The biomass, numbers of individuals and mineral content of the arthropod fauna in the litter of a mixed hardwood forest were examined. The biomass values of the litter arthropods were generally higher than in other forests. Possible reasons for higher biomass values are discussed. Potassium and calcium standing crops are compared to those of a Liriodendron forest in Tennessee. With few exceptions the potassium values are comparable. However, there appear to be great differences in the calcium values. INTRODUCTION The forest constitutes an ecosystem in which organic and inorganic elements interact. The basic mineral nutrition of forest vegetation is provided by rock weathering and mineral-laden rain. The forest is charged and recharged by organic products from the vegetation (Spurr, 1964). The nutrient recharging is accomplished to a great extent by litter decomposition which releases the nutrients bound up in the dead plant structural material. Decomposition is accomplished by the activities of both the forest floor microflora and fauna. As organic materials reach the forest floor, they are attacked by the microflora and fauna, releasing nutrient substances, and 40 to 90% of the initial weight may be lost during the 1st year, the actual amount varying with species and locality (Edwards et al., 1970). Witkampl and Olson (1963) showed a nonlinear rate of weight loss by leaf litter during the 1st year, often with an initial rapid loss of weight, possibly due to leaching of soluble materials. This is followed by a slower loss rate during the winter months and subsequent acceleration during spring and summer (Crossley, 1970). Fresh leaf litter may remain unpalatable to soil fauna until the polyphenols in the stem and leaf material are removed (Edwards and Heath, 1963; Satchell and Lowe, 1966), and this may delay faunal attack on the litter for some time. Several studies on the dynamics of litter breakdown by fauna have been reported. Satchell (1967) suggested there may be extensive incorporation of litter into the mineral soils by the feeding of earthworms. 'Research supported in part by the Eastern Deciduous Forest Biome, US/IBP, funded by the National Science Foundation under Interagency Agreement AF-199, 40-193-69, with the U.S. Atomic Energy Commission Oak Ridge National Laboratory, and in part by U.S. Atomic Energy Commission Contract AT-(38-1)-641 with the University of Georgia (D. A. Crossley, Jr.). Contribution No. 147 from the Eastern Deciduous Forest Biome, US/IBP. 2 Present address: Ecology Center, Utah State University, Logan, Utah.