Thursday, January 14, 2010

Quest for a Horn Coral

I continue to search for the elusive Bordenia knappi (Hall, 1882) horn coral.  It is challenging to understand some of the paleontology literature though.

From the library, I checked out Treatise on Invertebrate Paleontology Editor Curt Teichert, Part F Coelenterata Supplement 1 Rugosa and Tabulata by Dorothy Hill Volume 1, The Geological Society of America, Inc. and The University of Kansas 1981.  Page F147 it says, "Bordenia Greene, 1901, p. 57 [*B.zaphrentiformis] Solitary, irregular ceratoid or trochoid with talon, or weak colonial, with peripheral offsets; major septa long but amplexoid; minor septa short; tabulae complete, horizontal, with downturned edges; no dissepiments."  It then lists it as Mississippian Period found in Indiana and Kentucky.  Whoa!  I think this is a Devonian Period coral.

George K. Greene published Contributions to Indiana Paleontology on page 99 describes Bordenia knappi and with plates 31 figures 4-11.  "Zaphrentis deformis, Hall Twelfth Annual Report of the Indiana Geological Survey, 1882, page 290, plate 20, figure 9-10.
Zaphrentis Knappi, Hall, Thirty-fifth Annual Report of the State of New York, page 438, 1884.
As the descriptions for both species are the same, I prefer the specific name Knappi, as this was intended as a compliment by Prof. Hall, to his old friend, Dr. James Knapp, of Louisville, Ky.
Corallum simple, or composite, and sometime growing socially, two or more together, with a broad scar at the point of attachment.  Gradually, or sometimes more rapidly, expanding in diameter to the calix.  Height varying in different individuals, from fifteen to forty millimeters.  Diameter of calix, from ten to twenty-five millimeters.  Depth, five to ten millimeters, with a smooth space in the center of the calix, occupied by the tabulae, from ten to twelve millimeters in diameter.  Number of lamellae, from thirty to thirty-two, in the circumference of a calix, twenty-five millimeters in diameter.  When well preserved they are unequal in size, and sharp at the margin, gradually descends to to the smooth space in the center of the calix, but does not extend on the side of the coral.  Exterior with numerous strong rounded annulations and wrinkles, caused by periodical growth.
Found in the Upper Devonian (Hamilton group) at Charlestown, and in the strippings above the different cement quarries, throughout Clark County, Indiana, now in my collection."

E.C. Stumm's book Corals of the Silurian and Devonian Corals of the Falls of the Ohio describes it on page 46 as "Corallum simple, small, highly distorted, with thick epitheca and one or several talons of attachment.  Average length about 3 cm, average calyx diameter 1.5 cm.  Calyx very shallow.  Septa about 25-30, of equal size, extending more than half distance to axis.  No distinct fosula. Tabulae complete, about 2 mm apart.  No dissepiments."