The solution theory for the origin of stylolites has been further studied in light of the substitute "contraction-pressure" theory recently proposed by B M. Shaub. According to his theory stylolites are a primary structure which originated while sediments were in the unconsolidated state from differential pressure and contraction which compelled "transfer of material by plastic flow." The solution theory holds that stylolites are a secondary phenomenon developed after consolidation and hardening of strata through rock removal by differential chemical solution. The preponderance of field evidence along many lines shows that stylolite-making has involved removal of rock material after lithification of the sediments and that stylolites are, therefore, a secondary phenomenon. Attention is focused upon a recently discovered occurrence of large and well-defined stylolites in sharply laminated limestone which gives no evidence of readjustment or reshaping of sediments through differential squeezing or flow. Field evidence bearing upon the timing of stylolite-making and upon the actual removal of rock at the sites of stylolites is summarized.