Thursday, September 30, 2010

Calymene Update

This post is an update on a Silurian Period Calymene trilobite fossil I have been preparing.  This first image shows a lot more of the sides of thorax exposed with large chunks of the matrix removed.  The pygidium has been sandblasted mostly clean.  A new tool was used to remove large sections of surrounding matrix.  A Dremel tool with a circular cutting disc attached made short work of the shale matrix.  Looking at the picture the left side displays evidence of a cut line.

The picture above shows the trilobite at head level with more of the lower thorax showing.  A Dremel engraver was used to accelerate removal of this material to complement the engraving needle.  The engraver is a somewhat risky tool to use as the fossil could shatter or start to crack.  For the most part used successfully, a crack has appeared under the center of the cephalon right above the matrix.  Looks like I will need to super glue it to stabilize that section.

 Overhead view of the trilobite after it has dried.  Notice the cut lines from along its outer borders.
 Close up view of the pygidium and left side thorax lobe.  Part of the side thorax chipped off when the matrix was being cut.  It was super glued back on.  Also a small thorax ridge segment broke off when the needle tool was being used earlier and it was super glued back on.  The sand blaster seems to have removed evidence of excess glue around those parts.

View of trilobite's right side with the matrix under the cheek and eye removed.

Thanks to Kenny for letting me use the sandblaster and with the idea of using a Dremel cutter.  Also suggesting I start using the engraver more to help remove the large amounts of matrix around the front of the cephalon.  It uncovered a pyrite ball on the left side that took some time to break out!

Wednesday, September 29, 2010

Eryops Amphibian Fossil



This fossil of an adult Eryops displayed at the Smithsonian Museum of Natural History (August 2010).  The creature is an ancient amphibian that existed in the Early Permian Period (270 million years ago).  Fossil was found in Texas.


Tuesday, September 28, 2010

National Fossil Day Art Contest 2010


National Fossil Day (in the United States) is coming up on Wednesday, October 13, 2010.  What I was not aware of until reading David Orr's informative blog, Love in the Time of Chasmosaurs, September 25, 2010 entry is that there is also an art contest. 

One entry per person and its due by October 5, 2010.  See all the info about the contest at this web site.

Monday, September 27, 2010

Fossil Prepping Update on Trilobites


The Calymene trilobite that I documented over the weekend has more of its left cheek exposed.  I have suspended work on it as the needle tool handle has blistered my hand making it painful to use.  Once my hand heals up, I will continue to try and reach the bottom ridge line of the cephalon.



Kenny has finished prepping the Trimerus trilobite pygidium.  It looks great!



Sunday, September 26, 2010

Progress on Calymene

Over 400 million years ago, the muddy seafloor stirred below a deep tropical sea.  Slowly, the armored headplate of a multi-segmented creature emerged from the muck.  Today the fossilized remains of that creature is slowly emerging from its stony grave... behold the Calymene trilobite.



Yesterday, the matrix with this fossil was profiled today more of the remains are revealed.  Using a dissecting needle, toothbrush, water, and gentle prodding the matrix is slowly being removed to expose more thorax and cephalon detail.  The pygidium is hanging over the matrix so pressure applied there could snap it off.  That section will need to be abrasive cleaned.  Trilobite is a little over 5 cm long.



Here is a close up of the cephalon section.


Saturday, September 25, 2010

Calymene Challenge


It appears this is a complete Calymene trilobite of the Middle Silurian Period.  It is about 5 cm long and will be a challenge to coax out the matrix.

Friday, September 24, 2010

Catch a Trimerus by the Tail

The Trimerus delphinocephalus trilobite of the Silurian Period. This first image is from a 1910 book. The picture is to give you an idea of what the entire trilobite looked like. Today's highlighted fossil is just a fragment of one of these trilobites (the rear section or pygidium).

Trimerus delphinocephalus (Green)
North American Index Fossils by Amadeus Grabau & Hervey Shimer
Volume II, 1910
Trilobite found in Niagaran of New York, Ontario, & Indiana
Image from page 317

This is a beautiful fossil fragment just recently found in the Waldron Shale of Clark County, Indiana.  Select the image to see a larger version and note the detail still left on the fossilized outer shell.  It has such a beautiful color.  Preservation is such that one can run their finger over the shell and feel the bump/segment details. The fossil needs a little work with an engraver and sand blasting of little bits of matrix.



See an intact one on the Dry Dredgers web site found in New York.

Thanks to Kenny for letting me photograph this fossil.

Thursday, September 23, 2010

Jurassic Period Acanthoteuthis


This squid fossil found in Germany lived in the late Jurassic Period (145-140 million years ago).  The prominent cephalopod in the Mesozoic Era were the ammonites but today squids dominate the seas.  This fossil has been identified as an Acanthoteuthis sp.  It is displayed at the Smithsonian National Museum of Natural History in Washington D.C. (August 2010).

Wednesday, September 22, 2010

Parkinsonia dorsetensis Ammonite

Parkinsonia dorsetensis ammonite fossil found in England.  The creature lived in middle Jurassic Period (174-164 million years ago).  Specimen on display at the Smithsonian Museum of Natural History (August 2010).

Tuesday, September 21, 2010

Eucalyptocrinus elrodi Calyx

Bottom of an Eucalyptocrinus elrodi crinoid calyx with a partial covering of pyrite crystals.  Found in the Waldron Shale of Clark County, Indiana.  This crinoid existed in the Middle Silurian Period.

See a prepared E. elrodi  found in St. Paul, Indiana at Crinus's fossil web site.

See more examples of this species at the Weeks Trilobite site.

This particular species is not quite as common as the Eucalyptocrinus crassus which is an index fossil for this formation.

See the Weeks Trilobite web site for more examples of the Eucalyptocrinites crassus.

Crinus fossil web site also has an E. crassus pictured found in Sellersburg, Indiana as well as a holdfast found in Waldron, Indiana.

This fossil was sandblasted -- thanks Kenny!

Monday, September 20, 2010

Glyptambon Trilobite


Trilobite cephalon found in the Waldron Shale.  Middle Silurian Period was the age this creature lived.   It appears to be a Glyptambon verrucosus? Fossil found in Clark County, Indiana.  Fossil is somewhat small with cephalon being approximately 1.75 cm wide.

See Weeks Trilobites web site for a truly stunning specimen of this species of trilobite!


Sunday, September 19, 2010

The Trilobite Spiral




The Smithsonian Museum of Natural History of Washington D.C. has an extensive collection of Ohio trilobites on display.  It consists of three spirals that show the grow sizes of three common trilobites: Isotelus (Ordovician), Flexicalymene (Ordovician), and Phacops (Devonian).  They appear to be from Ohio and presented in an enrolled state.




Friday, September 17, 2010

Paradichocrinus planus Crinoid

Paradichocrinus planus crinoid calyx found in Indiana.  It existed in the early Carboniferous Period (345-325 million years ago).  Picture taken August 2010 at Smithsonian Museum of Natural History, Washington, D.C.

Thursday, September 16, 2010

Fossil Festival 2010

If you are any where near Louisville, Kentucky this weekend (September 18-19, 2010) stop by the Falls of the Ohio State Park's 16th Annual Fossil Festival.  Learn more at their web site: http://fallsoftheohio.org/FallsFossilFestivalProgram.html

I will be giving a presentation Saturday on Fossils and the Internet.  A short presentation about different websites on the Internet pertaining to fossils.  The image above is a sheet, entitled "Fossils of the Waldron Shale".  I created it to help visitors identify the fossils they can find in the Silurian aged rock pile at the edge of the parking lot.  There will also be piles of dirt to find Devonian fossils and fluorite minerals from Illinois.

If any one would like a PDF version of the Waldron Shale Fossils identification page, e-mail me at louisvillefossils@gmail.com.  The Blogger software does not let me post PDF files.

Silurian Scolecodont

This is my first find of a scolecodont in the Waldron Shale of Clark County, Indiana.  It was found while studying a slab for graptolites after seeing an iridescent (rainbow) pattern in the sunlight being reflected into my loupe.  The hook like shape is a visual signature of some scolecodonts. 

This Waldron shale breaks down in water quite easily and after isolating the fossil from the slab with an engraver, dental pick, pen knife, and spray bottle.  The shale flake containing the fossil was put on a microscope slide and these images were produced.  I used a needle tool to move more matrix from the fossil which revealed how fragile it and the matrix was.  The scolecodont had cracks and pieces did break off after being separated from the majority of the matrix.  This fossil is not a resilient as the Ordovician ones I am use to working with.  My intent was too look for the serrated edge that runs along the top of the fossil.  It was found at 100x magnification (though not very photogenic).

Unsure about its name and I have not really researched Silurian Period scolecodonts before.  Most of the sources I know are on the Ordovician ones found east of the city.


The 100x images are somewhat blurry but the serrated edge is intact on this fossil (just very small).

Wednesday, September 15, 2010

Cambrian Monoplacophorans


Fossil monoplacophorans displayed at the Smithsonian Museum of Natural History in Washington D.C.  These fossils are from the Cambrian Period (570-500 million years ago) and were found in Missouri.



Tuesday, September 14, 2010

Priscacara clivosa Fish Fossil


The fish fossil Priscacara clivosa found in Wyoming (probably Green River Formation).  It lived in the Early Eocene (50 million years ago).  Picture taken in August 2010 at the Smithsonian Museum of Natural History in Washington, D.C.


Monday, September 13, 2010

Forbesiocrinus multibrachiatus Crinoid

This crinoid calyx with a long stem piece attached is the Forbesiocrinus multibrachiatus.  Existing in the early Mississippian Period (345-325 million years ago, Osagean stage) and found in Indiana (probably Crawsfordsville, Edwardsville Formation).  Fossil image created in August 2010 at the Smithsonian Museum of Natural History in Washington, D.C.

Sunday, September 12, 2010

Anastrophia Brachiopod


Waldron Shale brachiopod found in Clark County, Indiana.  The creature existed in the Middle Silurian Period.  My best guess as to its identification is the Anastrophia.  If one looks at the third picture, showing it from a hinge view it has been compacted.  Refer to the Indiana State Museum collection record for this genus.