1913] SOME CLAY DEPOSITS IN THE S.-E. PART OF NORWAY 21 



In this fossil-bearing, rather fine and bluish-grey clay some- 

 times small clay concretions are also met with. While the clay 

 itself is sometimes of a streaked or wavy-lined colour we 

 always find these concretions to be of a bluish-grey one and to 

 be in some cases fossil-bearing too more especially carrying 

 Portlandia lenticula. Only in some scattered places a reaction 

 of HG1 may be slightly observed. 



The above list of fossils clearly shows that there is a 

 very close connection between the deposit at Braarudaas 

 near Horten and this lower portion of the deposit at the tile- 

 work of Rakkestad. These deposits, both of them, belong to the 

 Søreng-period. The first one more specially belongs to the 

 former part of that period while, on the other hand, the latter 

 one represents a later part of the same period as, no doubt, the 

 first part of the Søreng-period is represented in layer A of the 

 Rakkestad section. 



As already above mentioned, however, casts of Portlandia 

 lenticula were not uncommon even in division F of this section, 

 especially in the lower part of it. The casts here often occurred 

 in such a manner as to prove that the animals themselves had 

 lived in clustered colonies quite in the same manner as also those 

 described by me on a former occasion (P. A. Øyen : Kvartær-studier i 

 den sydøstlige del av vort land, 1908, pp. 26, 27) from the section 

 of Lekum. I think a correlation of the strata in question highly 

 probable. In addition to the rather numerous specimens of 

 Portlandia lenticula in the lower part of this division of the 

 Rakkestad section a very fine but unfortunately broken east 

 specimen was found which on directly performed comparison must 

 be referred to Axinopsis orbiculdta G. 0. Sårs, of Iength 3 mm. 

 Interesting as is this find from a more biological point of 

 view the stratigraphical importance may be still greater as it 

 admits a correlation with some strata that I have recently dis- 

 covered within the town of Christiania itself (P. A. Øyen: The 

 Quaternary Section of Foss, 1913, pp. 5, 6). 



We might be justified in regarding the layer A of the 

 Rakkestad section as contemporaneous with the Horten-division 



