Fossils in Indiana Limestone

Microfossils of the Salem Limestone (aka Indiana Limestone) that existed in the Middle Mississippian Period (340-335 million years ago). Sections of this limestone quarried near Bloomington and Bedford Indiana were used as material for famous buildings around the United States. Buildings such as New York City's Empire State Building & Rockefeller Center and Washington's Pentagon & National Cathedral.  One can learn more about the role of Salem Limestone in the building of the United States in Chapter 6 of the book Stories in Stone: Travels Through Urban Geology by David B. Williams.

This fossil is some sort of bryozoan.  Using its picture it might be a Fenestella or Hemitrypa.

Fossils found in Washington County, Indiana.

 

Thanks to Herb for the Salem Limestone sand material to study.

Endothyra baileyi Foraminifera

Foraminifera fossils from the Salem Limestone of Washington County, Indiana. These creatures are called Endothyra baileyi and existed 360-325 million years ago (Mississippian Period).  Microfossils were studied quite a bit by the oil exploration industry so they could determine the rock layers drills had reached to help find fossil fuels.  I am not sure if they have the same importance today with the proliferation of advanced sensing technology.

Endothyra baileyi foraminifera (Webster's dictionary: "marine protozoans with calcareous shells full of tiny holes through which slender filaments project") described by James Hall in Transactions Albany Institute, volume IV, page 34 published in 1856.  The description is "Shell depressed, orbicular, sub-equally convex above and below, smooth, margin rounded, indented by the septa; spire depressed, involved; last volution slightly oblique, consisting of eight loculi; aperture contracted. The general form of this fossil is depressed, globular, with the involutions deviating slightly from the same plane. Not infrequently, however, the spire ascends in greater or less degree, and one of more loculi become visible beyond the single volution. Sometimes seven loculi only are visible in the volutions. The surface is smooth under the ordinary magnifier, and the outline is indented at the septa."

Listing found in Fauna of the Salem Limestone of Indiana section written by E.R. Cumings, J.W. Beede, E.B. Branson, and Essie A. Smith in the Indiana Department of Geology and Natural Resources Thirtieth Annual Report from 1905 on pages 1201-1202.

Thanks to Herb for the Salem Limestone sand.

Polychaete Annelid Worm

Hundreds of millions of years before the dinosaurs, there existed a ferocious creature. Terror filled victims lay in its path as it rampaged through a Paleozoic sea. Today all that is left is its jaws. Jaws that would rival later carnivores such as the Megalodon shark, Tyrannosaurus rex, and pit bull dogs (Canis familiaris). What beast could generate such carnage and fear? It turns out the polychaete annelid worm from the Ordovician Period. The annelid is a segmented protostome related to modern day leaches and earthworms.

Feast your eyes on such a destructive and potent weapons as these jaws.  Made of a of material so durable it almost appears made yesterday despite being over 400,000,000 years old.  The jaw consists of collagen (protein) fibers and traces of zinc.  Unlike the other fossils I collect that are molds in limestone or shale, or substitutions composed of quartz, calcite, aragonite (brown calcite?), or pyrite this material is apparently original.

Okay, I am exaggerating about this worm.  It appears to have eaten algae, plant leaves, and other worms. These jaws or scolecodonts were found in Ordovician limestone material from Kentucky.  A microscope was used to magnify the fossil at least 60 times its original size.  Very small but fun to find.

Thanks to Herb for the Ordovician gravel they were found in.