed.), The Bivalvia: Proceedings of a Memorial Symposium in Honour of Sir Charles Maurice Yonge (1899-1986) at the 9th International Malacological Congress, 1986, Edinburgh, Scotland, UK. Hong Kong University Press, Hong Kong, pp. 11-46

Pandey, D.K., Fürsich, F.T., Gameil, M. and Ayoub-Hannaa, W.S. 2011. Aspidiscus cristatus (Lamarck) from the Cenomanian sediments of Wadi Quseib, east Sinai, Egypt. Journal of the Paleontological Society of India 56: 29-37.

Wilson, M.A., Vinn, O. and Palmer, T.J. 2014. Bivalve borings, bioclaustrations and symbiosis in corals from the Upper Cretaceous (Cenomanian) of southern Israel. Palaeogeography, Palaeoclimatology, Palaeoecology 414: 243-245.


Wooster’s Fossils of the Week: Remanié fossils in the Lower Cretaceous of south-central England

August 22nd, 2014

Faringdon ammonite smThe last two editions were about a bryozoan and borings from the Faringdon Sponge Gravels (Lower Cretaceous, Upper Aptian) of south-central England. This week we have some Jurassic fossils from the same unit. That sounds a bit daft at first — Jurassic fossils in a Cretaceous unit? — until it becomes obvious that these are older fossils reworked into a younger deposit. In this case underlying Jurassic ammonites have been unearthed and tossed around with sediment in Cretaceous high-energy tidal channels. These older fossils in a younger context are called remanié, meaning they have been “rehandled” in a fancy French way.

The above image is an example of remanié in the Faringdon Sponge Gravels. It is a partial internal mold of a Jurassic ammonite. Drilled into it are several holes attributed to Early Cretaceous bivalves and called by the trace fossil name Gastrochaenolites. The ammonite fossil was eroded out of an outcrop of Jurassic rock and then bored while rolling around in what would become the Faringdon Sponge Gravels.
Ammonite frag 2 072014This is another Jurassic ammonite internal mold. The jagged lines are the sutures of the ammonite (remnants of the septal walls). This mold was phosphatized (partially replaced with phosphate) before it was reworked into the Cretaceous gravels. Many remanié fossils are phosphatized because of long exposure on the seafloor.
Ammonite frag 1 072014Finally, this is a fragment of another Jurassic ammonite internal mold in the Faringdon Sponge Gravels. It has an odd shape because it has disarticulated along the sutures. We are looking at the face of one of the septa, or at least where this septum would have been if it hadn’t dissolved. You can see some tiny borings that were made by Cretaceous polychaete worms.

In one of the cobbles in the Faringdon Sponge Gravels I found an identifiable ammonite. It was Prorasenia bowerbanki, which indicated that the cobble was derived from the Lower Kimmeridge Clay or Upper Oxfordian clays. The above ammonites are likely from the same Jurassic sequence. This means these fossils were roughly 45 million years old when they were reworked into the sponge gravels. Today it would be as if Eocene fossils were eroding out of a cliff and being incorporated within a modern sediment. When you think about it, this is a relatively common occurrence.


Murray-Wallace, C V. and Belperio, A.P. 1994. Identification of remanié fossils using amino acid racemisation. Alcheringa 18: 219-227.

Pitt L.J. and Taylor P.D. 1990. Cretaceous Bryozoa from the Faringdon Sponge Gravel (Aptian) of Oxfordshire. Bulletin of the British Museum (Natural History), Geology Series, 46: 61–152.

Wells, M.R., Allison, P.A., Piggott, M.D., Hampson, G.J., Pain, C.C. and Gorman, G.J. 2010. Tidal modeling of an ancient tide-dominated seaway, part 2: the Aptian Lower Greensand Seaway of Northwest Europe. Journal of Sedimentary Research 80: 411-439.

Wilson, M.A. 1986. Coelobites and spatial refuges in a Lower Cretaceous cobble-dwelling hardground fauna. Palaeontology 29: 691-703.

Wooster’s Fossils of the Week: Abundant borings in Early Cretaceous cobbles from south-central England

August 15th, 2014

Faringdon cobble in matrix 071714Last week I described a cyclostome bryozoan on the outside of a quartz cobble from the Faringdon Sponge Gravels (Lower Cretaceous, Upper Aptian) of south-central England near the town of Faringdon. This week I’m featuring a variety of heavily-bored calcareous cobbles from the same unit. One is shown above in its matrix of coarse gravel. The holes are bivalve borings known as Gastrochaenolites. As a reminder, these gravels are very fossiliferous and were deposited in deep channels under considerable tidal current influence (see Wells et al., 2010).

Faringdon cobble 1 071714The large and medium-sized flask-shaped borings are all Gastrochaenolites. In the suite of cobbles described in Wilson (1986), there are three ichnospecies of bivalve borings: G. lapidicus, G. cluniformis and G. turbinatus. It is thus likely, although not necessarily, an indication that at least three bivalve species were boring the soft calcareous claystone to make secure homes for their filter-feeding. The thin, worm-like borings are Maeandropolydora, which were probably made by polychaete “worms”.

Faringdon cobble 3 071714Some of the Gastrochaenolites lapidicus borings have remarkably spherical chambers, a testament to the uniform lithological character of the rock.

Faringdon cobble 5 071714Occasionally bivalve shells are found still preserved in their crypts, along with nestling brachiopods. Some shell bits are visible in the borings above.

FaringdonCobble 585 071714Some of the cobbles are so heavily bored that they fall apart quickly on removal from the matrix. On the Cretaceous seafloor this intensity of boring must have reduced many cobbles to bits before burial — a classic example of bioerosion.

Diagram 071714What is very cool about these Faringdon cobbles is that the borings often overlapped inside, creating a network of tunnels and small cavities that hosted dozens of bryozoan, foraminiferan, sponge, annelid worm, and brachiopod species. This is a diagram from Wilson (1986) showing the combination of external encrusters in a high energy, abrasive world, and coelobites (cavity dwellers) in the protected enclosures. A diverse community can be found on each cobble, inside and out. In a future post I will describe some of these coelobite fossils.


Pitt L.J. and Taylor P.D. 1990. Cretaceous Bryozoa from the Faringdon Sponge Gravel (Aptian) of Oxfordshire. Bulletin of the British Museum (Natural History), Geology Series, 46: 61–152.

Wells, M.R., Allison, P.A., Piggott, M.D., Hampson, G.J., Pain, C.C. and Gorman, G.J. 2010. Tidal modeling of an ancient tide-dominated seaway, part 2: the Aptian Lower Greensand Seaway of Northwest Europe. Journal of Sedimentary Research 80: 411-439.

Wilson, M.A. 1986. Coelobites and spatial refuges in a Lower Cretaceous cobble-dwelling hardground fauna. Palaeontology 29: 691-703.

Wooster’s Fossil of the Week: An Early Cretaceous cobble-dwelling bryozoan

August 8th, 2014

Faringdon quartz 071714One of my formative experiences as a young paleontologist was working in the Faringdon Sponge Gravels (Lower Cretaceous, Upper Aptian) of south-central England while on my first research leave in 1985. (I was just a kid!) These gravels are extraordinarily fossiliferous with sponges, brachiopods, corals, vertebrate bones, and a variety of cobbles, both calcareous and siliceous. These coarse sediments were deposited in narrow channels dominated by tidal currents with significant energy reworking and sorting the fossil and rock debris. Above is a cobble of very hard vein quartz from the Sponge Gravels. On the left end you see an encrusting bryozoan with an unusual morphology.
LhwydThe fossils of the Faringdon Sponge Gravels have been studied for a very long time. The first formal notice of them is a museum catalogue compiled by Edward Lhwyd (image above) and published in 1699. Lhwyd (1660-1709) was a Welsh natural philosopher better known by his Latinized name Eduardus Luidus. He had an unfortunate childhood being the illegitimate son of what has been reported as a “dissolute and impractical” (and poor) father. Still, he was better off than most and had schooling all the way up to Oxford (but he could not afford to graduate). In 1684 he became an assistant to Robert Plot, the Keeper of the Ashmolean Museum in Oxford. He became a great scientific traveler and collector, specializing in plants and fossils and (eventually) ancient languages of Britain. In 1691 he was appointed Keeper at the Ashmolean. His book detailing fossils of Britain (Lithophylacii Britannici Ichnographia) was published with financial assistant from his good friend Isaac Newton.
Corynella in Lhwyd plate 18This is plate 18 from Lhwyd (1699). The fossil in the upper right is the sponge Corynella from the Faringdon Sponge Gravels.

Lhwyd’s views on the origin of fossils are with describing. This is a summary from Edmonds (1973, p. 307-308):

He suggested a sequence in which mists and vapours over the sea were impregnated with the ‘seed’ of marine animals. These were raised and carried for considerable distances before they descended over land in rain and fog. The ‘invisible animacula’ then penetrated deep into the earth and there germinated; and in this way complete replicas of sea organisms, or sometimes only parts of individuals, were reproduced in stone. Lhwyd also suggests that fossil plants known to him only as resembling leaves of ferns and mosses which have minute ‘seed’, were formed in the same manner. He claimed that this theory explained a number of features about fossils in a satisfactory manner: the presence in England of nautiluses and exotic shells which were no longer found in neighbouring seas; the absence of birds and viviparous animals not found by Lhwyd as fossils; the varying and often quite large size of the forms, not usual in present oceans; and the variation in preservation from perfect replica to vague representation, which was thought to represent degeneration with time.

What is most interesting about these ideas is that they have no reference to Noah’s Flood or other divine interventions.

In 1708, Lhwyd was elected a Fellow of the Royal Society in 1708. He didn’t enjoy this privilege long for he died of pleurisy the next year at age 49.
Reptoclausa hagenowi Cretaceous England 071714Now back to the bryozoan on the Faringdon cobble. It is the cyclostome Reptoclausa hagenowi (Sharpe, 1854). It has an odd form of irregularly radiating ridges of feeding zooids (autozooids) separated from each other by structural zooids (kenozooids). I like to think (although I have no evidence) that this morphology was resistant to abrasion in the rough-and-tumble life of living on a cobble in a high-energy channel. There are few other encrusters on the outer surfaces of the Faringdon cobbles.

The next two Fossils of the Week will also be from the fascinating Faringdon Sponge Gravels.


Edmonds, J.M. 1973. Lhwyd, Edward, p. 307-308. In: Gillespie, C.C. (ed.). Dictionary of Scientific Biography, 8. Charles Scribner’s Sons, New York, 620 pp.

Lhwyd, E. 1699. Lithophylacii Britannici Ichnographia. London, 139 pages.

Meyer, C.J.A. 1864. I. Notes on Brachiopoda from the Pebble-bed of the Lower Greensand of Surrey; with Descriptions of the New Species, and Remarks on the Correlation of the Greensand Beds of Kent, Surrey, and Berks, and of the Farringdon Sponge-gravel and the Tourtia of Belgium. Geological Magazine 1(06): 249-257.

Pitt L.J. and Taylor P.D. 1990. Cretaceous Bryozoa from the Faringdon Sponge Gravel (Aptian) of Oxfordshire. Bulletin of the British Museum (Natural History), Geology Series, 46: 61–152.

Wells, M.R., Allison, P.A., Piggott, M.D., Hampson, G.J., Pain, C.C. and Gorman, G.J. 2010. Tidal modeling of an ancient tide-dominated seaway, part 2: the Aptian Lower Greensand Seaway of Northwest Europe. Journal of Sedimentary Research 80: 411-439.

Wilson, M.A. 1986. Coelobites and spatial refuges in a Lower Cretaceous cobble-dwelling hardground fauna. Palaeontology 29: 691-703.

Wooster’s Fossil of the Week: A fragment of an asteroid (the sea star kind) from the Upper Cretaceous of Israel

June 8th, 2014

zichor asteroid aboral 585This is not an important fossil — there is not enough preserved to put a name on it beyond Family Goniasteridae Forbes, 1841 (thanks, Dan Blake) — but it was a fun one to find. It also photographs well. This is a ray fragment of an asteroid (from the group commonly known as the sea stars or starfish) I picked up from the top meter of the Zichor Formation (Coniacian, Upper Cretaceous) in southern Israel (Locality C/W-051) on my field trip there in April 2014. We are looking at the aboral (or top) surface; below is the oral view.
zichor asteroid oral surface 585In this oral perspective you can see a group of tiny, jumbled plates running down the center. This is the ambulacrum, which in life had a row of tube feet extending out for locomotion and grasping prey.
asteroid 2004Above is a sea star held by my son Ted on Long Island, The Bahamas, back in 2004. You can see a bit of resemblance between this modern species and the Cretaceous fossil, mainly the  large knobby ossicles running down the periphery of the rays.

The asteroids have a poor fossil record, at least when compared to other echinoderms like crinoids and echinoids. It appears that all post-Paleozoic asteroids derive from a single ancestral group that squeaked through the Permian extinctions (Gale, 2013). There is a significant debate about the evolution of the asteroids (see Blake and Mah, 2014, for the latest). Unfortunately our little critter is not going to help much in its resolution.

Recently it has been discovered that some living asteroids have microlenses in their ossicles to provide a kind of all-surface photoreception ability. Gorzelak et al. (2014) have found evidence that some Cretaceous asteroids had similar photoreceptors. Maybe our fossil goniasterid fragment could yield this kind of secret property with closer examination.


Blake, D.B. and Mah, C.L. 2014. Comments on “The phylogeny of post-Palaeozoic Asteroidea (Neoasteroidea, Echinodermata)” by AS Gale and perspectives on the systematics of the Asteroidea. Zootaxa 3779: 177-194.

Gale, A.S. 2011. The phylogeny of post-Paleozoic Asteroidea (Neoasteroidea, Echinodermata). Special Papers in Palaeontology 38, 112 pp.

Gale, A.S. 2013. Phylogeny of the Asteroidea, p. 3-14. In: Lawrence, J.M. (ed.), Starfish: Biology and Ecology of the Asteroidea. The Johns Hopkins University Press, Baltimore.

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