1911] PORTLANDIA ARCTICA GRAY 



III. 



As we may learn from my recently published paper, „NogIe 

 bemerkninger om Ra-perioden i Norge", the locality at Kolvik was 

 situated rather far outside the ice-front, when the latter had retired 

 to the Aas-stage, and the ice was accumulating the large mo- 

 raines being left to indicate the work of glaciers during this age. Of 

 course, sedimentation may be expected to have been very slow 

 at the locality in question, as may also have been the state of 

 deposition during the following periods at this remote place in 

 a rather deep sea-bottom. In fact, we are obliged to join, in 

 a complex indicating a rather long lapse of time, a series of 

 fossils all up to the Littorina-niveau l . Some of the mollusca 

 crowding the sea-bottom of the Eidsberg-di vision may of 

 course have survived into the first part of this long and complex 

 period. On the other hand, some of the species, here to be 

 enumerated for the first time, might, indeed, have commenced their 

 invasion during part of the preceding period; at least, we 

 should expect their presence in some more remote places Iying 

 outside the limit of our present investigation. To follow the 

 development of animal life in this place, even after the Port- 

 landia arctica Gray retired or emigrated, we may add the 

 following list of fossils from these subsequent periods, 



Anomia ephippium L. forma typica. This species also 

 occurred in var. cyiindrica, thus indicating also the presence of 

 the vegetation of sea-weeds. 



Anomia aculeata L. 



Anomia patelliformis L. This species occurred rather 

 profusely, and in different varieties. There was even found a 

 specimen measuring 37 mm., very much alike to the variety 

 which I have described on a former occasion 2 , as having an 

 outer appearance very similar to Anomia ephippium, var. 



1 P. A. Øyen: Kvartær-studier i den sydostlige del af vort land, 1908. 

 p. 118. 



2 P. A. Øyen: Det sydlige Norges boreale strandlinje, 1906, p. 8. 



