I originally had this identified as a ghost shrimp ( Protocallianassa mortoni ).
A special thanks to Carl Mehling from the American Museum of Natural
History for correctly identifying this specimen.

Hoploparia gabbi  page

July 2007

Measuring 2 1/2 inches, this looked like a clump of marl with the tail
sticking out when I found it.

A view of the tail.
Some rather remarkable detail has been preserved. A section of the very back
of the tail or fan is visible.