A technique used for measuring the pH (acidity/alkalinity) - hydrogen ion concentration of a soil or sediment. The results of the test may suggest what type of remains are to be expected on a site. In an acid soil, bone, shell, and carbonate lithic debris will not survive, but pollen grains will; in an alkaline soil, there will be only rare occurrences of pollen, but calcareous material should be more plentiful. The pH is tested by moistening a sample of soil with neutral distilled water and dipping indicator paper into it. The resulting color, which depends on the pH content, can be matched against prepared charts of known pH values.