324 Iteviews — Br. W. C. Brogger — 



and clay deposits were successively formed at lower levels ; the 

 fauna in these varies in the direction of a gradual increase of boreal 

 and Lusitanian species and the disappearance of Arctic forms. Lists 

 of species found at different localities are given, and the following 

 grouping has been adopted by the author. 



The uppermost, Ostrea-beds, which come next below the level of 

 the Cardium-clay, contain 77 species of mollusoa, of which --^^ are 

 Arctic, i^ boreal, and -fx Lusitanian, indicating a climate nearly 

 similar to the present. In contemporaneous clays at Jarlsberg there 

 are remains of hazel, oak, Eubus, Viola, etc. 



Next younger are the upper Tapes-beds, which are strikingly 

 developed at Drobak to the south of Christiania. The fauna of 

 these beds has been carefully worked out by Sars and others. With 

 few exceptions the species are the same as those in the Ostrea-beds. 

 The commoner genera are Tapes, Ostrea, Mytilus, Astarte, Cardium, 

 and Littorina. Altogether 216 species of mollusca have been 

 recorded from these beds, of which 34 are Arctic, 89 boreal, and 93 

 Lusitanian, or in the proportions respectively of \, -f, -f-. The species 

 indicate a climate notably milder than at the beginning of the post- 

 Glacial period, and probably even milder than the present. Shell 

 beds corresponding to these Tapes-deposits are known in Sweden, 

 along the shores of the Cattegat, in Jutland, also along the Nor- 

 wegian coast, west of the Christiania fjord. At Jeederen, near 

 Stavanger, refuse shell heaps or 'kitchen middens,' of the older 

 Neolithic age, have been found at levels of 18 metres above the sea, 

 showing that the flint folk lived in Norway during the Tapes- 

 period. These beds have also been traced as far north as Vardo, 

 where they contained 26 species of mollusca, of which 3 only are 

 Arctic, 11 boreal, and 12 Lusitanian. A number of these last are 

 now extinct in that region, which confirms the view as to the 

 mildness of the climate in the Tapes-period. 



Contemporaneous with the littoral Tapes-beds, there is in the 

 Christiania valley a widespread clay deposit, probably laid down at 

 depths of 15-40 metres, known as the Isocardia-clay, after its leading 

 fossil, Isocardia cpr, Linn. Eighty-two species of mollusca, mostly 

 the same as those in the Tapes-beds, are recorded from it, together 

 with remains of oak, fir, birch, and hazel. 



Corresponding with the final stages of the post- Glacial elevation, 

 there are a number of littoral shell beds known as the lower Tapes- 

 beds, spread over the Christiania region at levels of 1-13 metres 

 above the sea, and associated with them are clay-deposits, named the 

 Scrobicularia-clays. At Barholmen, near Drobak, these beds have 

 yielded 124 species of mollusca, of which 18 are Ai'ctic, 53 boreal, 

 and 53 Lusitanian ; thus showing an important immigration of 

 southern forms during their deposition. At Brevik numerous 

 species of foraminifera, echinoderms, entomostraca, etc., were 

 determined from the lower Tapes-beds by Miinster, whose list is 

 quoted. 



The Scrobicularia-clays are the lowest and latest post-Glacial shell 

 beds in the Christiania region ; they are now met with at levels 



