Wooster’s Fossil of the Week: A mystery fossil for my Invertebrate Paleontology students

September 4th, 2015

1 Stereolasma singleAt the beginning of my Invertebrate Paleontology course I give each student a fossil to identify by whatever means necessary. I challenge them to take it down to the species level, and tell me its age and likely place of collection. The fossil this year is shown above: the rugose coral Stereolasma rectum (Hall, 1843) from the Middle Devonian of New York. I collected the specimens on my western New York adventure last month from the Wanakah Shale Member of the Ludlowville Formation at Buffalo Creek in Erie County. (There were a lot of them! This coral is so common that you can buy them online at science supply stores.)

The corals I collected were well weathered on the Devonian seafloor. You can see some evidence of this in the exterior which shows opened tunnels of borings. They were not appreciably weathered on the outcrop because they were directly excavated from the shale matrix.
2 Stereolasma cross section 585This is a cross-section through one of the S. rectum specimens. The internal radiating calcitic partitions (septa) are well preserved by clear calcite cement. There appear to be at least two generations of sediment that penetrated into the interior after the death of the polyp. The posthumous events affecting these corals may be more interesting than their life histories.

That awkward species name comes from the Latin rectus for “straight”. The anatomical rectum that we all know well comes from the same root but is based on a misconception by early anatomists that the terminal part of the large intestine in mammals is straight. It’s not, as a Google search will quickly show you. (I decided against including an image.)
3 Wanakah coralsReferences:

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

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

Busch, D.A. 1941. An ontogenetic study of some rugose corals from the Hamilton of western New York. Journal of Paleontology 15: 392-411.

Stumm, E.C. and Watkins, J.L. 1961. The metriophylloid coral genera Stereolasma, Amplexiphyllum, and Stewartophyllum from the Devonian Hamilton group of New York. Journal of Paleontology 35: 445-447.

Wooster’s Fossil of the Week: An encrusted and bored oyster from the Upper Jurassic of northern England

August 28th, 2015

1 Passage Beds Oyster shell bored 585This week’s fossil is a celebration of classes beginning again at Wooster, and a memory of excellent summer fieldwork. It isn’t especially attractive, but it has paleontological significance. We are looking at a broken surface through a thick oyster from the Passage Beds Member of the Coralline Oolite Formation (Upper Jurassic, Oxfordian) exposed on the north side of Filey Brigg, North Yorkshire, England. It was collected by Meredith Mann (’16) as part of her Senior Independent Study research in June. One of her project goals is to assess the sclerobionts (encrusters and borers) that lived on and within hard substrates in this interval. This thick shell is a start.
2 Passage Beds borings 585In this closer view we can see three rounded objects penetrating the oyster shell. These are bivalve borings called Gastrochaenolites. They were open holes excavated by drilling bivalves that were later filled with sediment and cement.
3 Passage oyster encrusters 585The outer surface of the oyster shell is covered with encrusting oysters and serpulid worm tubes. These will be more visible later after Meredith prepares the specimens. The first thing she is likely to do is use some bleach to remove the modern marine algae. Our specimens were all collected near the high-water tide level on the rocky north coast of Filey Brigg (N54.21823°, W00.26904°).
4 Meredith Passage Beds  072415Meredith is here standing against the Passage Beds Member on June 14, 2015. Her feet are on the top of the underlying Saintoft Member of the Lower Calcareous Grit Formation. About a meter and a half above her head is the base of the overlying Hambleton Oolite Member (Lower Leaf) of the Coralline Oolite Formation. As we took this photo the sea was pounding behind us on a rising tide.
5 Passage Unit 1 fossils 072415Here is a cluster of oysters preserved in the lowest unit of the Passage Beds. It is a sandstone distinct from the overlying limestones. There is much evidence of high-energy transportation of shelly material.
6 Meredith collection 072315Here are Meredith’s specimens from this site, all cleaned and in stratigraphic order. A critical part of her work will be a petrographic analysis of the Passage Beds Member. We hope to show you these thin-sections next month.
7 Meredith Filey Brigg point 072415Meredith celebrating the end of her fieldwork as she confronts the rising sea on the tip of Filey Brigg (N54.21560°, W00.25842°).

Wooster’s Fossil of the Week: A blastoid from the Lower Carboniferous of Illinois

August 21st, 2015

Pentremites IL 585It is sometimes hard to believe that exquisite fossils such as the above are sometimes very common. The above is a theca of the blastoid Pentremites godoni (DeFrance, 1819) found in the Lower Carboniferous (Mississippian) of Illinois. (Thanks to expert Colin Sumrall for the identification.) In some places these fossils can be picked up by the hundreds.

Blastoids are stemmed echinoderms that appeared first in the Ordovician and went extinct at the end of the Permian. They were most diverse and abundant in the shallow carbonate seas of the Lower Carboniferous, especially in North America. They are much beloved and studied fossils.
Pentremites IL basal 585The basal side of the above theca shows that blastoids had a small circular stem attachment, much like their cousins the crinoids. They extended numerous feeding appendages (brachioles) from their ambulacra (the five “petals” on the upper surface and sides) for filter-feeding. The theca is made of calcitic plates that are tightly fused together, thus ensuring they survive the vicissitudes of preservation.
Pentremites close 585In this close view of the top of the theca are five holes (spiracles) surrounding a central pit (the mouth) One spiracle (in the upper right) is larger than the others. It contains the anus and is thus called an anispiracle. The spiracles are openings into the interior of the theca, which contained a complexly-folded respiratory system called the hydrospire.

Pentremites godoni has a complicated taxonomic history. The original type specimen of the species (a specimen used as the definition of the species — a Platonic ideal form!) was destroyed in the middle of the 19th Century in a museum fire. The specimen was illustrated and described (although not named) in 1808 by James Parkinson (see below).
Screen Shot 2015-07-21 at 4.55.39 PMScreen Shot 2015-07-21 at 4.59.30 PMParkinson (1808, pl. 13) referred to this specimen as “an asterial fossil from America; probably of the nature of the encrinus.” Encrinus was a term used at the time for crinoids. Fay (1961) describes the convoluted way Parkinson’s specimen above became the type not only for the species, but also how P. godoni came to define the genus Pentremites as well. That Parkinson (1808) diagram, though, is the only image of the original specimen, and probably the first illustration of a blastoid.

References:

Atwood, J.W. and Sumrall, C.D. 2012. Morphometric investigation of the Pentremites fauna from the Glen Dean Formation, Kentucky. Journal of Paleontology 86: 813-828.

DeFrance, J.M.L. 1819. Dictionnaire des Sciences Naturelles 14, EA-EQE, p. 467.

Fay, R.O. 1961. The type of Pentremites Say. Journal of Paleontology 35: 868-873.

Parkinson, J. 1808. Organic remains of a former world. London, Noraville & Fell, v. 2, p. 235-236, pl. 13.

Waters, J.A., Horowitz, A.S. and Macurda, D.B., Jr. 1985. Ontogeny and phylogeny of the Carboniferous blastoid Pentremites. Journal of Paleontology 59: 701-712.

Wooster’s Fossil of the Week: A very large Upper Jurassic ammonite from southern England

August 14th, 2015

1 Titanites fragment Bowers QuarryThe shard above doesn’t look like much. It comes from a specimen far too large for us to excavate, let alone pack onto a plane for the trip home.
2 TitanitesinrockHere’s a view of one of the full specimens still in bedrock.
3 KN&Titanites 2002And here we see a liberated specimen with Katherine Nicholson Marenco (’03) for scale 12 years ago. This is the ammonite Titanites anguiformis Wimbledon and Cope, 1978, from the Portland Freestone (anguiformis Zone, Portlandian, Upper Jurassic) exposed on the Isle of Portland in Dorset, southern England. Katherine and I, with help from Rich Poole (’03), Clive Griffiths, Tim Palmer and Paul Taylor, worked there in the summer of 2002 looking at encrusting faunas on shells for her Independent Study project. We could only take bits home, hence the fragment above. It was a wonderful field season in a spectacular place.

Titanites anguiformis is one of the largest ammonites, with specimens up to a meter in diameter. Our specimens above are all molds made of limestone; the aragonitic shells dissolved away. These lumbering beasts were swimming predators like all ammonoids, feasting on a variety of invertebrates in a shallow Jurassic sea.
4 CoombefieldBlocks2Our team spent most of its time in active building stone quarries like this one (Coombefield) looking at excavated blocks of Portland Freestone. This rock is one of the most comon building stones in England.
5 KNChiselling2The many surfaces of the blocks exposed fossils in a variety of orientations. Here is Katherine doing what she did for three weeks: chiseling bits of shell from the limestone.
6 Titanitesclose-up1Our goal was to collect surfaces like this. We have here an internal mold of Titanites anguiformis. The inner surface of the shell (a cryptic space) was encrusted by bryozoans, serpulid worms and oysters. When the aragonitic shell dissolved, the undersides of the encrusters were exposed like we see here. We then studied the attachment surfaces of the encrusters, looking at their growth patterns and successional overgrowths. Katherine’s work resulted in this GSA presentation.

[#Beginning of Shooting Data Section] Nikon CoolPix2500 2002/06/18 10:24:09 JPEG (8-bit) Normal Image Size:  1600 x 1200 Color ConverterLens: None Focal Length: 5.6mm Exposure Mode: Programmed Auto Metering Mode: Multi-Pattern 1/900.9 sec - f/4.5 Exposure Comp.: 0 EV Sensitivity: Auto White Balance: Auto AF Mode: AF-S Tone Comp: Auto Flash Sync Mode: Not Attached Electric Zoom Ratio: 1.00 Saturation comp: 0 Sharpening: Auto Noise Reduction: OFF [#End of Shooting Data Section]This fossil bit is thus a reminder of a great field season on the coast of southern England many years ago.

References:

Falcon‐Lang, H. 2011. The Isle of Portland, Dorset, England. Geology Today 27: 34-38.

Wimbledon, W.A. and Cope, J.C.W. 1978. The ammonite faunas of the English Portland Beds and the zones of the Portlandian Stage. Journal of the Geological Society of London 135: 183-190.

Final day in the Silurian of New York

August 9th, 2015

1 Caleb new excavationLOCKPORT, NEW YORK (August 9, 2015) — This was the last day in the field for Andrej Ernst and me. We met all our goals (collecting bryozoans from the Rochester Shale, finding sclerobionts anywhere, and learning more about New York fossil localities) and had a great time. Now we have two days left to pack our specimens, ship those going to Germany, and review our notes. We will probably get some time tomorrow to see Niagara Falls!

We worked this morning in Caleb’s Quarry, a place we visited on our first day. Paul Chinnici, one of the fossil enthusiasts working this quarry, was our generous host. We were impressed with how much has changed in just the five days since our last time here. The large excavation above, for example, is new. This is fossil-collecting at a very large scale!

2 Caleb blocksAndrej searched for more bryozoans in the top layers of the shales while I studied these blocks of resistant calcareous siltstones and limestones. They are from a layer about midway down in the quarry. The shales erode to clay around them while they stand in relief.

3 Caleb block plan viewThe blocks have excellent trace fossils, including Chondrites seen in this bedding-plane view on the top of a block. Chondrites was made by small animals mining the sediments for deposited organic material.

4 Caleb block side viewThe trace fossils cut down into the siltstone, seen here in side view. The tunnels are filled with a clay-rich sediment that weathers a lighter color, giving us this contrast.

5 Caleb turbiditeMany of the blocks show a turbidite-like structure, with coarse shelly debris at the base and cross-bedded siltstone above. This may mean that the deep-waters that accumulated the clays to make the gray Rochester Shale were occasionally disturbed by massive turbidity flows of a sediment-water slurry. Were these triggered by storms or seismic events connected to orogenies to the east?

6 Caleb block stone in placeBecause of the recent excavations at Caleb’s Quarry, we were able to see this persistent calcareous siltstone in its stratigraphic context. It is here marked by the hammer. Note the gray shales above and below.

With this last observation, our fieldwork is officially done!

7 Paper pulp factory Lockport CaveDuring the afternoon we again visited the Erie Canal locks in Lockport. This time we took a tour of “Lockport Cave”, which is really a set of tunnels dug in the mid-19th century to channel river water through “races” to power factories. It is quite an ingenious use of hydropower before electricity. Above are the remains of the last of these water-powered factories, a paper pulp mill.

8 Lockport Cave entranceWe entered the main tunnel through a massive pipe that used to bring fast-flowing water to water wheels in the paper factory. The pipe is eight feet in diameter, and the water flowed at about 12 miles per hour.

9 Lockport Cave entrance pipeThis is the only one of my interior photos to succeed. The place was fascinating, even if it was cool, damp and dark. The trip included a short underground boat ride along a narrow water channel.

10 Upside-down railroad bridgeFinally, just because it is cool, here is the Lockport Railroad Bridge over the Erie Canal. It is called “the upside-down bridge” because the trusses are underneath the tracks. The legend is that the railroad company built the bridge this way to limit the height of boats on the canal, thus limiting its competition for cargo transport!

Return to the Silurian of New York

August 8th, 2015

1 Cichorium intybus SR 93 585LOCKPORT, NEW YORK (August 8, 2015) — Andrej and I began some deep collecting of Silurian localities in the Lockport area today in our survey of the bryozoan and sclerobiont faunas. The sites are, shall we say, not the most attractive, so let’s start with this common but gorgeous flower along the roadsides in western New York: Cichorium intybus (chicory). It is an invasive perennial from Europe that now has a global distribution. It has its uses as a coffee substitute, livestock feed, and salad stock. I love the color and serrated leaves.

2 Andrej Hickory CornersAnd here is why we lead with a flower. Andrej Ernst is sorting through samples from the Hickory Corners locality on State Route 93 in Lockport. The fossiliferous limestone here is the Hickory Corners Member of the Reynales Formation (Lower Silurian, Aeronian). The bryozoans are wonderfully diverse, and the top of the unit is a bored carbonate hardground. We happily collected here most of the morning, despite the trash and traffic.

3 Lewiston B beds Niagara RoadWe returned to a site along railroad tracks at Niagara Street in Lockport to collect from the Lewiston Member, part B, of the Rochester Shale. Again, the bryozoans here are fantastic, including my new favorite, a delicate cyclostome named Diploclema.

4 Lewiston E Burleigh Hill Shale LaFarge QuarryOur last site of the day was along the entrance road to a quarry. With all the surrounding rock, the only fossiliferous horizon is exposed in a shallow drainage cut in the road itself. Andrej is pulling a few bryozoans from the top of Lewiston Member, part E, of the Rochester Shale. The thick shales above him are the Burleigh Hill Formation.

5 Erie Canal at LockportWhen our work was done for the day, we became tourists and visited the Erie Canal locks in Lockport. (Hence the name!) This is a view looking east from the bottom of the two-lock sequence. We wanted to see the locks actually transport a boat, but it was a slow Saturday afternoon.

6 Erie Canal Lock LockportA view of the massive doors upstream of one of the modern locks. The engineering feats here date back to the early 1820s.

7 Crinoidal cross-sets Erie CanalGeology is evident here too. This is a block of crinoidal limestone showing cross-stratification. Many of the older buildings in Lockport are made of Silurian stone excavated to create the Erie Canal.

Wooster’s Fossil of the Week: Small and common orthid brachiopods from the Upper Ordovician of Ohio

August 7th, 2015

Cincinnetina meeki (Miller, 1875) slab 1 585
One of the many benefits of posting a “Fossil of the Week” is that I learn a lot while researching the highlighted specimens. I not only learn new things, I learn that some things I thought I knew must be, shall we say, updated. The above slab contains dozens of brachiopods (and a few crinoid ossicles and bryozoans). I have long called the common brachiopod here Onniella meeki. Now I learn from my colleagues Alycia Stigall and Steve Holland at their great Cincinnatian websites that since 2012 I should be referring to this species as Cincinnetina meeki (Miller, 1875). Jisuo Jin sorted out its taxonomy in a Palaeontology article three years ago:

Phylum: Brachiopoda
Class: Rhynchonellata
Order: Orthida
Family: Dalmanellidae
Genus: Cincinnetina
Species: Cincinnetina meeki (Miller, 1875)
Cincinnetina meeki (Miller, 1875) slab 2 585This slab, which resides in our Geology 200 teaching collection, was found at the famous Caesar Creek locality in southern Ohio. It is from the Waynesville/Bull Fork Formation and Richmondian (Late Ordovician) in age.
Cincinnetina meeki (Miller, 1875) slab 3 585You may see some bryozoans in this closer view. This bed is a typical storm deposit in the Cincinnatian Group. The shells were tossed about, most landing in current-stable conditions, and finer sediments were mostly washed away, leaving this skeletal lag.

Reference:

Jin, J. 2012. Cincinnetina, a new Late Ordovician dalmanellid brachiopod from the Cincinnati type area, USA: implications for the evolution and palaeogeography of the epicontinental fauna of Laurentia. Palaeontology 55: 205–228.

A day’s excursion into the Middle Devonian of western New York

August 7th, 2015

1 Wanakah at Buffalo CreekLOCKPORT, NEW YORK (August 7, 2015) — Today Andrej Ernst and I were able to join Brian Bade and his friends on a collecting trip up Buffalo Creek in Erie County, New York. Our goal was simply to look for interesting fossils in the Wanakah Shale Member of the Ludlowville Formation (Middle Devonian) and enjoy the fellowship of fossil enthusiasts. Success on both counts. It was a great day, and rather fun wading through the cool waters of the creek as we examined the shale on the banks.

2 Wanakah TrilobiteHere is an external mold of a trilobite in the soft Wanakah Shale. An external mold is an impression of the exterior of the organism. If you look at this upside-down it pops into reverse relief! This fossil is not recoverable because it would break into bits with any attempt to hammer it out. Andrej and I found plenty of bryozoans here, along with other cool fossils.

3 Bethany Center Centerfield LimestoneAs a bonus we also were able to visit the Bethany Center exposure of the Centerfield Limestone, also Middle Devonian. There isn’t much left of the exposure, as you can see, but we still found numerous encrusting organisms (sclerobionts) on brachiopods and the abundant rugose corals. We also got plenty of sun here.

Into the Niagara Gorge

August 6th, 2015

1 Lewiston-Queenston Bridge 080615LOCKPORT, NEW YORK (August 6, 2015) — It holds one of the strongest river currents in the world, the gorge of the Niagara River below Niagara Falls. That tremendous flow has cut a deep canyon through the Silurian rocks of the region, providing a superb opportunity for geologists to see the local stratigraphy and paleontology. Today our team walked into the gorge from Lewiston, New York, to explore the section. Carl Brett was our guide. Above is a view of the gorge at the Lewiston-Queenston Bridge that joins the USA on the right with Canada on the left. The forests are plenty dense, but there are rocks in those steep walls.

2 Gorge trailWe hiked along the Gorge Trail on the USA side upriver from Lewiston. The trail is actually an old road built for transport of construction materials used for the hydroelectric dams upriver.

3 Gorge block 080615We learned most of the geological context by examining fallen blocks along the trail. This was an interesting way to see the stratigraphy because the different formations dropped blocks randomly along the path.

4 AE080615I tried to get a surreptitious picture of my German colleague Andrej Ernst.

5 Grimsby crossbedsThe Grimsby Formation (Lower Silurian, Llandoverian) is a sandstone that has numerous sedimentary structures, including nice cross-sets.

6 Kinneyia Grimsby Niagara GorgeAndrej found this nice specimen of an enigmatic feature called Kinneyia. It may be a function of gas build-up underneath microbial mats on the ancient seafloor. I’ve always called it “elephant skin”.

7 Niagara Gorge section 080615A view of the gorge wall above us.

8 Rochester collecting Niagara GorgeWhen the trail reached the Rochester Shale, we spent some time searching it for fossils. The most common finds were cystoids (especially Caryocrinites) and the odd coronoid Stephanocrinus.

9 Andrej Carl 080615Andrej Ernst and Carl Brett on the Rochester Shale outcrop in the Niagara Gorge. Andrej noted many neglected bryozoans in the fossil fauna exposed here.

10 Sir Adam Beck Hydroelectric Generating StationsOur final stop was opposite the Sir Adam Beck Hydroelectric Generating Stations built on the Canadian side of the gorge. It is an awesome feat of engineering, and a prodigious amount of concrete.

We had an excellent time in the Niagara Gorge. I was at last able to see some of the nuances of Silurian stratigraphy that Carl Brett was explaining. As you can see, the weather was ideal.

We said goodbye to Carl at the end of the day as he departed for fieldwork in nearby southern Ontario.

 

Wooster Geologist in New York

August 5th, 2015

1 Calebs Quarry 080515LOCKPORT, NEW YORK (August 5, 2015) — What looks like an ordinary commercial quarry above is actually quite unusual. It is an excavation done entirely by amateur paleontologists (“citizen scientists”) to collect and preserve fossils from the Rochester Shale (Upper Silurian, Wenlockian). The story of Caleb’s Quarry is well told in the linked American Museum of Natural History article. It is near Lockport, New York, and one of the most famous fossil sites in the region. I’m lucky to be here.

This late summer expedition to New York is to help my German friend Andrej Ernst (University of Hamburg/University of Kiel) collect bryozoans from the Rochester Shale. This bryofauna is inadequately described for phylogenetic and biogeographic analyses, so Andrej has a grant to do the deed from outcrop sampling to preparation, analysis and publication. While assisting Andrej, I am also scouting out new localities for future geology Senior Independent Study projects at Wooster. We will be in Niagara and Erie Counties for a week doing this work.

2 CarlCalebsAbsolutely critical to the project is the field advice and direction of Carl Brett (University of Cincinnati). Carl is without peer when it comes to many paleontological and geological topics, but for the Silurian of New York he is one of the gods. Carl grew up in the region and has been studying the rocks and fossils since he was a young teenager. He gave us two days of magnificent stratigraphic instruction, and he introduced us to the amateur team digging at Caleb’s Quarry. We were also joined for three days by Brian Bade, a citizen scientist from Ohio with an extraordinary passion for fossils, along with deep knowledge and appreciation for how science works.

3 FredandCarlCalebsFred Barber, one of the excavators at Caleb’s Quarry, is here showing Carl Brett magnificent crinoids collected from this locality.

4 Crinoid Calebs 080515The gray shale matrix is homogenous and soft enough to be removed from the fossil by an expert preparator. This crinoid shows outstanding preservation down to the pinnules on its arms.

5 Bryozoan Calebs reconstructedOf course, Andrej and I are most interested in the bryozoans from Caleb’s Quarry. Here is a beautiful specimen that has been carefully reconstructed.

6 StriispiriferCalebsI found these brachiopod-rich beds intriguing. Striispirifer is a new name to me.

7 DalmanTriloCalebsTrilobites are always the stars of Paleozoic fossil sites like this. While we were at the quarry we watched one of the excavators (Kent Smith) unearth this gorgeous specimen. I believe it is Dalmanites limulurus.

8 ChondritesCalebsThe trace fossils here are very interesting. There may be project possibilities with this ichnofauna because of the diversity present at the quarry and the bedding plane exposures. This is the trace fossil Chondrites.

9 Jungle Jeddo tributaryAfter our quarry visit today we then stopped at some other exposures of the Rochester Shale. This scene shows what fieldwork is like without quarries and roadcuts! We are here along a tributary of Jeddo Creek, at the top of Lewiston Member B of the Rochester Shale. Hard to tell, eh?

10 Brian Jeddo Tributary Lewiston BHere Brian Bade is examining a deeply weathered section along the creek. Years ago Carl Brett took advantage of this disaggregation of the Rochester Shale to sieve the sediment for small fossils. He has generously given us the “washings” from this cut, which represent months of his work as a graduate student. They are loaded with tiny bryozoan bits, along with many other taxa.

11 Cherokee UnconformityWe ended the day with a look at several other outcrops in the Lockport area. The impressive contact here between the massive sandstone and the underlying red shales is called the Cherokee Unconformity. It is a megasequence boundary correlated across most of North America. It was thought until recently to be the Ordovician-Silurian boundary, but now all you see in this image is considered latest Ordovician.

 

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