QUATERNARY DEPOSITS OF BRITISH ISLES BROOKS. 305 



We have next to compare the sequence in Denmark and Sweden 

 with that worked out by C. Brogger in the Christiania region, 200 

 miles farther north (58). This sequence and the variations of 

 level of the land are as follows : 



The older Yoldia clay is a reconstructed bowlder clay with 25 

 species of high arctic Mollusca formed immediately behind the re- 

 tiring glacier, indicating a land level about 30 meters lower than 

 the present. The land then sank another 45 meters, while the cli- 

 mate ameliorated, so that one finds the larger form of the high arc- 

 tic Portlandia arctica Gray of the older Yoldia clay represented by 

 smaller forms of the same mussel in the younger Yoldia clay. At 

 this time the climate was similar to that of the west coast of Spitz- 

 bergen. Immediately above the younger Yoldia clay is a clay de- 

 posit with a more arctic deep-water fauna, chiefly Area glaeialis 

 Gray represented by a large form. This older Area clay repre- 

 sents a submergence of about 100 meters and is only found outside 

 the great Ra moraine or in immediate connection with it, whereas 

 the following middle Area clay, with a smaller form of Area gla- 

 cidlU, representing a slight amelioration of climate and a still 

 greater submergence, occurs also inside the Ea moraine. The latter, 

 therefore, which represents a prolonged still stand of the ice with 

 possibly a slight readvance, evidently corresponds to the older Area 

 clay. 



The continuation of the late glacial sequence in the Christiania 

 region is described by Brogger as follows : 



The middle Area clay, indicating a submergence up to 150 meters, 

 is followed in continuous series by the younger Area clay with a 

 still smaller form of Area glacialis and many boreo-arctic Mollusca. 

 The occurrence of this fauna in connection with a corresponding 

 shore fauna, which occurs in the Portlandia clay with Portlandia 

 Icnticulata and in connection with the series of moraines in the 

 Christiania Vallej 7 , indicates in this region a submergence of the 

 land to about 200 meters. The progressive sinking still continued, 

 as shown by the marine shores of the neighborhood of Christiania, 

 where terraces of accumulation with a boreo-arctic fauna and corre- 

 sponding erosion phenomena indicate the shore at a height of 21G 

 meters above sea level. Corresponding to this sinking of the land 

 there occurs at many places on the present shore line a fossil 

 Lophelia fauna, and this period coincided with the epiglacial 

 period, during which the great moraines were covered by the south- 

 ern end of great inland lakes. After this the land began to rise and 

 the climate ameliorated steadily. The upper, middle, and lower 

 My a banks, at 200 to 100 meters, corresponding to the older Cardium, 

 clay, are followed by the younger Cardium clay, 100 to 80 meters, the 



