A Paleozoic Christmas Greeting

Merry Christmas to all and may Santa bring you lots of nice fossils!

For the curious this image is a composite of four different fossils.  The main tree body is an unidentified Devonian Period horn coral from the Jeffersonville Limestone of Clark County, Indina.  The tree trunk is a unidentified crinoid stem from Lake Cumberland, Kentucky (Mississippian Period, Fort Payne Formation).  The ornaments are Pentremites blastoids from Crawford County, Indiana (Haney Formation(?) and Mississippian Period).  The star is a crinoid stem cross section from the same area the blastoids were found at.  Artistic license was exercised with the fossil colors and illumination.

Blastoid Fossils

The Pentremites blastoid named by Thomas Say in 1825 (maybe in the Journal of Academy of Natural Sciences of Philadelphia, volume 4, p.294). These fossils were found in Crawford County, Indiana (maybe Indiana Springs Formation). The creatures existed in the Mississippian Period.

Dr. Gerard Troost makes note of genus in his unpublished manuscript on crinoids from 1850, "The Genus Pentremites established by our countryman Thomas Say and on which I wrote a memoir (Trans. of the geol. Soc. of Penn. vol. I pag. 224.) is so well known that it requires merely a short notice of how the several species differ from one another; and as to my knowledge, no good figures have been published of the American Pentremites,"  He also talks about Thomas Say's observations in "On The Pentremites Reinwardtii, A New Fossil: With Remarks On The Genus Pentremites (Say) And Its Geognostic Position In The United States Of Tennessee, Alabama, And Kentucky" by Gerard Troost in Transactions of the Geological Society of Pennsylvania, Volume 1, 1835.

Gerard Troost, Thomas Say, and Charles-Alexandre Lesueur were all at New Harmony, Indiana in the 1820s & 1830s. These fossils shown in this entry were not found too far from there to east. It appears they did not document the blastoids found in Indiana since Troost does not mention the state in his paper previously quoted. From the species he attributes to Say in the second paper, those blastoids appear to be found in England, Tennessee, and along the Mississippi River.   Thomas Say is buried at New Harmony.

An interesting paper "The Type of Pentremites Say" by Robert O. Fay in
Journal of Paleontology, Vol. 35, No. 4 (Jul., 1961), pp. 868-873 talks about the holotype specimen of Pentremites godoni found in Kentucky was destroyed in fire (between 1827-1850). It was originally decribed Parkison in 1808 as "Kentucky Asterial Fossil". Professor Samuel Latham Mitchill of University of New York described it as having "a remote resemblance to a small acorn" in 1808 (Uncommon Petrifactions, from Georgia and Kentucky). It goes on using plant terminology so early thinking was it was some sort of vegetation.

 

Archimedes Bryozoan

A series Archimedes bryozoan fossils found in Crawford County, Indiana. These creatures existed in the Mississippian Period. When researching Dr. Gerard Troost, who briefly lived in New Harmony, Indiana (1825-1827), he referred to them as screwstones. His influence was noted by Indiana's first state geologist David Dale Owen (son of New Harmony founder Robert Owen) who recalled that Dr. Troost taught him that coal would not be found in layers of rock where screwstones were found.

Interesting, the name Archimedes for this fossil came from the writings of David Dale Owen who credited the name's origin to Charles-Alexandre Lesueur (French naturalist-artist) who was at New Harmony with Robert Owen, William Maclure, Thomas Say and Gerard Troost.

If you visit New Harmony, look at the weather vane on top of one of the original laboratory buildings. It has a blastoid and Archimedes bryozoan on it.

 

 

I read something in a scientific journal where two researchers were speculating that the Archimedes and Fenestella bryozoans might be two separate entities instead of one as shown on these next two images.  It looks to me that the bryozoan netting had attachment places on the threads of the screw shape.  So it would look like it was all part of one creature.  It is possible I read something wrong as well.