The refined dating technique based on both pollen density and radio-carbon dating proposed by Middeldorp (1982) was applied to five curves of a pollen- and macro-remain diagram from a peat section from the Engbertsdijksveen (Vriezeveen, The Netherlands), Percentages curves of Alnus, Quercus, Corylus, alkaline soluble humic acids and coarse fraction of peat were then subjected to time series analysis by means of Periodic Regression (Briskin et al. 1980). In this way periodicities of approximately 1450, 1000, 800, 600, 500, 350, 200, 145, 85, 40 and possible 22 years could be established with reasonable confidence. Several of these periods seem to correspond to known sunspot cycles (22,40,80,150,200 and possibly 1000 years).