This report presents rare earth element analyses of two sets of samples collected from the Lower Silurian-Upper Ordovician Cason Shale of Independence and Izard Counties in north Arkansas.

It includes:

• Location map of the sample sites
• Table of location coordinates, thicknesses samples, and sample descriptions
• Table of spectrographic data of 1969 samples
• Table of inductively coupled mass spectrometry (ICP-MS) data for 1987 samples
• Table of lanthanide content of average crustal shale, average marine phosphorite, and average Cason phosphorite
• Table of lanthanides in the average crustal shale, average marine phosphorite, average Cason phosphorite, and in samples collected in 1987
• Graph comparing the lanthanide content of the average crustal shale, average marine phosphorite, and average Cason phosphorite sample
• Graph comparing the lanthanide content of some phosphorites to the average Cason phosphorite
• Table comparing lanthanide content and composition in some phosphorites elsewhere in the world and the average Cason phosphorite

*Includes:  13 pages, 3 figures, 6 tables