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Classic Localities in the Alabama Cretaceous and Paleogene


MikeR

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Going back several decades I have attempted to have an annual extended field trip; call it a fossil collecting vacation.  Some years this happens, some it doesn't but this past November I had the opportunity to spend several days in the field visiting some of the classic Cretaceous and Paleogene river sites which abound in Alabama.  Since I haven't had the opportunity to post much in my blog, I decided to post pictures from that trip here as I have time.  First up are pictures from the lowermost Maastrichtian (~70 mya) Upper Cretaceous Bluffport Marl Member of the Demopolis Formation.

 

The Demopolis Formation for the most part is a Campanian aged chalk however the Bluffport Marl Member which defines the upper portion of the Demopolis is a molluscan rich sandy lime lying within the Exogyra cancellata zone.

 

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Aragonitic shells have not been preserved however calcitic oysters are abundant including Exogyra cancellata, Pyncodonte convexa, and Paranomia scabra.

 

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Rarer elements include Exogyra costata and iron/hematite(?) pseudomorphs of Trigonia sp.

 

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Temperatures were near perfect in the lower 60s and when not collecting it was a joy to watch the ever present barges on their way to Mobile.

 

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Mike,

 

Hope you had fun and found lots of cool fossils. Have to say, that is an awesome looking boat in the last picture. Looks like a barge in its own right. Not too sure about that guy in the blue shirt striking his "Capt. Morgan's" pose though. He looks kind of like a cranky ole boat driver I know from southern PA. ;-)

 

Hopefully, we can get together sometime in the near future and do some hunting/collecting.

 

Cheers,

 

Jack and T

Don't know much about history

Don't know much biology

Don't know much about science books.........

Sam Cooke - (What A) Wonderful World

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Jack--I have to agree with you about the boat and the captain.  :)

"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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The youngest Cretaceous deposit in Alabama is the 67 million year old Prairie Bluff Formation.  We visited a famous site that exposes the Alabama KPg from which several papers have been published claiming the large blocks between the Prairie Bluff and the Lower Paleocene (Danian) Clayton Formation were formed by a Tsunami from the Chicxulub Meteor impact.  This claim is discounted by many professionals as foraminfera dates each formation here as mid-Maastrichtian and mid-Danian and while the blocks do show that something powerful tore up the ocean floor at that time, the mixture of Cretaceous and Paleocene fossils discount Chicxulub.  

 

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Unlike the Demopolis Formation which is sparsely fossiliferous, the Prairie Bluff Formation contains a rich and diverse fauna.  Although fossils can be found throughout, a one foot lag layer contains the highest distribution.

 

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Prairie Bluff mollusks are preserved as internal casts and include gastropods such as Gyrodes and Anchura; the cephalopod Eutrephoceras dekayi, ammonites Discoscaphites conradi, Trachyscaphites alabamensis, and Baculites; echinoids and others.  The Clayton here contains small oysters and the Lower Paleocene cephalopod Hercoglossa ulrichi.

 

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Unlike the previous site containing friable marl forming nice beaches, the resistant chalk of the Prairie Bluff produces high banks making the waves from the barges more hazardous to collecting.

 

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Hey Mike, nice to see the stratigraphy and finds. I'll have to go read some of those papers about the boundary there--thats a fascinating topic that I dont know much of anything about. I'm definitely intrigued about the Trigonia and the Baculites. Not sure what it is about Trigonia...I think it was a photo (actually must have been a drawing---I'm dating myself) of one I saw in a book as a kid that hooked me with that diff ornamentation. Curious, do belemnites show up anywhere? 

 

Thanks for the trip shots. Regards, Chris 

 

 

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6 hours ago, Plantguy said:

 Curious, do belemnites show up anywhere? 

 

Belemnites definitely occur in the South Carolina PeeDee.  One of the Alabama Geological Survey scientists told me of a nearby Ripley site with belemnites however I have yet to check it out.

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Thanks for the travelogue, I'm looking forward to the rest of it.  

 

Those are really nice suture lines on that Hercoglossa!  I collected three at that site a couple of years ago, but none have the suture lines as nicely displayed as yours does.  Also, what is the right-hand specimen in your Prarie Bluff assemblage?  Is that a big Trachyscaphites?  That's a sweet Eutrephoceras; I found a small complete one and several larger fragments.

 

Don

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1 hour ago, FossilDAWG said:

Those are really nice suture lines on that Hercoglossa!  I collected three at that site a couple of years ago, but none have the suture lines as nicely displayed as yours does.  Also, what is the right-hand specimen in your Prarie Bluff assemblage?  Is that a big Trachyscaphites?  That's a sweet Eutrephoceras; I found a small complete one and several larger fragments.

 

Very astute Don!  You are correct that the suture patterns on the H. ulrichi are not as defined from this site as that which I posted.  The pictured specimen is from an exposure of the McBryde Limestone Member of the Clayton Formation in Butler County.  The hardness of the McBryde seems to preserve the casts better which is exactly why I took a photo of this specimen and I should have noted it in the post.

 

Yes I do believe the larger of the two ammos is Trachscaphites and as to the gastropods I have yet to work on any of the material from my three trips to the site.  Norman Sohl's USGS professional paper monograph deals with the Prairie Bluff so I should be able to tell you once I have the opportunity.

 

Mike

"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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2 hours ago, Ludwigia said:

Great report! Looking forward to more if it's still coming along. Could it be that your Trigonia is a Myophorella?

There is more to come.  

 

The Upper Cretaceous Trigonids in the Southeastern United States have been traditionally designated Trigonia however some have been reassigned as Pterotrygonia.  Myophorella might be restricted to Eurasia.  A quick review of Akers and Akers (2002) does not show Myophorella present in Texas.  Trigonia and Myophorella are related but only at the order level (Order Trigoniida).

 

Mike

"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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I know that they're from the same order. That's why I was thinking along that line. Funny that they don't occur there. Is the morphology so different? It sure does look like a typical European Myophorella at first glance.

 

Greetings from the Lake of Constance. Roger

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Besides football, Alabama is famous for the number of classic Paleogene localities exposed upon its coastal plain.  These unconsolidated siliciclastic sites can easily be collected yielding mollusks as old as 70 million years old which appear as if they were picked up from a beach.  The oldest of these sites that we visited was the type locality of the Bells Landing Member of the Tuscahoma Formation.  This Upper Paleocene deposit is equivalent to the Aquia Formation in Virginia containing many of the same species but more diverse due to its southern latitude.  Collecting consisted of digging into a 2-foot molluscan rich layer composed among other species Turritella postmortoni, Calyptraphorus trinodiferus, and Ostrea sinuosa.

 

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Below is an example of some of the shells that I have found on previous trips and a sunbathing local encountered on this trip.

 

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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1 hour ago, FossilDAWG said:

Wow, I really need to get to that site.  Those shells are immaculate! :wub:

 

Don

 

Anytime you want to pull out that canoe of yours, I'll take you there.

"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Another classic site in Alabama is the type location of the Lower Eocene (Cusian) Hatchetigbee Formation.  

 

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In his epic monograph on the Paleogene fossils primarily from Alabama, Lyman Toulmin described three fossiliferous beds at this location; Bed A at water level with large Crassostrea sp., Bed B with many Venericardia hatcheplata, and Bed C with a diverse open water marine fauna.  When I first collected this site in the early 90s Bed C was still exposed however it is now largely slumped and covered.  The first picture below is of Bed A followed by various shots of Bed B.

 

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Large double-valved V. hatcheplata in life position are incredibly abundant however careful search of Bed B will yield nice gastropods.

 

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Wow.. Some of you other Forumers have some easy collecting.

 

Strange how everything from the Paleogene and Neogene look like they were buried last year. My local Cretaceous shale looks the same as stuff from the Paleozoic (in terms of preservation). Some of your Cret material looks pretty new and easy to collect too, but some of it is steinkerns.

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One of the more widespread Formations within Alabama is the Upper Lisbon Formation and on this trip we visited three different exposures of this Middle Eocene deposit.  The first of these another one of those classic Alabama localities contains a rich molluscan fauna.  A rich layer of the bivalve Venericardia densata is present but other species are also contained in the dark gray marine clay/sand.

 

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Downstream at the sinister sounding Rattlesnake Bluff a layer of very large Ostrea sellaeformis lie within the lower portion of the Upper Lisbon shown in the photo of a trip that I made to this site several years ago.

 

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Of all the seven or so Lisbon sites that I have collected, the best has to be at a fault that has brought up Lisbon further down in the formation.  The shells here are beautifully preserved containing among others, large naticids and shark teeth.

 

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Mighty fine photos of the geology and finds. Great to see! So whats going on with the larger elongated? masses in this bed? Are those slumping related? What are they/composed of? 

large masses.jpg

Regards, Chris 

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On 1/9/2017 at 9:05 PM, Plantguy said:

Mighty fine photos of the geology and finds. Great to see! So whats going on with the larger elongated? masses in this bed? Are those slumping related? What are they/composed of? 

 

Regards, Chris 

 

They are large sandstone concretions which have fallen from higher up in the bluff.

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Gilbert Dennison Harris the founder of the Paleontology Research Institute in Ithaca, NY was reported to have said that if there was a type locality for the Eocene that it would be Alabama.  Much of that would be due to the Gosport Sand, the Middle Eocene unit directly above the Lisbon Formation.  Probably more so than any other Eocene unit, it is the richest and most diverse deposit of its age in the USA with a limited distribution, found only within Monroe, Clarke, Washington and Choctaw Counties.  In the past I have visited four Gosport sites and none are particularly easy collecting.  One of the most famous, Little Stave Creek I began collecting in the 1980s.  Although difficult to get to, once accessed it allowed easy screen wash collecting from a creek gorge shaded by large hardwood trees.  The owner closed the site in the 90s however granted access to the site in 2010 to the Alabama Geological Society which I attended.  The area had been logged and without the large shade trees much of the deposit has become silted over--very sad.  On my November trip we visited three other Gosport sites.  The Baker Hill locality used to be easily accessible by boat however trees have since over grown the bluff and a house built almost on top of the fossil beds.   Gosport Landing is very high in a bluff however in the past I have used ropes to climb to a ledge with very productive collecting.  That ledge has since collapsed and no one was in the mood to climb the bluff so we bypassed the site.  Claiborne Bluff is hit or miss.  Three years ago a massive fall from high in the bluff afforded productive collecting however that is now gone.  This trip we were only able to find a few blocks which we bulked collected.

 

The first picture was taken in November comparing Gosport material (right) to the Lisbon (left).  Next are photos from past trips showing Dr. Lauck Ward pointing up a cliff fall at Claiborne Bluff, sandy beds at Gosport Landing, and the red sand beds at Baker Hill.  Also pictures of Gosport gastropods in my collection.

 

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Transitioning the Middle Eocene to the Upper is the Moodys Branch Formation.  In Mississippi the Moodys Branch is composed of two beds, the Upper is a shell bed with well preserved mollusks which pinches out very quickly past the Alabama line.  The lower member called the Scutella Bed is composed of countless numbers of the irregular echinoid Preriarchus lyelli with a large geographical range within Alabama.  The site we visited in November is unofficially called Scutella bluff where with a little care complete echinoids could be removed.  This unit was also exposed upstream at Rattlesnake Bluff above the Lisbon Ostrea sellaeformis bed.

 

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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These appear to be great collecting sites. Thanks for sharing with us.

Dipleurawhisperer5.jpg

I like Trilo-butts and I cannot lie.

 

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What an incredible field trip report. Its refreshing to have the quality information on the stratigraphy and specimens interweaved through a fun narrative.  

 

We're all drooling. 

 

 

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