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Tammy and I have been volunteering at the Montbrook dig site in north-central Florida every Wednesday and Saturday for a while. We're part of a small group of local volunteer diggers who've been able to dig the site during the pandemic. We have a maximum of 6 people at the site with 4 volunteers (aka retired people who'd rather not golf or watch daytime TV) and 2 from the museum. Over the last couple of weeks we've worked to take out several gomphothere bones that have turned up in the grid squares that we've been working. Two Saturdays ago we started the jacket on the remaining part of a gomphothere pelvis (the flat ilium was jacketed and removed separately where there was a break in the bone during preservation). It was not dried enough by the end of the day to take that large and heavy jacket out by the end of the day. Some additional plastered burlap was added around the base to make sure the jacket would properly contain the contents when flipped. In addition to the residual gomph pelvis there was what looked to be a really nice alligator skull directly underneath the pelvis which made for a very tall jacket that was also very heavy. With limited crew we flipped that big jacket into the cargo net and (in stages, with rest between) lugged it up out of the pit and into the back of the museum van.


While clearing the area around the gomph/gator cluster so we could encase it in plaster I came across the end (femoral head) of a gomphothere femur. It was toward the end of the day and there was much sand above the bone so it had to wait for another day. We had other obligations this last Saturday and so we could not volunteer that day. Someone in the group digging that day was working down the level of the grid square that the bone looked to be extending into. They didn't get too far as they were distracted by a rhino jaw that happened to be hiding in there. I had been sitting directly on top of it on my previous visit and had actually dropped the level of that 1m x 1m square by about 20 cm (~8"). Had I dug a bit more I would likely have hit the rhino material. This preparatory digging before an interesting find we've dubbed "pre-discovering" a fossil. ;)


With the rhino jaw jacketed and removed we were in position to continue to reduce the level of the sand/clay in the squares around the gomphothere femur. All that was showing when I first happened upon it was the rounded ball of the femoral head and the bulge of bone known as the greater trochanter which serves as an attachment for many leg muscles. We were wondering at which angle the rest of the bone (should it be present) would appear and at what level--the laminated layers of sand and clay dip at a pretty steep slope and bones usually follow the layers.


Tammy spent the early part of the morning digging down from the opposite (distal) end of where the femur should end trying to gauge its length and orientation. When she was coming up with mostly sand she switched tactics to following the bone shaft down from the hip to see where it was leading. I spent the morning taking an adjacent square down about 30 cm (~1') to level out the area in which we were working. Because the layers dip down in this direction (to the east) the sand I was digging in was above the area in which all the interesting fossils started to appear. Occasionally, while digging in sterile sand an odd isolated fossil will turn up. Absolutely none did in this grid square. I was able to remove about 30 of the large plastic kitty litter pails of sand without being bothered with any pesky fossils getting in my way. :P


Once I had my corner square dropped to an appropriate level I started lowering the level of the adjacent square. By this time Tammy had followed the femur to the opposite end. Unfortunately, the preservation on the distal end was not nearly as solid and was instead rather punky--a preservation we've dubbed "pudding bone" which is as problematic as it sounds. This end will require quite a bit of consolidation with the plastic B72 dissolved in acetone to make a stabilizing glue.


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In the left image above, you can see the rounded ball of the femoral head peeking out between Tammy's right hand (with stylish orange glove) and the bright yellow cat litter pail. You can get a better view of the femoral head and the greater trochanter below it on the left edge of the bone as well as the extent to the more crumbly distal end in the right image above.


At this point we knew the size and orientation of this bone and had started to remove higher material around the vicinity so we'd have room to jacket it and flip it over when removing. I started working down the higher corner visible in front of Tammy to the left edge of the left image above. This was still mostly soft (and very easy to dig) sugar sand with some thinner clay layers and chunks of orangish clay nodules. While lowering this area and making room so we could start trenching around the bone to make a nice pedestal for the jacket I found my first fossil of the day. Digging most of the day in sterile layers is necessary work but often does not result in a full bone bag at the end of the day. I've dug many days when no label for my disused bone bag had to be written up. I'd been digging since 10:00am and it was now around 3:45pm (we clean-up and leave at 4:00pm) so it was a little late in the day to be uncovering my first find of the day. This one was worth the wait though as I spotted the gleam of orange that can sometimes herald good news. Of course, 99 times out of 100 the orange is just one of those sticky clay nodules that get dug out and tossed on the spoil pile with the rest of the sand. This one was a faintly different shade of orange and indicates mammal tooth (for some reason mammalian tooth enamel often preserves as a dull orange at this site).


The orange was on a small clump that freed itself while I was digging through the loose sugar sand. Closer inspection with a dental pick revealed the gleam of enamel and not sticky iron rich clay! A little water from the hose was able to soften the sandy clay around it and my first (and only) find of the day turned out to be a really sweet and absolutely tiny baby gomphothere molar. :D This one got slipped into a protective vial that we use for more delicate specimens and was padded with bit of tissue.


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While trying to finish up a bit more of the trench I was digging around the femur I hit some more bone right at the corner of the 4 grid squares which we mark with little orange wire flags. At this point it was really too late to do more work on prepping this for jacketing and that task would fall on anyone working the area Thursday or Friday. If nobody ends up working that square before Saturday then Tammy and I will be back to complete trenching so we have a pedestal that we can jacket.


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With the end of the day's digging rapidly approaching we protected the exposed bone with some empty sandbags till the next time it receives some attention. You can see below the squares I was working as my mild OCD drives me to leave my work area with sharp crisp walls and corners and flattened bases. ;)


Only 1 bone in my bone bag--but I'm quite happy with that.







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That is awesome Ken! Congratulations on that Gomp tooth!

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Between this tooth and the earlier mastodon jaw with teeth in situ, I've been on a roll with hose-nose molars. ;)






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