( 525 ) 



Productus striatns is occasionally met with '), but, like manj- other 

 fossils, it is extremely rare. ') The probability of one of these 

 specimens haxing been transported l(j the Gooi becomes therefore 

 nil. On the other hand, as Staking had already pointed out, they are 

 very eommon at Vise in Belgium, consequently we are justified in 

 concludiug' that the above mentioned fragments must be referred to 

 thai locality. 



Otiier fossil mentioned by Roemkk is the Goniatites sphaericus 

 Mart, (('ilyphioceras spliaericum), a specimen of which had been 

 found near Holten, in Overijsel, and whose original birth-place he 

 claims to have been the valley of the Roer. This fossil, however, 

 is found both at l\atingen and Vise: nothing definite can therefore 

 be saiil with regard to the place of its origin. I may here mention 

 that in lcSi)9, Dr. E. Coi.i.ins brought me a fine specimen, well 

 preserved and but Httle polished, which had been picked up in 

 the gravel of a garden at L'trecht and was very probably brought 

 from the Lek. 



In the railway cutting near Maarn, to the East of Driebergen, I 

 found in 1891^ a block of crinoidal limestone weighing as much 

 as 97 K.G. In that same cutting i-epeatedly were observed pieces 

 of compact black limestone. In 1895, fragments of a very beautiful 

 crinoidal limestone were found in the grounds of the villa Houde- 

 ringe, near De Bilt, at a depth of about 1 M. Other pieces of 

 black and ne.\t to these of grayish compact limestone were found 

 in a railway cutting half way between the stations of De Bilt and 

 Soest. On the whole, therefore, it cannot be said that rocks of this 

 type are largely represented in the diluvial deposits under considera- 

 tion. This is probably owing in a large measure to the sandy nature 

 of the diluvium of those parts which allows the moisture of the 

 atmosphere to penetrate to the limestone and gradually dissolve it. 

 The same physical conditions are probably also responsible for the 

 paucity of erratics of this description in the Provinces of North- 

 Brabant and Lind)urg, antl in the ('ampine. A. Erkns found fragments 

 of crinoidal limestone near Oudenbosch, ') E. Dki.v.vux of carboni- 



1) H. VON Decuen. 1. c. p. 211. 



") C. Daniv. did not even come across a single specimen in the district of Aix- 

 la-Ghapelle. (Der Kohlonkalti in der Umgebung von Aachen. Zeitschr. d. D. geolog. 

 Ges. XLV. Berlhi IWCJ. p. 611). 



') L. G. UE Ko.\im:k. KeclieR-hes sur les animaux ibssiles. V'"^ partie. Mono- 

 graphic des genres Productus et Ghonctes. Liege 1847. p. 30. 



•*) Recherches sur Jes formations diluviemies I. c. p. 07. 



