David Cox III

  • 5 days, 20 hours ago
    David Cox III posted an update in the group Vacation Explorers

    The attached photos show a specimen I picked up in a rock shop in North Carolina many years ago.  They said it was from Pennsylvania or Ohio if I remember correctly (I could be mistaken).  Anybody have any thoughts on what it might be?  Sorry for the glare in the phone photos.  I can take more with an SLR if need be.  Thanks.






  • 1 week, 3 days ago
    David Cox III posted a new activity comment

    Were the ants invited guests or did they party crash?

  • 1 week, 3 days ago
    David Cox III posted a new activity comment

    megalodon and gompothere.

  • 1 week, 6 days ago
    David Cox III posted a new activity comment

    Thank you!

  • 1 week, 6 days ago
    David Cox III posted an update in the group Nebraska Badlands

    View across the Nebraska Badlands as a storm builds.



  • 3 weeks, 3 days ago
    David Cox III posted a new activity comment

    Who is this bird you speak of? Wren from Carolina or Virginia Rail? One must be careful, Red is knot the one you should listen to. When Brandt and that loon Jay get together there are some tall tails. Cliff’s stories are hard to swallow. Was Phoebe telling the truth or just parroting Myna? Townsend will warble more than he knows, like his friend Magnolia. You can trust Ruddy, he will leave no stone unturned. A cardinal principle is to watch what this flock does. Talk is chirp.

  • 3 weeks, 6 days ago
    David Cox III posted an image in the group Florida’s Fossils from the myFOSSIL app

    End view of turtle shell showing interior structure. Bone Valley Formation, Polk County, FL

  • 3 weeks, 6 days ago
    David Cox III posted an image in the group Florida’s Fossils from the myFOSSIL app

    Here are some better photos of the larger piece. The inside structure is really interesting

  • 3 weeks, 6 days ago
    David Cox III posted an image in the group Florida’s Fossils from the myFOSSIL app

    Turtle shell pieces from Agricola Mine, Polk County, FL. Bone Valley Formation #fossil

  • 4 weeks ago
    David Cox III posted a new activity comment

    The labels look like they came from a fossil company that used to sell mail order in the late 1960’s. I can’t remember the name of the company, but they did have pretty good data on their specimens. I want to say they we out of Texas, but I could be mistaken.

  • 1 month ago
    David Cox III posted an image in the group Bookworms from the myFOSSIL app

    Fossil collecting in the American West in the late 19th and early 20th century. What Sternberg was able to accomplish was amazing. #fossil #method

  • 1 month ago
    David Cox III joined the group Bookworms
  • 1 month, 2 weeks ago
    David Cox III posted a new activity comment

    Fossils of Gumby? I’m not dating the specimens, but I might be dating myself.

  • 2 months, 1 week ago
    David Cox III posted a new activity comment

    Barracuda?

  • 3 months ago
    David Cox III posted a new activity comment

    or one on Mesozoic trees called “Jurassic Bark”

  • 3 months, 1 week ago
  • 4 months, 1 week ago
    David Cox III posted a new activity comment

    Mike, thanks for the great explanation. Very thorough. I look forward to hearing the results.

  • 4 months, 1 week ago
    David Cox III posted a new activity comment

    Mike, could you give a bit of detail on what we are looking at in this photo? How is a paleomag sample collected and prepared? Just the very basics would be great. Thanks.

    • Of course! Montbrook paleomagnetism sediment samples were collected throughout the section to compare results from the top and bottom. All sample orientations were recorded in the field as well as on the sample themselves (that’s the black arrow you see on the pictured sediment). Since we all know how crumbly the sand-dominated Montbrook sediments can be, a heavy coat of lacquer was applied to harden the sample as well as ‘lock’ in the position of sediment grains. Back in the lab (in this case, my garage), a diamond tipped rock saw is used to cut the larger samples into smaller ~2.3cm cubes (standard size for the machinery used to conduct paleomagnetic analysis). Ideally, each larger sample will be worked into 4 of these smaller cubes. Cubed samples are wrapped in tin foil for rigidity/protection while they are being stored!
      -3 cubes are prepped to determine remanant paleomagnetic orientation, so it is essential that the direction of the black arrow from the larger sample translates over into these smaller samples. Why 3 samples? At least three samples are needed for analysis in order to be statistically significant. As with most things in science, the more repetitions/tested samples we can get, the better!
      – 1 other sample is prepped and designated for composition analysis in order to test what minerals within the Montbrook sediment lend themselves to magnetization (ex: hematite/magnetite).

      All in all, I have about 50 samples prepped. Paleomagnetism will not give us an exact age, but it is a great method to support the site’s estimated age which has been suggested strictly through vertebrate biochronology. With any luck, we may see a reversal in earth’s magnetic poles from the top of the geologic sequence from the bottom. If so (fingers crossed), this can be compared to well-documented magnetic records from the Late Miocene to further constrain the age of Montbrook!

  • 4 months, 1 week ago
    Max Jones and David Cox III are now friends
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