This report presents the results of the analysis of 728 lithic samples for mercury content. The samples were collected in 1994 from formations in the Ouachita Mountain region after a study of the source of mercury in fish in the Ouachita River basin indicated that the mercury did not originate from a point source.

The report includes:

• Discussion of sampling procedures and statistical discussion of the analytical results
• A foldout location map of the sample sites
• A foldout map depicting mercury concentration in the bedrock of the Ouachita Mountains of Arkansas
• Figures showing the distribution of mercury concentration in the samples and log distribution of mercury sample concentrations
• A table showing the distribution and range of concentration of mercury by formation, by geologic age, by principle lithology, and by organic and carbon content
• A tabulation of Ouachita Mountain rock samples listing: sample number, mercury concentration, stratigraphic unit, and lithology of the sample

*Includes: 25 pages, 4 figures, 1 table