Mesozoic

Another wonderful day on the river! Weather forecast called for a cold front to come in, but we were far enough south to enjoy very nice weather. The river had risen 10-15 feet since the scouting crew checked it out the previous week, and much of our collecting area was under water. The collection area is in the marl limestone sequences in the Arcola Limestone Member (Late Cretaceous Campanian 83-74 mya). We were hoping to find more of "our" mosasaur, whom we have named "Bigbee", and we actually did find one piece, another vertebra, in situ. Much of the collecting area had been scoured by the water and wave action. A few other pieces of mosasaur bone were found, including one vertebra, but not in the same area as the ones from the last trip, so there is no way to be certain they are from the same animal. Numerous steinkerns (internal molds) of gastropods (snails), bryzoan (look like a bunch of worm tubes stuck together), brachiopod, pelecypod, straight cephalopods, and ammonites were found, also some carbonized fossil wood.

Steve was spotted tooling around in the boat, looking as if he planned to go way down to a place that was difficult to walk to, so Vicki stuck out her thumb and she and Paige hitched a ride. A very exciting time getting into that boat from a cliff face! Claire decided not to try the boat trick, but decided to risk walking along the steep bluff. We got there about the same time, and of course were looking for "great treasures". Vicki spotted something that looked "odd" pretty quickly, and it turned out to be part of a large ammonite embedded in a huge boulder that everyone had walked past. We all started hunting around that area, but didn't find the other half. Further down, Steve stuck his hammer up under a rock before putting his hand there to check for fossils. Good thing he did, because a cottonmouth attacked the hammer! After moving away from the snake, we heard Claire squeal. She had found another large ammonite near where the first one was found, and it was almost complete. Steve just shook his head, and declared he would never pick up hitch-hikers again!

A small group took off on a scouting expedition after the trip was officially over. They found a nice shelf area with numerous fossils which were very fragile and easily breakable. So, we'll just enjoy the pictures! Found a number of very nice ammonites, a few shells, and pieces of fossil wood.

A big THANK YOU goes to Captain Gilbert and Captain Steve for the use of their boats!

(pictures courtesy Lea Martin, Claire Smith, and Vicki Lais.)

Hanging out waiting for everyone to arrive.

Paige, Leisa, Gilbert, Carl & Vicki popping out the small gastropods and straight cephalopods.

Claire is just getting started.

Mosasaur vertebra found by Vicki, quite a distance from the others that were found on the last trip.

Leisa excavating around a fragile fossil.

And the nice gastropod she collected.

The chalky shoreline. (Paige isn't tired, just getting a closer look!)

Steve's attention has just been diverted as someone stopped to talk . . .

Close-up of some of Steve's finds, mostly gastropods. There is also a nice mosasaur bone in that box.

Tiny nautiloid found by Steve.

Several Exogira were found.

Some of Lea's finds.

Some of Paige's finds.

Gilbert has found another one (what, I don't know!)

Nice gastropod and the impression it left in the chalk, found by either Lea or Paige.

Nice partial ammonite in place. It really blends in with the boulder quite well. Several people passed by without spotting it, leaving it for Vicki to find!

Same ammonite after excavation. This is the bottom that was protected from weathering.

Paige holding an ammonite found by Claire.

Carl showing off his favorite finds.

Captain Steve and Captain Gilbert. Thanks, guys!

Gilbert found some fossil carbonized wood and a mass of what is either worm tubes or bryozoans.

Another nice gastropod and image it left in the chalk.

Shells embedded in the chalk.

Carl & Leisa, tuckered out after a long day.

Steve's finds, all cleaned up and protective coating applied.

Nice Ammonite found by Claire (after cleaning)

Another view of the ammonite.

A limestone shelf filled with fossils found in the late evening. Nice to look at, but the fossils were too fragile to collect. Below is our "picture collection".

Nice ammonite.

A limb of carbonized wood.

Another nice ammonite.

October saw the troops headed to Hale county, AL to a favorite creek. After meeting at a rest area, we headed South to Tuscaloosa where we made a stop at the Museum of Natural History on the University campus. Great fossil collections as well as a fun exhibit of bugs and bats caught everybody's interest. We were delighted to see that the Mosasaur is still on display. Stopping at the museum gave us a chance to get a visual fix on what we might find during the day, so it was a nice start for the day.

 

 

Another boat trip, this time in Sumter county, at a river site with huge chalk bluffs.  (The lake level at the Demopolis Lock was 74.28 feet above sea level).  The fossils we collected are from the marl limestone sequences in the Arcola Limestone Member (Late Cretaceous Campanian 83-74 mya).  Last year, Dr. Charlie Smith, who has done many years of research on this site, came with the group and provided a wonderful lecture and handouts to the group.  This year we found a number of straight cephalopod segments, gastropods up to 6cm in diameter, fish dermal spine, and ammonite pieces.  But the real prize of the trip was several mosasaur vertebra found in three separate "piles" in a 15 foot area along the riverbank.  Vicki found the first fossil vertebra, which was standing on end, and had only the top exposed.  After convincing Greg to come look, there were decisions to be made.  Do we leave it here in place and take the chance of the river rising and washing it away?  We noticed this area had been under a heavy layer of pea gravel the last time we were here, and the pea gravel had disappeared.  Do we trench it and extract the bone, or use a plaster jacket over the whole thing?  The decision was to take the bone out, not take the chance on having it wash down the river, and protect it with a plaster jacket.  However, after excavating around the bone, it was discovered a small but sturdy piece of the chalk could be extracted, making the plaster jacket unnecessary.

As Bobby came over to see what all the fuss was about, he saw "odd shapes" sticking out of the chalk about 15 feet before he got to where Greg was working, and after looking closely, realized it was several more vertebra.  Steve came over to assist in excavating this new pile of bones.  The other part of the group had gone to another nearby beach, and were basking in the sun (and I suspect they went swimming based on Nancy's drenched appearance!).  They decided to ride back over after all the hard work had been done, and see what we had found.  Then Jan asked if we had looked under that tree trunk beside us.  Well, no.  So the trunk was moved, and low and behold, there were about 5 more vertebra under it, which were also excavated.  So this was truly a group find, and everyone got to work on the excavations, initial cleaning, and proper packing.

Bill, with the assistance of Leisa, did a great job on the site survey and drawings.  Greg, who worked many years with the paleontologists at Red Mountain Museum, supervised the excavation and has been preparing the fossil bones for display.  Thanks to all for the fine work and photos!  (NOTE:  any professional paleontologist who desires to study these fossils, please send your request via email.)

Afterwards, a number of members went to another river site in Sumter county to collect marcasite.

Bill Cunningham also contributed to this report.

(Photos courtesy of Nancy Kenfield, Bill Cunningham, Vicki Lais, and Greg Mestler.)

WOW ! 

(Click images for larger view.)

Lets get going!

   

Hey, guys, pose for me!

In large photo above, this is the leftmost vertebra, immediately after excavation. 
   Top view of vertebra.

Bottom view. 

   

One of the many gastropods found. 

What did you find?

Vertebral column extends 7 meters from near Coke can to several feet beyond the excavators.

Yes, we get dirty.

The excavation site had a small drainage problem...

Samples of typical finds - ammonite, straight cephalopod, gastropod, turritella, limpet, oyster.

Steve with his latest treasures.

Bobby washing mud off the vertebra.

Group of eight vertebra.

Three vertebra in situ (about 15cm apart)

A vertebra in matrix (caudal concave discoid about 5cm)

Ammonite impression (about 30cm)

Local wildlife.

Water hyacinths are pretty, but is an invasive species that destroys our rivers and lakes, and it is prohibited to sell it in the state of Alabama.  Thick infestations can make boating or swimming impossible.

Several members traveled to another Sumter County location to collect marcasite.

White chalk cliffs in Sumter County, AL.