Supplement to: Halbach, Peter; Gursky, H J; Gursky, M M; Schmidt-Effing, R; Maresch, W V (1992): Composition and formation of fossil manganese nodules in Jurassic to Cretaceous radiolarites from the Nicoya Ophiolite Complex (NW Costa Rica). Mineralium Deposita, 27(2), 153-160, https://doi.org/10.1007/BF00197101