QUATERNARY DEPOSITS OF BRITISH ISLES BROOKS. 307 



submerged, except possibly for a small area in the northwest, where 

 Litorln-a deposits occur below sea level (61). No cold period subse- 

 quent to the ice melting has yet been proved in the peat bogs, so that 

 the Scanian end moraine at least is unrepresented. 



Nordmann (62) applies the term "older Yoldla clay" to the two 

 beds with Yoldia {Portlandia) arctlca^ and the term "younger Yoldia 

 clay" to the bed with Portlandia lenticulata^ and considers that the 

 latter, with the associated epiglacial moraines, represents the Z^r- 

 'pJiaea sands of Denmark, while the At^ca clays represent the Allerod 

 oscillation. This, however, is not borne out by the climatic values 

 of the various species of Mollusca, and it further leaves the great Ra- 

 moraine quite unaccounted for. The epiglacial moraine appears to 

 represent a later cold period of considerably less intensity. 



In the Bergen region the conditions were described by C. F. Kolde- 

 rup (63) as follows. The highest well-marked shore line lies in the 

 west at 50 to 60 meters and in the cast (inner fjords) at 60 to 70 

 meters. These terraces contain Yoldia arctica^ and are termed by 

 Kolderup the " Yoldia " or " epiglacial terraces." They do not mark 

 absolutely the highest level of the sea, for here and there a small 

 terrace is found a few meters above, but indicating only a very short 

 stay at this level. As the inland ice melted, the ice divided into local 

 glaciers, whose ends reached the sea. A still stand or slight readvance 

 at this stage is marked by a few important end moraines, which cor- 

 respond to the Ra-moraines of the Christiania region. Arctic mol- 

 lusca, indicating a climate colder than that of the extreme north of 

 Norway, occur in beds mixed up with these moraines, but the Yoldia 

 terraces, with a fauna like the present one of the "VVliite Sea, belong 

 to the end of the Ea-moraine period. Conditions were thus essen- 

 tially similar to those of the Christiania region. 



Ki Christiansand and Trondhjem, J. Rekstad found that glacial 

 conditions continued until the maximum subsidence (76 to 134 

 meters) was reached, after which it ameliorated, and present condi- 

 tions {Tapes period) obtained when two-thirds of the ensuing eleva- 

 tion had taken place. 



Still farther north conditions have been studied by O. T. Gronlie 

 (64) in the neighborhood of Tromso, about latitude 69 north. Ho 

 found that during the late glacial subsidence the climate continued 

 arctic, but when elevation commenced conditions became milder, ulti- 

 mately milder than the present. Renewed subsidence in the " Tapes 

 period " was associated with a deterioration of climate, but at the 

 new minimum land level the climate again became milder. This 

 subsidence was probably the equivalent of the Litorina subsidence, 

 Avhich, as will appear later, was very widespread over the northern- 

 most part of the North Atlantic and the Arctic Oceans. 



