Preface

Hundreds of boreholes were made in the southwestern part of The Netherlands during the last century. Many of these were for the exploration of oil and gas and passed through Holocene and Pleistocene strata without detailed attention being paid to these superficial deposits. Others were made to obtain drinking water, had a purely scientific purpose, or were made in relation to water defense works. A well-known, and also one of the oldest boreholes on the island of Voorne-Putten, is the one made in the centre of the city of Brielle in 1903, in search for drinking-water. That borehole was as deep as 90 m. It was described and investigated by the geologist Lori. Another well-known borehole, also located in Brielle, yielded important data for the tuning of Early Pleistocene chronostratigraphy and mammal-biozonation. In this volume frequent references are made to these boreholes.