Alispirifer imbricatus brachiopod

This brachiopod seems to match one shown on the Indiana State Museum collection database website that is identified as Cf. Alispirifer imbricatus nomen nudem.  Just to clarify some details of this name as I rarely use some of these terms on the blog, Cf. is the abbreviation of the Latin "confer".  My interpretation of this is the fossil is like another fossil but the identification is not sure.  "Nomen nudem" is Latin for "naked name" which in this context means the scientific name is not official because it was not published or incorrectly published.

My cousin gave me this specimen found on a recent hike in Indiana.  It was found in Washington County, Indiana from the Mississippian Period and probably from the Borden Group (Spickert Knob Formation).  The fossil appears to be an internal cast.  The rock it consists of is hard, he had another fossil I was trying remove a nodule from with the engraver.  With the engraver set at its highest level the rock would not break off.

Learn more about Indiana's past by visiting the Indiana State Museum Center for Science and Culture.  While there: Celebrate. Investigate. Remember. Learn.

Heliophyllum of the North Vernon Limestone

Heliophyllum sp. horn coral found in the Beechwood Member of the North Vernon Limestone of Clark County, Indiana.  This coral existed in the Devonian Period.

Schlotheimophyllum or Ptychophyllum Horn Coral

These Middle Silurian Period (428-423 mya) horn corals are from the Louisville Limestone of Jefferson County, Kentucky.  They appear to be Schlotheimophyllum (referred to by William Davis as Ptychophyllum).  Usinig Erwin Stumm's book Silurian and Devonian Corals of the Falls of the Ohio, these horn corals might be Schlotheimophyllum fulcratum (aka by Davis as Ptychophyllum stokesi) or Schlotheimophyllum ipomaea.  Another author Herzer in 1902 referred the genus as Chonophyllum.

Stumm refers to these as scattered hollow spines (p.25) when describing the Schlotheimophyllum fulcratum but I believe they are some sort of holdfast or anchor device used by the coral to connect itself to the sea floor/object or another horn coral.

These last three images are of plates from Davis's monograph that have been photo enhanced and labeled.  These horn coral specimens were labeled Ptychophyllum stokesi of the Upper Niagara Limestone [now called Louisville Limestone].  Images from book: Kentucky Fossil Corals - A Monograph of the Fossils Corals of the Silurian and Devonian Rocks of Kentucky by William J. Davis, Kentucky Geological Survey 1887. Thanks to Kentucky Geological Survey website of Plate 105.