26 P. A. øyen [No. 12 



but even leading ones, such as are enumerated in page 4 of 

 the present paper. 



Immediately covering the ice-scratched rock beneath, a sheet 

 of ground-moraine is in most cases to be met with and this 

 sheet of ground moraine is in its turn as a rule covered with 

 different deposits of a fluvio-glacial origin. Moreover, in many 

 cases the peripheric facies of these last mentioned deposits prove 

 to be a fossil-bearing clay of glacio-marine character. And, the 

 fossils of this clay are true arctic ones, for instance, Portlandia 

 arctica, that may in the peripheric deposits be traced from below 

 the present sea-level up to at least one hundred and ten metres 

 above sea occurring, as we have seen, as well outside the large 

 ra-moraine as inside or upon that moraine ridge itself. On com- 

 paring the faunistic lists, however, we can not avoid to notice some 

 difference in the faunistic elements or series of fossils of the two 

 above mentioned clay-deposits that are separated by the ra-moraine. 

 The clay-deposits of the ra-stage or the preceding one are as a 

 rule more rich in certain gastropoda especially of the Buccinum- 

 and Sipho-groups. When we enter upon the deposits of the 

 Horten-division of the Søreng intraglacial stage (P. A. Øyen: 'A 

 brief Summary of the Evidence furnished by Glacial Phenomena 

 and fossiliferous Deposits in Norway as to Late-Quaternary 

 Climate' in 'Postglaziale Klimaveranderungen', Stockholm 1910), 

 we do not, however, find that Portlandia arctica has disappeared 

 but she now lives in company with some new species, that must 

 at least be rather rare, if at all present, in the next preceding 

 layers, as they have not as yet been found in the deposits of the 

 Ra-stage or the next preceding one. Among these species we 

 may especially mention the appearance of Portlandia intermedia 

 and Yoldia hyperborea, the latter one being especially interesting 

 as we have been able to trace it trough the sections of Braarud- 

 aas (Horten), of the tile-work of Rakkestad, and of the railway- 

 station of Spydeberg or, in other words, through the whole series 

 of layers belonging to the Søreng intraglacial stage and even in 

 part to the Aas-stage itself. On the other hand, Portlandia 

 arctica itself has not as yet been found in the latter or Eids- 



