( 100 ) 



opinion already pronounced with regard to this question in the 

 "Report of the Board of the Dutch Society for the Reclaiming of 

 Heaths to the Provincial Government of Drente about an inquiry 

 into the character of tlie waste land in that Province" ^), where 

 may be read on p. 16 — 17 inter alia: "Red claj especially occurs 

 on the Hondsrug and chiefly in its highest parts." 



On the other hand I do think I am entitled to say that from 

 what is said above appears sufficiently that a distinction betw^een 

 boulder-sand on the ridge itself and boulder-clay only along the 

 sides is in reality wanting. 



Moreover the author has, in my opinion, not satisfactorily proved 

 tliat the boulder-sand of the elevations in South-Drente cannot have 

 been originated by the Avash-out of boulder-clay. He mentions the 

 following reasons for this (p. 98 — 99) : 



1^*. "The hard boulder-clay offers great resistance to eroding 

 agencies. This appears amongst others from its forming steep and 

 more or less projecting parts at the coast as the Roode Klif, the 

 Mirdumer Klif and the Voorst, and e\'en islands, as Ui'k and 

 Wieringen." 



Of course, there is no denying the truth of this statement, though 

 something might be said against it as rega,rds the difference in action 

 between bteral and normal erosive agencies. But moreover may be 

 argued against this that the boulder-clay of the ground-moraine has 

 in a much greater number of places partially or altogether disappeared, 

 no matter how this may have happened. Besides all kinds of 

 intermediate stages between original boulder-clay fas original as we know 

 of, at least) and altogether washed-out bouldei -clay may be observed. 

 In Drente e. g. boulder-clay is nearly eveiy where waslied-out so much, 

 that all limestone has vanished from it. If we consider what impor- 

 tant (juantities of rock have been lost in this way, the powerful influ- 

 ence of such a solution and wash-out cannot be denied. In other 

 places, on the contrary, the limestone is found preserved, but nearly 

 all the finer parts of the clay washed away, so that the boulders 

 lie in more or less chxyish sand (which can also vary in many ways 

 with boulder-clay which has remained more or less intact). I mention 

 these examples to prove that a general appeal to the resistance of 

 boulder-clay to erosive factors in this particular case is of no value. 



1) "Rapport, uilgol»raclit door hel Dagelijksch Bestuur der Nederlandsclie Heide- 

 maatschappij aan de Provinciale Stalen van Drenllie omtrent een onderzoek naar 

 den aard der woeste gronden in die provincie." (Tijdsclir. d. Ned. Heidemaal&cli., 

 Jg. Xll, 1900. 



