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Fossil Collecting

TGMS Member Post by:  Dick Gottfried


Ever since I was a kid I have enjoyed fossil collecting.  I guess I was a frustrated marine biologist. Everyone who majored in biology in college either wanted to be a marine biologist or get into med school.  The problem was that there weren’t enough marine jobs to go around, and since I had flunked out in my freshman year (having too much fun, but that’s a tall tale for another time), med school was out of the question.  I enjoyed collecting and studying biological specimens, but keeping them in bottles of formaldehyde around the house wasn’t of interest to me.  Kinda reminded me of the Frank Zappa song Lets Make the Water Turn Black,  (“...and all the while on a shelf in the shed, Kenny’s little creatures on display!”).

I’ve always enjoyed collecting rocks and minerals, and I discovered fossils when I was about 10 years old. That interest never went away.  Paleontology, or the study of fossils, is actually the study of any thing that ever lived on Earth, at any time, since the beginning of life.  Quite a wide field!  There are over 10 million animals and plants alive today, and many, many times more that have lived and gone extinct in the past.

I’d like to talk about a starfish that I have just identified that I had found in Missouri.  Missouri used to be at the bottom of the ocean, called the Kaskaskia Sea during the Mississippian Period (359 – 323 million years ago).  This specimen was found in a formation called the Fern Glen (Lower Mississippian), which is a reddish limestone, containing horn corals, brachiopods, fish teeth, crinoid columnals, trilobites, and a unique bryozoan known as Evactinopora radiata. 

This is a star-shaped bryozoan that can have from 3 to 12+ blade-like “arms”.  The specimens shown are actually the bottoms of the “star” which rested on the sea floor, with the arms upright.  These are colonies.  The bryozoan animal is a filter-feeder that lives in holes in the blades.

These animals were either surface collected, or screened by taking home a bucket of mud and washing it until the specimens could be picked out with a forceps.  Surface collecting was difficult since the reddish mud coated the specimens, making them hard to differentiate from the matrix.  Washing a bucket of mud was much more productive, and every other fossil type could also be found.

These animals look like starfish but are not.  Starfish have not been found in the Fern Glen Formation. 

Last month a friend of mine loaned me his digital microscope to play with and evaluate. One of my Evactinopora specimens never really looked right to me. Using this microscope, I was able to take the following pictures at approximately 250X:

This is not a bryozoan, but a starfish, probably Protopaleoaster sp.  This genus is known from the Ordovician Period (485 – 442 million years ago) but has never been found in the Fern Glen.  That is part of the fun of fossil hunting  --  you can find really cool fossils, and sometimes come up with a species new to science.