Soil opal phytolith content is intimately related to internal soil drainage; highest opal contents occur in the middle of the drainage sequence. Soil productivity is invoked to explain the catenary opal distribution. Phytoliths are concentrated in the surface horizon of Planosols but distributed downward to 20 inches in Brunizem and Gray‐Brown Podzolic soils. Differences in chemical and catenary milieu, soil fauna, or loess depositional pattern are possible causes for depth distribution differences.