Het Eiland Urk: Zijn Bodem, voortbrengselen en bewoners

A scientific survey of a small Dutch island presents detailed geological investigations—borings, trenches, and stratigraphic descriptions—that clarify misconceptions about a supposed rocky core by showing diluvial and alluvial deposits and numerous rolled plutonic boulders; the author documents fresh-water wells that fluctuate with tides, maps elevation and excavation sites, records soil layers and depths, collects mineral and biological specimens, and summarizes local observations on flora, fauna, and human habitation, with methodological notes on tools, sampling, and cooperation with local assistants and a geological commission.