Vol. 52.] 



PLIOCENE DEPOSITS OE HOLLAND. 



765 



exception the species in this list occur in the Scaldisien or Walton 

 C. Prom beds regarded as Amstelien. 



Crag. 



Anomia ephippium, Linn. 

 Pecten opercularis, Linn. 



„ ventilabrum, Goldf. 

 Mytilus edidis, Linn. 

 Nueula Cobboldice, Sow. 



,, lavigata, Sow. 

 Leda lanceolata, Sow. 



,, my alls, Wood 

 Cardium edule, Linn. 



„ subturgidum, d'Orb. 



„ grcenlandicum, Chem. 

 Lucina divaricata, Linn. 

 Cyprina islandica, Linn. 

 Venus ovata, Penn. 



Donax vittatus, Da Costa 

 Tellina obliqua, Sow. 



„ pr (Biennis, Leathes 

 Semele alba, Wood 

 Mactra solida, Linn. 



„ deaurata, Turt. 



„ subtruncata, Mont. 

 Mya arenaria, Linn. 

 „ truncata, Linn. 

 „ Binghami, Turt. 

 Corbida gibba, Olivi 

 Turritetta terebra, Linn. 

 Littorina littorea, Linn. 

 Eingicula ventricosa, Sow. 



These are, with one or two exceptions, among the most abundant 

 -and characteristic species of the upper horizons of the English Crag. 

 In addition to the above, the following have been found in the 

 Amstelien, though not abundantly : — Leda minuta, Natica clausa, 

 and Fusus scalariformis, Arctic shells, and Scrobicularia jpiperata, an 

 Upper Crag form. 



The fossils named in Table A are evidently Diestien, while 

 Table B contains the same kind of admixture of Coralline and 

 Red Crag forms that is characteristic of the Walton bed, which it 

 resembles generally more nearly than any other horizon of the 

 ■Crag. 



The difference between Tables B and C is very marked. The 

 first contains four characteristic southern shells, and one exclusively 

 northern (found also at Walton); the other, one southern (an Upper 

 Crag species), and four northern forms, two of the latter being Arctic. 

 The fauna of Table C presents a more recent facies, resembling 

 that of the Butley Crag, not merely in the presence of boreal shells, 

 but in the absence of many characteristic Walton species. No one 

 familiar with the English Crag would regard this list of mollusca 

 (Table C) as representative of the Walton zone. 



The following analysis of all the species of mollusca found at 

 Walton, in the Scaldisien and Poederlien of Belgium, and in the 

 Amstelien of Holland will show, on the one hand, the close resem- 

 blance of the three first, and on the other, the great difference 

 between these beds and the latter. 



Walton 1 



Scaldisien 



Not known 

 living. 



36 % 



37% 



Cor. Crag 

 or Diestien. 



71% 

 75% 

 73% 



63 / 



Southern. 



19% 



21% 

 17% 



Northern. 

 5-5% 

 2-8 % 



Poederlien 



42% 

 30 % 



4-6 % 



Amstelien 



6-8 % 



13-7 % 



1 From information kindly supplied to me by Mr. Kendall. The Walton 

 analysis is taken from the fauna of both the upper and the lower beds. 



3f2 



