( 109 ) 



Staring was however nol ignoranl of the facl thai si ill other 

 factors liave contributed to the formation and the distribution of 

 this sand. 



This may be sure when we see, how on his geological map on 

 some places along (he great rivers alluvial sand-banks are placed on 

 the "zanddiluvium", isolated from the present river-bed and how on 

 the index of the colours "zanddiluvium" and "rivages diluviens" ai'e 

 marked with different character Z and Z' and vet this difference has 

 not been sustained on the map. Here the same colour and the same 

 character Z signifies "zanddiluvium" as well as "diluvial sand-banks" 

 (map I'd' and '-'river banks" map 20). Apparently Staring would 

 not decide, though he was convinced that those formations arc not 

 equivalent, lie may not have said it clearly, yet the honour of 

 having firsl recognized the problem is due to him. 



So Staring's point of view in the matter was as follows: 



The "zanddiluvium" includes all sanddeposits which have been 

 formed after the glacial period and which are not surely alluvial. 

 It has heen washed away by rain water from the gravel-hills in the 

 neighbourhood; yet on many places the possibility of another origin 

 may lie taken into consideration. 



After STARING only three geologists, as far as is learned In the 

 literature I can dispose of, have heen engaged in the study of the 

 postglacial ••zanddiluvium". 



At the 7 th Physical and .Medical Congress in 1899 (Transactions 

 page 450) Dr. II. van ( ' vitki.i.k spoke on "de oorsprong van het 

 heide- of hellingzand". 



In the Staringian "zanddiluvium" formations of a different age 

 must he represented. The orator observed on many places West- 

 Drenthe, Gaasterland, Amersfoort etc.) between tic sand which may 

 he considered with great probability as the product of the washing 

 from the gravel-hills, old surfaces winch he connects with the inter- 

 glacial period by the following reasoning: 



"the younger diluvial currents which have formed the level .sand 

 ot the valleys, have eroded tins "heidezand". The sand of the 

 valleys being formed in the period of the melting away of the first 

 glacier, for the formation of the older "heidezand" only two sub- 

 sections of the diluvial period rest: 1 st . the second glacial period 

 and 2"' 1 . the period of the melting away of the first glacier." 



"The firsl age is possible for the sand which covers the mentioned 

 vegetable beds. So these vegetable beds must he interglacial. The 

 sand which covers the hoiilder-clay directly, may also he a deposit 

 of the first glacier." 



7# 



