Archimedes Bryozoan Fossil with Holdfast

Here is a rare example of an Archimedes sp. bryozoan fossil with part of holdfast (root like structures) exposed. It was used to anchor it to the seabed. Another rare feature is the part of the netting or mesh structure that extended out into the water along the edge of the creature's screw shape. The name for water pump screw credited to the Greek engineer Achimedes of Syracuse (287-212 BC).

The naming of this genus is credited to Indiana's first state geologist David Dale Owen (1807-1860) to his publication, A Geological Reconnoisance and Survey of the State of Indiana in 1837 and 1838 in 1838. He later wrote an article for The American Journal of Science and Arts, Volumes 43-44 (1842) entitled Regarding Human Foot-Prints in Solid Limestone. He writes "characterized by a very remarkable fossil coralline, resembling the Retepora of Lin., but verticillated spirally like a continuous screw; described by Lesueur under the appropriate name of Archimedes.*" He writes that on page 19 with a foot note listing, "I am not sure that Lesueur ever published his description of this fossil; but I know that while he resided here (at New Harmony) he engraved a plate containing several views of it, with that intention. He considered it, I believe, a new genus; but it may be only a new species of Retepora; if so, most aptly entitled Retepora Archimedes."

Owen is referring to the French naturalist Charles Alexandre Lesueur (1778-1846). He lived at New Harmony Indiana from 1826-1837. He was good friends with Thomas Say who named the Pentremites blastoid fossil genus and is buried at New Harmony.

The fossil pictured above was part of the James Conkin collection. This bryozoan existed in the Mississippian Period, the genus died out in the Permian Period. No locality was listed with this fossil but I am guessing it was found in Indiana or Kentucky. Thanks to Kenny for the picture.

Ultrasonic Cleaning of Fossils

Late last year I bought an ultrasonic cleaner from a seller on Amazon.com. One of the uses for it was to clean fossils. After trying it out on coins and jewelry, I did not much difference in the before and after and shelved it. I think some of my issues though were in my process and the items I was trying to clean.

So this weekend I tried another coin and it seemed to clean it up quite a bit. The change (so to speak) I made in the process was using distilled water and heating it before hand in the microwave till it was coffee hot. I then added about 4-8 drops of Dawn dish cleaner to the water. Set the cycle to 480 seconds. Once complete, removed the basket and rinsed the specimen in tap water. Then brushed it with soft bristle tooth brush. Put the specimen back in the cleaner for another 480 seconds. Repeated this process until it seemed cleaner than before I started.

Above you can see the Devonian Period fossils I started with. A couple branching corals, button coral, and some crinoid holdfast stems.One can then observe what they looked like after I finished. The water was quite muddy looking at the end of the process. While not perfect, it was definitely an improvement.

Below is a link to the cleaner I was using. If you are interested make sure you read a sampling of the comments as they are a mix of works great to does not work at all. I experienced both cases of this and I think it depends on what you are trying to clean and the process you pick for the workflow of cleaning. I have since cleaned a number of brachiopod and blastoid fossils with good success.

Magnasonic Professional Ultrasonic Jewelry Cleaner with Digital Timer for Eyeglasses, Rings, Coins (MGUC500)

I am also experimenting with small Bissell steam cleaner though I need a way to hold the fossil in place while cleaning with this. Inspiration for this came after watch the BBC show The Repair Shop on Netflix. They use a wand like steam cleaner on ceramic items with amazing results. This type of device is especially good at getting dirty out of crevices and cracks. If I get good results using it on fossils I will make a posting about it.

Neuropteris Plant Fossil from Kentucky

This fossil appears to be a Neuropteris plant fossil. It was found in Perry County Kentucky, USA. The fossil dates to the Pennsylvanian Period. Scale is in centimeters.

Thanks to Kenny for the image.