Wooster’s Fossils of the Week: An encrusted and bored coral (maybe) from the Upper Ordovician of southeastern Indiana (Part I)

March 25th, 2016

1 TopEncrustedTetradiumI found this lump of a gray rock in southeastern Indiana along a highway near the town of Liberty. It is from the Saluda Formation (Upper Ordovician), a thin unit that was likely deposited in very shallow, lagoonal waters along the Cincinnati Arch. It is not especially notable in this view. I intend to show you the wonders that can be revealed in such dull rocks by simply sawing them in half. First, though, let’s have a look at the outside. Inn the view above you can see on the left side a large trepostome bryozoan with some irregular holes in it. We’ll come back to that.

2 BaseEncrustedTetradiumFlipping the rock over we find that most of it is a fibrous fossil shaped like a dinner plate with limestone matrix and encrusting bryozoans covering most of the center.

3 CloserTubesTetraA closer view of the fibrous part shows thousands of thin tubes radiating out from the center of the plate. This is the Ordovician fossil known as Tetradium. It is strange and mysterious enough that we will use the next Fossil of the Week blog post to describe it. It has been called a chaetetid sponge (as in Termier and Termier, 1980); a “calcareous filamentous florideophyte alga” (Steele-Petrovich 2009a, 2009b, 2011; she renamed it Prismostylus), and most commonly a coral of some sort (Wendt, 1989). Interesting range of options! We’ll explore later.

4 Catellocaula122915Now, back to the trepostome bryozoan visible on the top surface. There are three kinds of holes on this specimen. The smallest are the zooecia of the bryozoan itself, each of which would have hosted a zooid (a bryozoan individual). They are the background texture of the fossil. The large holes above are a bioclaustration structure that Time Palmer and I named in 1988 as Catellocaula vallata (little chain of walled  pits). It is explained thoroughly in one of the early Fossil of the Week posts. Basically they are pits formed when the bryozoan grew up and around some sort of soft-bodied colonial organism sitting on top of the surface, forming these embedment structures connected together by tunnels at their bases.

5 Trypanites122915A third kind of hole in this bryozoan is a boring cut down into its skeleton. These are the trace fossil Trypanites, formed when some kind of filter-feeding worm bored straight into the calcite zoarium (colonial skeleton) to make a protective home, as many polychaete worms do today.

Now let’s cut this stone in half —

6 Tetradium cavernInside we find a wonderful cavern of crystals — a geode! The crystals are mostly calcite, with dog-tooth spar lining the cavity and blocky spar replacing large parts of the Tetradium skeleton. There’s a story here, and it will be told in the next Fossil of the Week post!


Hatfield, C.B. 1968. Stratigraphy and paleoecology of the Saluda Formation (Cincinnatian) in Indiana, Ohio, and Kentucky. Geological Society of America Special Papers 95: 1-30.

Li, Q., Li, Y. and Kiessling, W. 2015. The first sphinctozoan-bearing reef from an Ordovician back-arc basin. Facies 61: 1-9.

Palmer, T.J. and Wilson, M.A. 1988. Parasitism of Ordovician bryozoans and the origin of pseudoborings. Palaeontology 31: 939-949.

Steele‐Petrovich, H M. 2009a. The biological reconstruction of Tetradium Dana, 1846. Lethaia 42: 297-311.

Steele‐Petrovich, H M. 2009b. Biological affinity, phenotypic variation and palaeoecology of Tetradium Dana, 1846. Lethaia 42: 383-392.

Steele-Petrovich, H.M. 2011. Replacement name for Tetradium DANA, 1846. Journal of Paleontology 85: 802–803.

Termier, G. and Termier, H. 1980. Functional morphology and systematic position of tabulatomorphs. Acta Palaeontologica Polonica 25: 419-428.

Wendt, J. 1989. Tetradiidae — first evidence of aragonitic mineralogy in tabulate corals. Paläontologische Zeitschrift 63: 177–181.

A Wooster Geologist visits the caves of Tel Maresha in central Israel

March 21st, 2016

1 Bell caves MareshaTEL AVIV, ISRAEL — My last day in Israel was spent with my friend Yoav Avni exploring some sites in the central part of the country before my flight left Tel Aviv late in the evening. The most geological place we visited was Maresha (which later became, in order, Beit Guvrin, Eleutheropolis, Bethgibelin, Bayt Jibrin, Kibbutz Beit Guvrin and Beit Guvrin National Park — you know there’s a long story there!). Maresha was an 8th Century BCE Israelite city in Judah that guarded several trade routes and access to the Judean hills from the coast. It thus had significant strategic value and was subject to just about every conqueror of the region since the Iron Age. The bedrock has a very thick section of the Maresha Formation (Eocene), a homogeneous soft chalk that is easily carved. This chalk has long been quarried for building stone and the main component of plaster and cement. The typical quarries are bell-shaped, with a small circular entrance from ground level and an expanding cone downwards. Above we see several intersecting quarries exposed by a roof collapse.

2 Bell caves signHere is a helpful diagram showing the construction of bell caves. The top geological layer is a hard calcrete (caliche) locally called nari. It provides a strong roof for the quarries.

3 Bell cave openingThe opening of a bell cave through the calcrete upper layer.

4 Bell cave carving marksThe sides of the quarries easily show the tool marks made by the workers as they spiraled down into the bedrock. This rock is soft enough to dig with your fingernails.

5 Columbarium Maresha

Residents of Maresha, especially in the diverse Hellenistic times (2nd-3rd centuries BCE), reused the quarries for living and working spaces, expanding several into new rooms. Above Yoav is standing in the largest columbarium, a place to raise doves for food and rituals. (Not for the storage of ancestral ashes or bones, as was once thought.)

6 Yoav in Columbarium MareshaI didn’t want to crop out Yoav’s happy face! He is standing in the bottom of a bell cave repurposed as a columbarium.

7 Olive cracker MareshaThere are several underground olive oil factories that were active from the 3rd Century BCE until modern times. This device was driven by a donkey to crush raw olives.

8 Large olive press MareshaThis is an underground olive press. Heavy stones were attached to the beams to press the juices out of olives cracked first by the donkey apparatus above.

9 Siddonian cavesThe Sidonian tombs (about 2nd Century BCE) are very impressive. All the carving is original, but the paint shown above is a modern reconstruction. This inscription on a tomb here is haunting:

Nothing else remains that I can do for you, or that will pleasure you. I am sleeping with someone else, but it is you I love, dearest to me of all.

In the name of Aphrodite, I am happy about one thing, that your cloak has been left to me as a pledge.

But I flee, and permit you expanses of freedom. Do anything you desire.

Do not strike the wall; it only makes noise. We will motion to each other; this will be the sign between us.

10 Maresha countrysideThe scenery above ground at Tel Maresha is lush and green. This region received more than the usual amount of rain this season, and it shows. We are looking here from the tel towards Hebron in the Judean hills. Note the herd of sheep in the middle ground distance.

11 Bedouin sheep MareshaLater in the day we met those sheep and their Bedouin shepherds.

12 Tel MareshaAnd here is Tel Maresha itself. Only 10% has been excavated, so much more remains to be discovered.


My tradition at the end of a field excursion is to include my most important GPS numbers and coordinates:

125: N29.99183°, E35.07680° Gerofit Junction Ora Formation
126: N30.94310°, E34.97972° SU62 below oolite; nice corals
127: N30.94323°, E34.99110° Top Zohar Cliff
128: N30.95774°, E35.00615° SU65 bedding plane
129: N30.94358°, E34.97828° SU65 in Matmor Hills
130: N30.94812°, E35.00099° Lowest exposed Zohar
131: N30.33491°, E34.92828° Road to Be’er Ada
132: N30.32229°, E34.90701° Be’er Ada
133: N30.32553°, E34.90683° Near Be’er Ada along fault
135: N30.32973°, E34.91417° Ada Canyon top view
136: N30.32001°, E34.97467° Wadi Paran cliffs

Wildflowers of the Negev, 2016 version

March 21st, 2016

1 purple flower 031616MITZPE RAMON, ISRAEL — One of my last posts from a trip into the Negev is a selection of flower images. (Here is the previous wildflower post. None of the blooms are the same.) I don’t know any of their names, so I depend on commentators to help me add them. Above is a nice purple flower from Makhtesh Ramon.

2 Light purple flowersAnother purple flower, this one with four petals. Makhtesh Ramon.

3 Flower with two insectsThis swirly purple flower has two insects on it. Did one arrive to eat the other? Makhtesh Gadol.

4 Blood red flowersThese blood-red flowers are on a common shrub in the wadis.

5 Red flowersThese flowers of unusual shape are very common in all the wadis I visited.

6 Spiky bubbles bushA spiky bubble bush in Makhtesh Gadol.

7 Spiky bubbles closeA closer view of the spiky bubble bush. I was told that squeezing the bubbles produces a foul smell. I did not experiment.

8 Wrapped thistleThese thistle-like plants are always wrapped in some sort of insect or spider silk.

It was a beautiful season for flower diversity, if not abundance. Comments welcome!

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!

My neighborhood in Mitzpe Ramon, southern Israel

March 20th, 2016

1 My street MR 032016MITZPE RAMON, ISRAEL — Some images from the little town in the Negev where I spend my nights. I like being based here because my students and I are central to all of our diverse geological localities. It is also my friend Yoav Avni’s home. Plus, it reminds me of my hometown of Barstow, California, in its desert setting, diverse population, and edge-of-civilization feeling. (The architecture, though, is not at all the same!)

Hotel MR 031916I stay in the Ramon Suites hotel, which is very comfortable and reasonably priced. It is a short walk from here to the edge of Makhtesh Ramon.

2 Brooklyn house MR 032016Near the hotel is a building from Brooklyn! This is a Chabad-Lubavitch house. I’ll let this link to 770 Eastern Parkway begin the explanation. There are replicas of this house all over the world, each with the number 770.

3 Edge of town MR 032016The southwestern edge of town, with a new school and synagogue. The edge of the makhtesh is a few meters beyond the conical hill.

4 Skyline with New Hotel MROn the top of the skyline is a very fancy hotel well beyond my means. It looks cool, and strangely ancient.

5 Skyline with Makhtesh MR 032016A view to the southeast showing a wall of the makhtesh in the far background.

6 Water tower MR 032016The iconic Mitzpe Ramon water tower, visible for many kilometers. It is the most interesting thing I can see from my hotel room.

7 Childrens mural MR 032016A children’s mural on the outside of a school. Note the water tower on the left, the desert wildlife, and even a dinosaur. (No dinosaurs have been found here, alas.) This children’s view of their dry town is strangely watery.

8 Grocery store MR 032016Last and least, the town’s grocery store. Crowded and unfriendly. Always feels a bit Soviet to me, probably because as in that regime there was little choice where to shop. Still, they have kept me and my students supplied.

A geological obstacle course in Ada Canyon, southern Israel

March 19th, 2016

1 Ada canyon startMITZPE RAMON, ISRAEL — As part of our Shabbat trip today, Yoav Avni wanted to take me up Ada Canyon (N30.32973°, E34.91417°) to explore the Hazeva (Miocene) and Arava (Pleistocene). He cryptically said, “There will be places we can barely get through”. True, that. Above is Yoav at the start of the hike. Turns out this is a slot canyon with challenges.

2 Arava narrows begin“The narrow part begins”, he says helpfully.

3 Narrowing AravaAt this point I have to take off my pack to reduce my sideways width.

4 Narrow AravaAnd sideways with a twist is the only way through as the walls close in. Pro tip: Never do this when it is raining.

5 Problematic Arava sectionNow it gets problematic with boulder scrambling and claustrophobia.

6 First ladder aravaA ladder! I never did mention my aching shoulder.

7 Second ladder AravaSteps cut in the rock and then a second ladder. Going down is always easier than going up, right?

8 Rope climb AravaA knotted rope to climb the cliff! Note the shadow of successful me at the top of the last obstacle. Wondering, though, what these climbs are like on the way back.

9 Ada view 031916The view at the top of the mountain, though, really was spectacular. This is a view towards Be’er Ada, with the fault described in the previous post running diagonally across the background.

10 Hazeva cobbles 585And yes, the geology along the way! It was very impressive. The Hazeva Formation is mostly sandstone with some layers of sandy conglomerate as in the above image. It was deposited in a wetlands with occasional floods (which produced the coarse layers). The cobbles are rounded cherts derived from Jordan to the east.

11 Arava faciesThe Arava Formation was deposited in a desert much like what we see today. It is interbedded gravels (from wadis) and unconsolidated silts (from playas and saline lakes). Classic sed/strat material. It was all well worth the adventure for this aging geologist!


A Shabbat trip to Be’er Ada in the southern Negev

March 19th, 2016

1 Road to Beer AdaMITZPE RAMON, ISRAEL — Yoav Avni and I have a tradition on Shabbat. We drive somewhere to explore interesting geology and history unconnected to current projects. It’s not really work — it’s geotourism. We are, though, always talking about new ideas. Today we traveled south of Mitzpe Ramon into the “deep desert” of the Arava below the Negev Highlands.

2 MR view to JordanThe morning view south across Makhtesh Ramon was spectacular. It isn’t conveyed very well through an image only 585 pixels wide, but it is a perspective of unusual clarity. The purple streak at the top represents mountains in western Jordan. The haze just below them is in the Arava Valley. We are looking across most of the Negev.

3 Acacia grove Beer AdaOur mission today was to visit Be’er Ada (Bir Abu ‘Auda), an historic well, and the geology around it. (N30.32229°, E34.90701°, if you’re following at home.) The top image on this post is a view from the road to the well. Just above is a grove of acacia trees near the well. The abundance of these trees, and their good health, is an indication of accessible water.

4 Yoav at Beer AdaHere is Yoav peering down into Be’er Ada. (“Be’er” means well.) It is at least twenty meters deep. The base is filled with silt, so it will have to be dug out to supply water again. This well is thousands of years old and has been a critical watering spot in the Negev for traveling groups. The next nearest well is to the east about 40 km away. Another 40 km or so to the west is another well. Be’er Ada was active as late as the 1950s, and likely had sporadic use afterwards. The water here accumulates on the impermeable clays of the Taqiya Formation (Paleocene).

5 Acacia outcrop view 031916This is a view from near Be’er Ada to the main geological interest for me: the the orangish Hazeva Formation (Miocene) topped unconformably by the gray Pleistocene Arava Formation. We will spend much more intimate time with these units in the next post. Note the graceful acacia trees.

6 Beer Ada faultThis area is next to a complex fault system. On the left is a down-dropped block of Hazeva and Arava, with Cretaceous rocks on the right. The fault is also part of the reason for the subterranean water resources at Be’er Ada.

7 Ada profileIn the middle of the image is an example of the pareidolia so common in stark landscapes. Some people see a face in profile. Apparently tour guides like to call this the head of “Ada” for whom the well was named. However, there never was such a woman!

Note the excellent weather in these images. A perfect Negev day! Thank you to Yoav for being such a generous host.

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.


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