Team Dorset arrives in England

June 5th, 2016

1 Temple Meads StationIlminster, Somerset, England — Little Team Dorset, consisting of Cassidy Jester (’17) and me, arrived today in England after a long journey of cars, planes and trains. As you can see from the above image of the Bristol Temple Meads train station, we have brilliant weather. Cassidy and I are here to do the fieldwork for her Independent Study project in the Inferior Oolite (Jurassic, Bajocian) of inland Dorset. We met Tim Palmer at the train station and then drove into Somerset for the afternoon and evening. Tim Palmer and I explored the Inferior Oolite and other units in this region last year to prepare for this expedition.

2 Hinton Blewett St MargaretIf you know anything about Tim Palmer, you know we’re going to examine building stones every chance we get. This is an ideal introduction to our project because of its combination of geology and history. Tim is a master of this topic, especially Jurassic stones. We first stopped in the little parish of Hinton Blewett to examine a Medieval baptismal font in the 13th century Church of St. Margaret (above).

3 Hinton Blewett font and TimHere is Tim examining the baptismal font, looking closely at the stonework.

4 Hinton Blewett font 585The font is made of Dundry Stone, from the top of the Inferior Oolite, with the exception of a later addition of an oolitic limestone cylinder in the stem, apparently to raise it a bit higher. The basin is lined with hammered lead.

5 St Margaret stone Hinton BlewettThe oldest stone in the structure of the church itself is also a Jurassic limestone. It shows these distinctive patterns of iron-rich layers.

6 Wells Cathedral frontWe next visited Wells and its magnificent cathedral. This is the first time I’ve been here. It is spectacular, especially in the brilliant sunlight. It is made mostly of Doulting Stone, a local limestone Tim and I studied last year.

7 Wells top detail 585The front of Wells Cathedral has dozens of Medieval statues, most still well preserved. Christ and the apostles make up the first two rows, followed by English bishops.

8 Wells detailMost of the statues are protected within stone niches.

9 Wells ClockUnusual for English cathedrals, there is a large clock with animated figures that ring bells. This is a feature more common in continental Europe.

10 Purbeck Carboniferous DoultingThis beautiful detail shows a pillar of Purbeck Marble, topped with a disk of dark Carboniferous limestone, and then the Doulting stone.

11 Vicars' Close 585We then visited the famous Vicar’s Close near Wells Cathedral, which is the oldest preserved residential street in Europe. The houses were built in the 14th and earl 15th century.

Tim, Cassidy and I then drove to Ilminster for a night in a Travelodge before fieldwork begins tomorrow. We had an excellent day.


Wooster’s Fossil of the Week: A terebratulid brachiopod from the Middle Jurassic of northwestern France

April 29th, 2016

1 Cererithyris arkelli Almeras 1970 dorsal 585We have another beautiful brachiopod this week from our friend Mr. Clive Champion in England. He sent me a surprise package of fossils earlier this year. They are very much appreciated by me and my students!

The specimen above is Cererithyris arkelli Almeras, 1970, from the Bathonian (Middle Jurassic) of Ranville, Calvados, France. (Ranville, by the way, was the first village liberated in France on D-Day.) It is a terebratulid brachiopod, which we have seen before on this blog from the Miocene of Spain and the Triassic of Israel. They have the classic brachiopod form. The image above shows the dorsal valve with the posterior of the ventral valve housing the round hole for the fleshy stalk (pedicle) it had in life.
2 Cererithyris arkelli Almeras 1970 sideThis is a side view of C. arkelli. The dorsal valve is on the top; the ventral valve on the bottom. It is from this perspective that brachiopods were called “lamp shells” because they resemble Roman oil lamps.
3 Cererithyris arkelli Almeras 1970 ventralThis is the ventral view of the specimen. These brachiopods are remarkably smooth.
4 William_Joscelyn_ArkellCererithyris arkelli was named by Almeras (1970) in honor of William Joscelyn Arkell (1904–1958). Arkell was an English geologist who essentially became Dr. Jurassic during the middle part of the 20th Century. I’m shocked to see that with all his publications, awards and accomplishments, he died when he was only 54 years old.

W.J. Arkell grew up in Wiltshire, the seventh child of a wealthy father (a partner in the family-owned Arkell’s Brewery) and artist mother (Laura Jane Arkell). He enjoyed nature as a child, winning essay contests on his observations of natural history in his native county and south on the Dorset coast. Arkell was unusually tall for his age (6 feet 4.5 inches by age 17.5 years in an unusually detailed note) and was considered to have “outgrown his strength”. Nature and writing were escapes from athletic events. He also published poems.

Arkell attended New College, Oxford University, intending to become an entomologist, but Julian Huxley was his tutor and he quickly adopted geology and paleontology. Eventually he earned a PhD at Oxford in 1928, concentrating his research on Corallian (Upper Jurassic) bivalves of England. As a side project, he published work on Paleolithic human skeletons from northern Egypt.

Oxford suited Arkell, so he stayed there as a research fellow, expanding his research to the entire Jurassic System of Great Britain, then Europe, and then the world. His work became the standard for understanding Jurassic geology and paleontology for decades.

After World War II (in which he served in the Ministry of Transport), Arkell took a senior research position at Trinity College and the Sedgwick Museum, Cambridge University, continuing his work on the Jurassic. He travelled often, including long stints in the Middle East. His health was never good, though, and he had a stroke in 1956, and died after a second stroke in 1958.

During his career Arkell received the Mary Clark Thompson Medal from the National Academy of Sciences in the USA, a Fellowship in the Royal Society, the Lyell Medal from the Geological Society of London, and the Leopold von Buch medal from the German Geological Society.


Almeras, Y. 1970. Les Terebratulidae du Dogger dans le Mâconnais, le Mont dʼOr lyonnais et le Jura méridional. Étude systématique et biostratigraphique. Rapports avec la paléoécologie. Documents des Laboratoires de Géologie Lyon, 39, 3 vol.: 1-690.

Arkell, W.J. 1956. Jurassic Geology of the World. New York; Edinburgh: Hafner Publishing Co; Oliver & Boyd; 806 pp.

Cox, L.R. 1958. William Joscelyn Arkell 1904-1958. Biographical Memoirs of Fellows of the Royal Society 4: 1.

Rousselle, L. and Chavanon, S. 1981. Le genre Cererithyris (Brachiopodes, Terebratulidae) dans le Bajocien supérieur et le Bathonien des Hauts-Plateaux du Maroc oriental. CR somm. Soc. Géol France, 1981: 89-92.

Last day of fieldwork in Israel: More Jurassic enjoyment

March 20th, 2016

1 SU66 at Meredith 032016MITZPE RAMON, ISRAEL — For my last day of fieldwork during this short Spring Break trip to Israel, I returned to Makhtesh Gadol to collect a bit more data from subunits 65 and 66 of the Matmor Formation (Middle Jurassic, Callovian). The above image shows part of my field site in the Meredith section north of the “British Road” across the top of the makhtesh. The yellowish marls are subunit 66, with the white limestone of subunit 65 peeking out at their base. The Matmor Formation is distinguished by this alternation of carbonates and marls, and the faunas in each sediment type are very different.

2 SU65 bivalve at Meredith 032016I did not do any collecting today. Most of my work was tracing rock units, photographing fossils, and taking lots of notes. Above is a nice bivalve in the limestone of subunit 65.

3 SU65 bivalve and bullet 032016Here’s another bivalve with a spent bullet for scale. (Dramatic effect. There is far less ordnance in Makhtesh Gadol than other places I’ve worked in the Negev.) Note that the bivalve is articulated (both valves are locked together), meaning it likely was buried alive. Almost all the bivalves in subunit 65 are articulated.

4 SU65 branching coral 032016There is one horizon in subunit 65 with a surprising number of branching corals. These look very much like the modern Acropora, but they’re not.

5 SU65 SU66 boundary at Meredith 032016This is again the boundary between the white and resistant subunit 65 and the yellowish and nonresistant subunit 66. I have no images of fossils to show you from subunit 66 because they weren’t very photogenic. They are relatively rare and consist mostly of small solitary and colonial corals and occasional oysters.

Thus ends my 2016 fieldwork in Israel! I learned a lot in these eight days of exploration and study, and I worked with excellent colleagues. I have some ideas now for a project that will place these Middle Jurassic rocks and fossils in a global paleobiogeographic and evolutionary context. Many future Independent Study projects are possible!

At some point you must start collecting data

March 18th, 2016

1 Acacia at Meredith SectionMITZPE RAMON, ISRAEL — Today my friend Yoav Avni (Geological Survey of Israel) and I returned to Makhtesh Gadol to pursue a project with Subunit 65 of the Matmor Formation (Callovian, Middle Jurassic). You may recall this limestone contains an extraordinary bedding plane of fossils preserved in near-life positions (as seen in a recent Fossil of the Week entry). Yoav’s job was to find additional exposures of this subunit in the area; mine was to map the distribution of fossils on the bedding plane. This area of the makhtesh, by the way, is called “Meredith’s Section” after IS student Meredith Sharpe, who did splendid work here. The acacia tree above is our traditional lunch spot (when the camels aren’t using it).

2 SU65 bedding plane 031816This is the bedding plane of Subunit 65. I went over every square centimeter of it photographically mapping and detailing it with a square-meter quadrat. It was hot work, and a bit of drudgery compared to the previous days of exploring new exposures.

3 SU65 quadrat 031816This is a typical quadrat, complete with my boot toes. I took 41 quadrat photos like this, and then detailed the fossils within and their positions. In the meantime, Yoav wandered the hills and found many excellent exposures of the same unit, although none with a bedding plane like this. We will be able to compare the fossils in the “traditional” exposures with what we see here.

That’s pretty much it for my day in the desert!

Wooster’s Fossils of the Week: A Jurassic seafloor assemblage

March 18th, 2016

1 DSC_0184 copyImages from fieldwork this week. These are all fossils exposed on a single bedding plane in the Matmor Formation (Middle Jurassic, Callovian) exposed in Makhtesh Gadol. I found them many years ago while working through the stratigraphy near the top of the formation. They present a vignette of life in a shallow carbonate Jurassic sea. They are so well preserved you can almost feel the gentle waves and hear the squawks of the pterosaurs wheeling above. In the top image we have my favorite of the set: A gastropod shell in the middle surrounded by mytilid bivalves. The bivalves were no doubt attached to the gastropod by their thin byssal threads, holding them in place in the choppy waters. The preservation is remarkable. All these shells are calcitized, but retain their ornamentation. They are exposed on a bank of a wadi, and so they have been lightly etched from the matrix by sandy water during floods.

2 DSC_0180 copyJust to show the gastropod-bivalve association is not a fluke of preservation, here’s another set. On this bedding plane are four such assemblages.

3 DSC_0178 copyHere’s another gastropod, this one with heavy spines.

4 DSC_0179 copyA high-spired gastropod is on the left, with a mytilid in side-view on the right.

5 DSC_0181 copyAnother gastropod to end the set. These are just a few of the many such fossils exposed on this bedding plane of the Matmor Formation.

Paleontological heaven in the northern part of Makhtesh Gadol

March 17th, 2016

0 Makhtesh Gadol satellite viewMITZPE RAMON, ISRAEL — Today I spent quality time with two Israeli students and some of the most interesting fossils in the world. Yael Leshno and Or Eliasson, students at Hebrew University, joined me for a walking journey through the Zohar and Matmor Formations (Middle Jurassic) in the northeastern part of Makhtesh Gadol. I’ve included a Google map above showing the makhtesh (an erosional crater in a breached anticline, to make it simple). The structure is about 10 km long, walled by Cretaceous sandstones with a soft, delightful core of Jurassic sediments. We worked today in a portion south of the main road through the makhtesh.

1 SU51 view 031716Or is standing here on the top of the basal unit of the Matmor Formation. We used this surface as a walkway to the brown hills in the background. Our first goal was to visit several outcrops of “Subunit 51”.

2 SU51 at 004This unremarkable scene is actually the location of important and very well preserved Jurassic invertebrate fossils. The brown marls are the easternmost exposure of Subunit 51 of the Matmor Formation. They are loaded with corals, echinoids, crinoids, brachiopods, bryozoans (yes!), and other treasures. The soft marl helped preserve the fossils from most of the ravages of diagenesis, and makes them easy to free from the matrix. Some of the fossils we found here will be future Fossils of the Week on this blog. I particularly enjoyed our work in this interval today because Yael and Or are such excellent field paleontologists. They put their young eyes to good use.

3 Yael ZoharAfter lunch on the Matmor Formation, we walked south to find the lowest exposures of the Zohar Formation, which underlies the Matmor and “Kidod”. Here is the first outcrop we found, located in a wadi. Yael is doing here lithological and paleontological descriptions so that she can plan her next expedition to these rocks for her dissertation work.

4 Zohar long viewThe lowest Zohar Formation in the makhtesh is exposed along a central wadi. Yael is on the skyline scouting it out. The upper beds where she is walking are very rich in mollusks, brachiopods, and echinoderms.

5 Zohar view 031716The Zohar Formation contains alternating limestones and marls, much like the Matmor.

6 Zohar ThalassinoidesThis is the underside of a thick layer of Zohar Formation limestone. It has convex hyporeliefs of Thalassinoides burrows about 5-10 cm in diameter. These were produced by burrowing crustaceans in shallow waters. The early geologists in this area did not recognize these features as trace fossils, referring to them as “negative mudcracks”.

7 Zohar and ballonIn this perspective on the Zohar limestones, you can just make out a white balloon in the far distant sky. This tethered balloon is operated by the Israel Defense Forces to watch over the border with Jordan with all kinds of fancy detection equipment (I imagine).

8 Gecko 031716This little gecko watched us work at the Zohar outcrop.

9 Mousterian workshop floorOn our walk back to the car, sharp-eyed Or pointed out numerous flint flakes in a patch of desert pavement several meters square. These are the remains of a tool-making workshop. These are Mousterian and, astonishingly, about 150,000 years old. They were worked by Neanderthals!

10 Lithic Core Negev 585This is a lithic core, from which flakes were chipped by our busy cousins. I’ve seen this flint material all over the Negev, but hadn’t realized how old it is and who was responsible. I am very much in the Old World here.


Exploring the top of the Matmor Formation (Middle Jurassic) in Makhtesh Gadol

March 16th, 2016

1 SU65 south view 031616MITZPE RAMON, ISRAEL — Today I joined four Israeli colleagues to study in detail the top of the Matmor Formation (Callovian, Middle Jurassic) in Makhtesh Gadol, Negev Highlands, southern Israel. The view above is looking south in the Matmor Hills along this upper section. You can see why this kind of exposure is popular with geologists. I love to be able to walk along a single rock unit for kilometers, noting its changes and the distribution of its fossils.

2 Field start 031616Our party consisted of the two Yaels (Edelman-Furstenberg and Leshno), Rivka Rabinovich from Hebrew University and the National Natural History Collections, and her undergraduate student Or Eliasson. We started along the Goldberg section and worked our way up the formation.

3 Quadrat group 031616We concentrated on getting Yael Leshno’s PhD dissertation data collection methods established. Here she sits (in the green scarf) with her advisors Rivka Rabinovich on the left and Yael Edelman-Furstenberg on the right. They are gathering data from a quadrat in Subunit 65 of the Matmor.

4 SU65 view 031616This particular subunit (a term and designation from Goldberg, 1963) is of particular importance to us because it is exposed in the north of the makhtesh as a spectacularly fossiliferous bedding plane. Here we see the same fossils, but they are fully embedded in the calcareous matrix. Or is the young man above searching for fossils, a task he is very good at.

5 Field end of day 031616That was basically our day! The weather was better, with less wind (although still plenty) and far less dust.

A day in the Zohar and Matmor Formations of the Negev

March 15th, 2016

1 Zohar outcrop 031516MITZPE RAMON, ISRAEL — It was another very windy day in southern Israel, but still just fine for fieldwork. Yael Edelman-Furstenburg, Yael Leshno and I returned to Makhtesh Gadol to work on Yael Leshno’s data collection procedures for her PhD project in the Middle Jurassic sequence here. Our first task was figuring out the detailed stratigraphy, which is not especially easy considering all the faulting and somewhat dated lithological descriptions for orientation. The above image is of the Zohar Formation just below its contact with the Kidod Formation (depending on what stratigraphic scheme you follow!).

2 Zohar disconformityThe top few meters of the Zohar Formation are a series of argillaceous limestones with numerous trace fossils (Planolites and Thalassinoides, mainly) and this gorgeous erosion surface (disconformity). The white limestone beneath was lithified when it was exposed and downcut by sand-bearing currents. On the left you can see pieces of the limestone incorporated into the overlying calcareous sandstone. Classic.

3 Goldberg trench 031516We then moved up section into the Kidod Formation (or upper Zohar!) to the site of the first stratigraphic column constructed through these rocks. Right of center you can see a trench dug into the marls by Moshe Goldberg in 1962. This was part of his project to describe the entire Jurassic section in Makhtesh Gadol. We still use his iconic work today as “Goldberg, 1963”.

4 Quadrat start 031516Here are the Yaels starting the very first quadrat measurements within the Matmor Formation. Within a half-meter square they are counting and identifying all the fossils — every little bit over a few millimeters. Student Yael has many of these quadrats in her future!

5 Makhtesh view 031516Here is a view of the Makhtesh with the Yaels at work. You can see our white field vehicle from the Geological Survey in the middle distance.

6 Matmor bedding plane 031516We ended the day at this bedding plane in the upper Matmor Formation I remembered finding many years ago. It has spectacular clam and gastropod fossils across its surface, many in apparent life positions. I’d show you images of the critters, but I’m saving them for a Fossil of the Week post!


Return to Makhtesh Gadol … and introducing the Yaels

March 14th, 2016

1 Yaels Makhtesh view 031416MITZPE RAMON, ISRAEL–Today I went to one of my favorite geological places: Makhtesh Gadol in the northern Negev highlands of Israel. It was a special day as well because I worked there with two excellent geologists: Yael Edelman-Furstenberg of the Geological Survey of Israel, and Yael Leshno, a graduate student at Hebrew University beginning a project comparing the Middle Jurassic communities in the south of Israel with their temporal equivalents in the north. Yael E-F is one of Student Yael’s advisors; I am on her dissertation committee. The two Yaels are shown above in the Matmor Hills of Makhtesh Gadol sorting out the complicated stratigraphy.

2 Yaels at 055 031416Yael Edelman-Furstenberg is on the left and Yael Leshno is on the right (along with my intruding shadow). We are standing at GPS location 055, where fossils from Subunit 51 of the Matmor Formation are abundant. Student Yael is presently surveying the Middle Jurassic sections in Makhtesh Gadol to find suitable places to do stratigraphic fossil collecting and quadrat measurements.

3 Oolite unit bedding planeWe spent some time studying “the oolite unit” (Subunit 63) at the top of the original Goldberg (1963) stratigraphic section. It is, as Goldberg wrote on his column, a “characteristic guide horizon”. It’s curious because there are no other oolitic units in the Matmor Formation, and because it loses its oolitic nature a few hundred meters south and north of the section. I will make a thin-section of this rock and see what’s up with these ooids.

4 Oolite unit weatheringText

5 Jeffs PerchThe top of the triangular cliff has an exposure of a fossiliferous marl of the Matmor Formation. In 2005, Jeff Bowen (’06) perched up there for hours and collected tiny specimens.

6 Jeffs viewThis would have been Jeff’s view of the makhtesh as the sun began to set. I hope he appreciated it!

7 Sponge embedment MatmorFinally, here is a bathroom counter (the best light in my hotel room) image of a calcareous sponge I found in Subunit 60 (just below Jeff’s location above) with embedment structures (bioclaustrations). Some worm-like organisms lived within the sponge body, and the sponge grew skeleton around them. I’ve not seen these before in sponges.

Wooster’s Fossils of the Week: Zig-zag oysters from the Middle Jurassic of southern Israel

December 4th, 2015

Actinostreon Matmor Jurassic 171 173 585These pretty little oysters are from the Matmor Formation (Middle Jurassic, Callovian) of Makhtesh Gadol in southern Israel. Because I regrettably missed going to Israel for fieldwork this summer, I thought I’d choose these exquisite fossils to be celebrated this week. The genus is Actinostreon Bayle, 1878. There may be more than one species here, so we’ll just leave the identification at the genus level.
Actinostreon single 585Actinostreon is very common in some units of the Matmor Formation. Hundreds can be found scattered through a single unit. They were epifaunal filter-feeders as all oysters, and like most attached to hard substrates. The Actinostreon in the Matmor Formation commonly settled on small shell fragments in marl, giving them the appearance of dwelling in mud. Their zig-zag commissures (their shells are formally called plicate) strengthened their shells with ribs and helped them maintain high water inflow for filter-feeding with a relatively small opening (gape).
bayle 300The French paleontologist and mineralogist Claude Émile Bayle (1819-1895) named the genus Actinostreon in 1878. Bayle was raised in the beautiful French coastal city of La Rochelle. His family was related to Alcide Dessalines d’Orbigny (1802-1857), one of the greatest French naturalists, so collecting and analyzing fossils and modern shells was encouraged. Bayle studied at the Ecole Polytechnique and then the Ecole des Mines. After his schooling he was employed as the Chief Engineer of the Corps des Mines. He assembled a large collection of fossils (about 185,000 of which were cataloged). In 1848 he began teaching paleontology and mineralogy at the Ecole des Mines, retiring in 1881. His paleontological specialties were mollusks (especially Jurassic and Cretaceous bivalves) and Cenozoic mammals. He had a fairly modest publication record until he produced his magnum opus, an 1878 fossil atlas to accompany a new geological map of France. It is here that he described Actinostreon, and many other new taxa.


Alberti, M., Fürsich, F.T. and Pandey, D.K. 2013. Seasonality in low latitudes during the Oxfordian (Late Jurassic) reconstructed via high-resolution stable isotope analysis of the oyster Actinostreon marshi (J. Sowerby, 1814) from the Kachchh Basin, western India. International Journal of Earth Sciences 102: 1321-1336.

Bayle, E. 1878. Fossiles principaux des terrains: Explication carte geologique France. France Service Carte Geologique, vol. 4, pt. 1, pl. 132.

Hirsch, F. 1980. Jurassic bivalves and gastropods from northern Sinai and southern Israel. Israel Journal of Earth Sciences 28: 128-163.

Machalski, M. 1998. Oyster life positions and shell beds from the Upper Jurassic of Poland. Acta Palaeontologica Polonica 43: 609-634.

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