Saturday, September 5, 2020

Emmonsia ramosa coral from the Jeffersonville limestone

Among the more common corals that I have found from the Jeffersonville formation near Louisville, KY are these Emmonsia ramosa specimens.  I used the book by Erwin Charles Stumm; "Silurian and Devonian Corals of the Falls of the Ohio". to help ID and found a possible match on pages 67-68, pl 70, fig. 1-3. Here are a number of similar looking specimens.


Most of the specimens I have form finger or column like growths (like the those on the far left and far right of the photo above). Those seem to best fit Stumm's description for Emmonsia ramosa.

"Corallum dendroid, growing in typical staghorn pattern with branches 1-3cm in diameter. Corallites opeing at right angles to surface of branch, polygonal, relatively thick walled, 1-2mm in diameter."

Some of the pieces that look similar have differing growth patterns and corallites sizes so I will need to look at them more closely to see if I have other species.

Here are a few closer views of one of the pieces with better preservation. You can see some of the edges of the corallites have the squamulae (vertical line like growths that helped support the animal) preserved.

These next two pictures are views of natural cross sections through the coral.

I collected these specimens from the Jeffersonville formation (Devonian, Eifelian stage) near Louisville, KY 

References: Stumm, E. C. (1964). Silurian and Devonian corals of the falls of the Ohio. New York: Geological Society of America.

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