Hunting the Roadcuts of Indiana's Ordovician

[erose]

erose, that link looks useful! Although I notice it doesn't go into any descriptive details for identifying specimens. Still, a list of all known fossils and their current taxonomy is good to have. I'll be bookmarking that one...

While the hinge and pedicle opening weren't visble in the photograph.

I notice that the site erose linked has a lot of species listed that aren't shown in any other resource I have. There are several species of Cornulites, for example, and about twice as many Vinlandostrophia species as the other site lists! Positive ID would require a lot of research, although a quick check on Google searching for "Vinlandostrophia corryvillensis" turns up a Smithsonian publication that has the original description, among a lot of others! Available as a free ebook: LINK.

Have fun! I'll eventually catalog all of mine properly, but not right now. For now, the genus is enough.

I grew up in that region and it is still my absolute favorite place to hunt. At one point about 12 years ago I started a comprehensive list of all the various species that had ever been described from the Cincinnatian Series that I could find. The base list was well over 1,250 species. Bryozoans alone accounted for a large fraction. Now many of those proved to be synonymous and after sorting the best I could thru much newer publications it still came down somewhere between 700-800 species. AND new stuff is still being found and described from those rocks. Yes, your head could explode.

The Cincinnatian Series (Upper Ordovician) is one of the richest faunas in the world.

The trick with Cinci fossils is to get the stratigraphy figured out for your fossils. Some of these species have well-known ranges. There is a definite difference between what is found in the Eden, Maysville and Richmond "groups" with overlaps and sometimes gaps in the range. Even the better ID references only hit on the most well known, common or more interesting species. I have been collecting literature on the Cinci for more than twenty years and still have a long ways to go.

ID to genus is good and not too hard for some of the stuff and for certain things a species can be easily identified based on formation if known. A great example is the great big horn coral Grewingkia canadensis. It is only really found in the upper sections and there appears to be only one species. The always small horn coral Streptelasma is the only exception and, again they are always small, sometimes in pairs or triples and tend to have a flared attachment scar. There are a few other small rugose corals in the literature but they are either rare or limited in range.

And those Vinlandostrophia* (formerly Platystrophia) can usually be sorted out by formation and shape. So despite the long list of species you will most often encounter only one or two species at a time.

* Never get too hung up on knowing the most current genera for your identifications. Platystrophia ponderosa is still Vinlandostrophia ponderosa. Believe me no one goes back thru every collection and updates catalogs with every new study. A species is a species.

Oh, dang, my head just exploded!

Edited June 23, 2016 by erose

[digit]

Oh, dang, my head just exploded!

Ewww, I hate when that happens--always so messy.

The Upper Ordovician Cincinnatian Series looks to be a really interesting fauna to collect--especially if you like brachiopods. I'm glad I got the opportunity (though only a single long day) to collect some material from there. I hope to get back and maybe pick up more of the less common items like trilobites (who doesn't like trilobites?) and one day I'll spend the time to figure out what would be the best location to go hunt some blastoids. I've been in love with these little pentagonal jewels ever since I learned of their existence from photos on TFF. A nice big bowl of them would look great on the table right next to the couch. Better not get them too close to the box of chocolates or it could be bad for the teeth. Yes, I have a box of chocolates--not the Forrest Gump variety but some nice dark chocolates in a rosewood box with a custom inlay of a seahorse.

Cheers.

-Ken

[Mediospirifer]

I grew up in that region and it is still my absolute favorite place to hunt. At one point about 12 years ago I started a comprehensive list of all the various species that had ever been described from the Cincinnatian Series that I could find. The base list was well over 1,250 species. Bryozoans alone accounted for a large fraction. Now many of those proved to be synonymous and after sorting the best I could thru much newer publications it still came down somewhere between 700-800 species. AND new stuff is still being found and described from those rocks. Yes, your head could explode.

The Cincinnatian Series (Upper Ordovician) is one of the richest faunas in the world.

The trick with Cinci fossils is to get the stratigraphy figured out for your fossils. Some of these species have well-known ranges. There is a definite difference between what is found in the Eden, Maysville and Richmond "groups" with overlaps and sometimes gaps in the range. Even the better ID references only hit on the most well known, common or more interesting species. I have been collecting literature on the Cinci for more than twenty years and still have a long ways to go.

ID to genus is good and not too hard for some of the stuff and for certain things a species can be easily identified based on formation if known. A great example is the great big horn coral Grewingkia canadensis. It is only really found in the upper sections and there appears to be only one species. The always small horn coral Streptelasma is the only exception and, again they are always small, sometimes in pairs or triples and tend to have a flared attachment scar. There are a few other small rugose corals in the literature but they are either rare or limited in range.

And those Vinlandostrophia* (formerly Platystrophia) can usually be sorted out by formation and shape. So despite the long list of species you will most often encounter only one or two species at a time.

* Never get too hung up on knowing the most current genera for your identifications. Platystrophia ponderosa is still Vinlandostrophia ponderosa. Believe me no one goes back thru every collection and updates catalogs with every new study. A species is a species.

Oh, dang, my head just exploded!

So, given that the Bon Well Hill outcrop exposes three layers (Waynesville, Liberty, and Arnheim), which Vinlandostrophia species are we likely to find? The website I linked lists 9 species, of which 6 occur in one or more of the exposed layers. V. cypha occurs in all three. The site you linked lists twelve that occur in one or more of these strata! When we're collecting surface float, a find at the bottom of the exposure could be from any of them.

It's certainly an area for near-endless collecting. I can well believe it's one of the richest fossil areas in the world! (So says a collector from the Finger Lakes area of New York.... ) If it was closer to Columbus (where my in-laws live), we'd visit to hunt more often than once a trip.

Ewww, I hate when that happens--always so messy.

The Upper Ordovician Cincinnatian Series looks to be a really interesting fauna to collect--especially if you like brachiopods. I'm glad I got the opportunity (though only a single long day) to collect some material from there. I hope to get back and maybe pick up more of the less common items like trilobites (who doesn't like trilobites?) and one day I'll spend the time to figure out what would be the best location to go hunt some blastoids. I've been in love with these little pentagonal jewels ever since I learned of their existence from photos on TFF. A nice big bowl of them would look great on the table right next to the couch. Better not get them too close to the box of chocolates or it could be bad for the teeth. Yes, I have a box of chocolates--not the Forrest Gump variety but some nice dark chocolates in a rosewood box with a custom inlay of a seahorse.

Cheers.

-Ken

It's a great area for collecting lots of things. My husband and i have found a variety of bryozoans, both species of horn corals, a few bivalves, several gastropods, and recognizable pieces of a few species of trilobites in addition to the brachiopods and microfossils. No blastoids yet, but that may happen in the future. The Causeway outcrop is a good site for trilo-bits; we've found a good Acidaspis cincinnatiensis cephalon there once. On that trip, we were just collecting bags of hash plates with visible trilo-bits, and didn't realize we had something unusual until we got it home, cleaned it off, and put it under a microscope! The cephalon was about 1 cm across. Here's a link to my ID post about it: LINK. I still haven't attempted to clean it.

And I agree: blastoids in your chocolate would be hard on your teeth! Mmmm, chocolate...

[doushantuo]

The Cincinnati arch was part of the Great American Carbonate Bank.I think.

Some of you might like a little paleogeographic background:

http://mgg.rsmas.miami.edu/rnggsa/popefinal.pdf

Edited June 24, 2016 by doushantuo

[FossilDAWG]

Just for the sake of clarity, the Cincinnatian formations produce many types of fossils, but blastoids are not among them. You might get lucky and find an edrioasteroid or two (which I personally like even more than blastoids), a crinoid calyx, or (much rarer) a cystoid, carpoid, or asteroid. Edrioblastoids occur elsewhere in Ordovician rocks, and a single species of true blastoid has been found in the Benbolt Formation in eastern Tennessee, but neither are known from the Upper Ordovician of the Indiana/Ohio/Kentucky area.

Of course, blastoids are abundant at some Mississippian outcrops in the area.

Don

[digit]

The Cincinnati arch was part of the Great American Carbonate Bank.I think.

Some of you might like a little paleogeographic background:

http://mgg.rsmas.miami.edu/rnggsa/popefinal.pdf

There is a heavy amount of geology in that paper which is way above my pay grade to comprehend completely (or even partially). The images and maps at the end are a bit more accessible to give a gist of the paper's contents. Figure 2 in particular is very interesting showing the extent of the Late Ordovician outcrops in the corner where Indiana, Ohio and Kentucky meet. The Nashville Dome in Tennessee looks like it might be fertile hunting ground as well. I particularly enjoyed the name of this paper and I think "Stationary Peripheral Bulge" is a great band name.

Just for the sake of clarity, the Cincinnatian formations produce many types of fossils, but blastoids are not among them. You might get lucky and find an edrioasteroid or two (which I personally like even more than blastoids), a crinoid calyx, or (much rarer) a cystoid, carpoid, or asteroid. Edrioblastoids occur elsewhere in Ordovician rocks, and a single species of true blastoid has been found in the Benbolt Formation in eastern Tennessee, but neither are known from the Upper Ordovician of the Indiana/Ohio/Kentucky area.

Of course, blastoids are abundant at some Mississippian outcrops in the area.

Don

Agreed, edrioasteroids are pretty cool and will likely one day end up near the top of my fossil wish list and become the subject of a targeted fossil hunt. I hadn't seen blastoids in any of the imagery from the Ordovician material collected from Indiana and so didn't have my sights set on looking for those--focusing more on brachiopods and rare trilobite. I think I'll have to do some searches on TFF and see where others have been finding blastoids. It does seem that blastoids came into their own with the greatest diversity in the Mississippian so I'll have to be on the lookout for outcrops of that age.

Cheers.

-Ken

[erose]

Great Mississippian road cut on I-64 just north of Sulphur, Indiana where you can find blastoids and many other goodies.

[digit]

A quick look at the area on Google Maps shows the intersection (on ramp) of Main St and I-64 just north of Sulphur. From the street view there does appear to be some rock exposed along the northwest corner of this interchange. Looks like you might be able to pull off the side of the road before entering the on ramp and park. If this is the spot you are referring to I'll have to add it to my list of potential blastoid hunting spots. I've also read about a spot on a small creek between Floraville and Millstadt in southwestern IL pretty much spittin' distance from St. Louis. I bet I could work out a trip to hit both of those locations (and maybe any other nearby spots) based from St. Louis--a short plane ride (or long roadtrip) from South Florida.

Cheers.

-Ken

[Rob Russell]

Nice finds, Ken! Looks like the two of you had a great trip to St Leon. I'm glad to see it was worth your efforts. I wasn't sure how well the Byron road cut would produce. Three or four years back I found some huge cephalopods there. One around thirty inches long, and about ten inches in diameter. And a few others around six inches in diameter, and a foot long. Among many others. A few coiled cephalos also.

Anyway, I'm glad the tips worked out. Glad to see you guys made it productive. I wish I could have spent at least a day with you guys, but my company is swamped with houses to build. I've got work lined up through next winter! The only complaint I have is not being able to hunt fossils!!

[digit]

We had a blast at St. Leon and had the pleasure of fortuitously meeting up with Mediospirifer and her husband. If you found cephalopods at the Byron roadcut before then that probably explains the cephalopod like imprints we spotted while there--photos at the bottom of this post earlier in this topic:

http://www.thefossilforum.com/index.php?/topic/65939-hunting-the-roadcuts-of-indianas-ordovician/?p=690418

Sounds like your work is keeping you busy. While that is generally better than the alternative, It is always good to have ample "recharge" time to get out and do something fun (which for our ilk tends to be bringing home rocks).

Had a great time hunting (and then learning about) the Ordovician which was a novelty for us. I'm kinda thinking on my next trip north of focusing on the Mississippian and gathering a nice little collection of blastoids (among other things).

Cheers.

-Ken

[erose]

If asked what publications would make it possible to identify my Cincinnatian fossils as well as understand the stratigraphy, these would be the essential four:

Cincinnati Fossils—An Elementary Guide to the Ordovician Rocks and Fossils of the Cincinnati, Ohio, Region, edited by R. A. Davis. Cincinnati Museum of Natural History. ISBN 1-882151-00-3. Paperback, 61 p., illustrations, 8 pls., 1992.

Fossils of Ohio, edited by Rodney M. Feldmann and Merrianne Hackathorn. 577p., 232 figs., 12 tables, glossary, index, 1996 (rev. 2005).

A Sea Without Fish—Life in the Ordovician Sea of the Cincinnati Region, by David L. Meyer and Richard A. Davis, with a chapter by Steven M. Holland. Indiana University Press. ISBN 978-0-253-35198-2. Hardcover, 346 p., photos, illustrations, 2009.

Sampling the layer cake that isn't: The stratigraphy and paleontology of the type-Cincinnatian, edited by Richard Arnold Davis and Roger J. Cuffey. 194 p., 107 figs., tables, 2 appendixes, 1998.

All, and many other useful things, are available thru the Ohio Geological Survey: http://geosurvey.ohiodnr.gov/publications-maps-data/publications-home

[erose]

So, given that the Bon Well Hill outcrop exposes three layers (Waynesville, Liberty, and Arnheim), which Vinlandostrophia species are we likely to find? The website I linked lists 9 species, of which 6 occur in one or more of the exposed layers. V. cypha occurs in all three. The site you linked lists twelve that occur in one or more of these strata! When we're collecting surface float, a find at the bottom of the exposure could be from any of them.

It's certainly an area for near-endless collecting. I can well believe it's one of the richest fossil areas in the world! (So says a collector from the Finger Lakes area of New York.... ) If it was closer to Columbus (where my in-laws live), we'd visit to hunt more often than once a trip.

First, next to the Cincinnatian I put my years collecting the Lower and Middle Devonian of New York in as a close second place for sheer variety and quality.

Now back to those pesky "Platytrophias"... Ugh! Steve Holland, in being thorough, has listed all (or most) the various species of that genus which is now called Vinlandostrophia. That list is made up of many species that are the product of a "splitter". Eula McEwan (1919) who created species from the most subtle differences in the various Platystrophias of the Cincinnatian. Combine that with the other "species" erected by some of the less well known members of the Cincinnati School and the list is long. I have an ancient bound copy of the paper by McEwan and it is trouble with a capital T. Several workers have tried to sort them out as best they can but from what I understand many of the "types" are lost or otherwise hard to get to. In my years of cataloging I have yet to find a McEwan species I can clearly identify.

And you are right that Bon Well Hill includes some of the most diverse sections in the series. But the Arnheim is quite different than the Waynesville and this would be a place to be careful to note where on the hill a specimen was found.

If you do a publication search for Platystrophia, Vinlandostrophia and Cincinnatian you will get a decent list of references. Many are available online or as hard copies from the USGS.

It was a sea without fishes and you will have to dive in to learn more.

Edited June 25, 2016 by erose

[Ridgehiker]

I'm enjoying this thread.

One of the best field trip reports I've read. Informative and entertaining.

These Indiana specimens are even more fascinating if one steps back and thinks about the age of the Ordovician. Well over 400 million years old but such exquisite quality as if they came off the shelf of a store selling fine ornaments.

We have limited Ordovician exposures in our Rockies but not near the variety of species you have. Our Ordovician brachiopods aren't described in any literature but similar to the genera in Indiana.

The most common Ordovician fossils near us are graptolites which are formed in very different types of deposits.

Re blastoids. Yes, we also find them mostly in the lower Carboniferous ( Mississippian). They are feast or famine. Find none or find a half dozen sitting together as if they had been placed on a ledge. It's uncanny how much external detail they can have.

[Mediospirifer]

I'm enjoying the discussion, too. It's good to discuss a location I've collected at with others familiar with it! And, yes, I'm learning from this too.

erose: I've seen the first and third of the books on your list, and I have the second. I'll have to pick up a copy of the ones I don't have sometime.

Unfortunately, all I can say about possible strata for my roadcut finds is that I was closer to the bottom of the exposure than the top. On this trip I may have been above the Arnheim when I found my Vinlandostrophia specimens (I found one V. cypha while at the bottom, more V.s only when I climbed up the slope). It's not an easy slope to climb safely, but not as bad as my local shale scree piles!

On the subject of blastoids, I've only found one, in Middle Devonian shale. It's a prized item in my collection. The location I found it at is known for lots of brachiopods, while blastoids are rare.

I should be able to finish cleaning my specimens tomorrow. Photos will come soon after!

[digit]

I'm enjoying that this topic's discussion too. In response to Canadawest's comment--I do my best to make my trip reports entertaining (or at least photo-packed) but in cases like this where I am out of my element, I leave it to others to make it informative.

Looking forward to seeing Mediospirifer's specimens as I'm sure they will be a great addition to show the diversity of what can be found in this outcrop of the Ordovician.

Cheers.

-Ken

[erose]

erose: I've seen the first and third of the books on your list, and I have the second. I'll have to pick up a copy of the ones I don't have sometime.

The first one is still THE main Cincinnatian ID reference for me. I always start there. and it is less than ten dollars. A Sea without Fish is the most current thing written for a more general audience. But it is a hard cover book and priced as such.

Unfortunately, all I can say about possible strata for my roadcut finds is that I was closer to the bottom of the exposure than the top. On this trip I may have been above the Arnheim when I found my Vinlandostrophia specimens (I found one V. cypha while at the bottom, more V.s only when I climbed up the slope). It's not an easy slope to climb safely, but not as bad as my local shale scree piles!

The fourth book will answer many of the questions you would have regarding formations and stratigraphy and most of its chapters are based on actual locations. Pretty sure Bon Well Hill is covered. In fact it is full of locations and descriptions. Again, not expensive.

On the subject of blastoids, I've only found one, in Middle Devonian shale. It's a prized item in my collection. The location I found it at is known for lots of brachiopods, while blastoids are rare.

So far no blastoids are known from the Ordovician of the Cincinnati Arch. But that site at Sulphur, IN is well known for Mississippian Pentramites spp., crinoids, teeth and dermal denticles. Also seem to remember it was crawling with ticks. Ticks on the rocks, not the weeds! The New York Paleontological Society did a field trip that included that site as well as visit to the Falls of the Ohio which is relatively close by.

[Lori LuvsFossils]

Soooo I'm about a year behind seeing this report. LOL Figures!

I was also clued in about the St Leon road cut. I was very clear about my desire to spend an hour there. My driver, however, said I was resting peacefully & didn't want to wake me. We drove right past it! Grrrrrrr

Those rollers are awesome! I'm glad you stopped there & shared the photos. I may be passing that area again later this summer. This time I'll either stay awake or do the driving.

[Mediospirifer]

I'll post some photos tonight, if my computer cooperates! It's being e x c e s s i v e l y s l o w lately, so cropping images and taking photos through my digital microscope are frustrating.

On the plus side, I've got some good ones!

[Mediospirifer]

Finally, I have some photos ready to post! Just the St. Leon findings for now, I have more to do with the other site materials. I'll get to them later.

Here are some hash plates.

Mostly fragments of Isotelus trilobites, Strophomena brachiopods, and some unidentified gastropods. The large gastropod in the center may be a Holopea or a Centronema. I'm not sure which, or it may be something entirely different.

Here are some more gastros, plus a bivalve endocast at right:

I think the large group of gastropods (bottom left) are Loxoplocus bowdeni, while the ones at top are Clathrospira subconica. The small horn-shaped one next t the bivalve may be a partial Cyrtolites. I don't know what the bivalve might be, my reference book is a little thin on mollusks (and I haven't gone digging into online resources yet).

And one of the few bryozoans I can identify on sight: Constellaria.

Notice the starlike pattern on the surface. These critters are cool!

More to come....

[Mediospirifer]

Here's my collection of St. Leon horn corals:

Streptelasma at top, Grewingkia below. There may be a small Grewingkia among the Streptelasma specimens. While it doesn't show in this photo, one of my Grewingkia pieces has a hole bored into it; possibly the ichnofossil Trypanites.

A couple of cephalopod pieces:

My apologies for the poor photo quality. My camera doesn't like taking close-ups, unfortunately.

Here's a bunch of random bryozoans:

Next up, brachiopods!

[Mediospirifer]

Here's a nice bunch of Lepidocyclus:

Most of these are likely L. capax, but there's a group of 4 at top right that aren't as deep in the fold as the lower specimens. The one at middle right is a flatter shell.

Strophomena in bottom row, possible Hebertella in middle row, unidentified fragment at top:

The top fragment shows interesting tooth structure to the outer edge. Also, some of the Strophomena partail valves are quite thick!

And some large trilo-bits:

Most likely Isotelus maximus, or something similar.

More small pieces to come!

[Peat Burns]

Neat finds! Thanks for posting. That bivalve steinkern is really nice.

I think what you have as Constellaria (bryozoan) might be the encrusting coral Protarea richmondensis.

[Mediospirifer]

Here's a nice Flexicalymene retrorsa that my husband found (almost immediately on our arrival!):

Suffice to say, he was pleased! And then disappointed later when it looked like that was the only complete trilo either of us found.

I did find this:

It doesn't quite look like the photos in my book, but I think it's a juvenile edrioasteroid! On a piece of Rafinesquina shell. It's certainly smaller than the edrios I've seen before (at rock shows; this is the first I've found), and I can imagine that the usual structure might develope with size. This one is just under a 1/4 inch across.

One more post for now...

[Mediospirifer]

Neat finds! Thanks for posting. That bivalve steinkern is really nice.

I think what you have as Constellaria (bryozoan) might be the encrusting coral Protarea richmondensis.

Interesting! I'll have to look that one up. I haven't researched the corals of the area yet. I agree regarding the bivalve; I find more gastropods in these areas. Conversely, at home I find more bivalves!

We did find some other good trilo-bits. Here's a trio of cephalons:

And here are two Flexicalymene retrorsa minuens specimens I found that I thought were missing the cephalon:

When I got them home and cleaned the dirt off, I found that they were nearly complete! I think each is missing one free cheek. It's a little hard to tell in the photos because the cephalons are curled under.

I'll post my finds from the other two roadcuts in a few days.

[ynot]