The observations will be continued until the author’s acrophobia will reach a 
critical stage. There will then be time to work out the interpretation maps in a 
semi-quantitative manner and to find funds for the publication of the extensive 
photo material. 
REFERENCES 
ZONNEVELD, LS.. 1955 
Natuurreservaten in de Biesbosch en 
het Deltaplan. Natuur en Lands chap 
9: 113-128. 
ZONNEVELD, I.S. 1958 
Bodenbildung und Vegetation in 
Alluvialen Gebiet. 
Symposium für Pflanzensoziologie und 
Bodenkunde. Angewandte Pflanzen 
soziologie 15: 102-117 Stolzenau/Weser. 
ZONNEVELD, I.S. 1959(60) 
De Brabantse Biesbosch. 
A study of soil and vegetation of a fresh 
water tidal delta. 
Bodemkundige studies 4. Neth. Soil 
Survey Inst. 
Volume A, B, and C. 
ZONNEVELD, I.S. 1971 
De Biesbosch is dood, leve de 
Biesbosch. 
(Le Biesbosch est mort, vive le 
Biesbosch). 
Natuur en Landschap, Amsterdam, 
23, 4: 233-250.