In August 2020, I visited The Field Museum of Natural History. It is an amazing place for any one interested in natural history. My main interests were the fossil and mineral collections on display. One specimen that really impressed me was in the Grainger Hall of Gems. It was an opal plesiosaur vertebra fossil from Australia. The Grainger Hall of Gems started off as a Tiffany & Company gem collection exhibited at Chicago's 1893 World's Columbian Exposition. After the exposition was over, it was purchased and made part of the new museum when it opened in 1921.
Over hundreds and thousands of years silica-rich groundwater dissolve fossil remains and leave silica gel. Once the gel hardens it forms opal. Also included in the display are opal fossilized clam and snail fossils.
Recently, I acquired a book entitled Kentucky Fossil Shells A Monograph of the Fossil Shells of the Silurian and Devonian Rocks of Kentucky by Henry Nettelroth 1889. I like to collect the old reference books to see the fossil plates even if I already have a digital copy. The copy I bought was discarded from the Adelbert College of Case Western Reserve University Library in Cleveland Ohio. It does not appear the school teaches paleontology classes anymore so no need for this book.
It just so happened that I got to see an Ordovician Period poriferan (sponge) fossil at the Field Museum of Natural History in Chicago, Illinois, USA last week. The museum display list it as Brachiospongia sp. (490-443 million years old) and found Bridgeport, Kentucky. That same type of fossil is shown in the book. It is described as Brachiospongia digitata (Owen, 1857) on pages 29-30 and image listed in Plate XXXV figure 3 (image below). The fossil was first described by David Dale Owen in First Kentucky Geological Report Volume 2 page 111 as Seyphia digitata. The genus was later named by Marsh in 1867 in American Journal of Science and Arts, 2d series, Volume 44.
Next are two more figures from Plate XXXVI figures 1 and 2.
Dan Phelps the president of the Kentucky Paleontological Society (KPS) gave a talk about these glass sponges to the Dry Dredgers fossil group in Cincinnati, Ohio, USA in 2008. I did not realize how many he had found and the large number of specimens that The Peabody Museum have in their collection.
Also it is brought up that a sponge fossil was found in Tennessee in the 1830s. It turns out that it was documented by Dr. Gerard Troost who I have written about before on this blog in 2009. The Field Museum of Natural History published Annotated Bibliography of Lower Paleozoic Sponges of North America by J. Keith Rigby and Matthew H. Nitecki in Fieldiana: Geology Volume 18, Number 1 on October 25, 1968 which lists references on sponge fossils. Find at this link.
The bibliography reports that Gerard Troost probably described the first fossil sponge from North America in 1838 but did not name it in Description d'un noveau genre de fossiles. Mem. Soc. Geol. France, 3, pt. 1, Mem. 4: pp. 87-96, pis. 9-11.
While visiting Chicago, Illinois, USA, I traveled from Midway Airport to the Roosevelt station via the Orange "L" line. The "L" stands for elevated as in the tracks are high above the street. It is operated by the Chicago Transit Authority (CTA). The address of the station is 1167 South State Street, Chicago, Illinois 60605.
The Roosevelt Station is the closest to the Museum Campus where the Field Museum of Natural History can be found. Because of its locality, tile artwork in one of the passenger walk ways are decorated in a natural history theme.
The first image depicts a trilobite, if I had to guess it is a Silurian Period Calymene. Chicago is built on a 420 million year old Silurian Period seabed so this would be a good choice to show. The border tile in yelllow, black and gray show animals as well. The one on the left appears to show a Permian Period tetrapod Discosauriscus. While the one on the right shows a crinoid calyx with part of its stem.
On the opposite wall is tile shows what I think to be is a brachiopod.
The next image shows a Permian Period Dimetrodon (the fossil of one can be seen at the Field Museum of Natural History in the Evolving Planet exhibit). The smaller tiles from left to right show a straight conical shelled cephalopod, a Silurian Period sea scorpion Eurypterid, and maybe a crinoid column section.
At one end of the walkway is an image representing a human in a form similar to Leonardo da Vinci'sVitruvian Man artwork from 1490. The smaller tiles represent on the left a snail (reminds be of a Turritella or Loxoplocus fossil) and the right a standing bird (reminds me of a Dodo). The human figure seems to represent current time of where our natural world is at.
At the opposite end of the walkway, the tile shows the Big Bang or the beginning of our known natural world.
