Geochemical Studies is a collection of papers dealing with ore petrology, particularly on the genesis of ores found in sediments. One paper describes the minor elements in metal deposits in sedimentary rocks, focusing on geochemical work on certain classes of ores in sediments and on the theories of origin of the deposits. With better techniques of microprobe analysis of trace elements, the paper notes that ore deposits in sedimentary rocks can be characterized by their minor element suites. One paper points out that large ore deposits cannot possibly be formed by a migration of substances (known as "negative" diffusion). The paper estimates that the quantities of material that can be accumulated in a sediment horizon with a great affinity for these materials, say in a period of one billion years, will still not be sufficient to produce a large ore deposit. The paper estimates the necessary diffusion coefficients that occur in deep structures, where increased mobilities of various substances occur. Geologists, geochemists, and engineers working with fossil fuels will find the collection highly significant.