Yadkin Pit, Virginia, USA 36.76 N, 76.38 E Yorktown Formation, Pliocene
The four tests have been provided by USGS Reston and are described in Harry J. Dowsett, Linda B. Wiggs: Planktonic foraminiferal assemblage of the Yorktown Formation, Virginia, USA
in Micropaleontology; April 1992; v. 38; no. 1; p. 75-86