In 1866 two prize essays were published by the Dutch Society of Sciences, onewritten by C.E.Weiss, the other by L. Dressel, both dealing with the origin of rocks. Two jury-reports are given, which reflect the state of the controversy neptunism-plutonism in the Netherlands in the third quarter of the 19th century, the first by J.G.S. van Breda (1788-1867), the second by W.C.H. Staring (1808-1877).