For the compilation of the map of fossil localities I have followed the example of Dr. A. Tobler (bibl. 194), arranging the localities according to age. The localities from which more than one formation has been recorded, are numbered for the oldest formation found. In the list these numbers are repeated in brackets under the heading of the other younger formations that have also been found. Thus brackets around a number are an indication that older sediments are known from the same locality. In those fossil localities are included that occur on Dutch territory and from which a collection of the fossils has been described. Vague indications in preliminary reports have not been taken into account.