CENOZOIC TIME — QUATERNARY. 995 



W. Upham mentions (1891) the occurrence of similar warm- water sliells in the vicinity 

 of Boston. W. F. Ganong reports (1890) that similar shells have been found in Halifax 

 Harbor, Minas Basin, St. Mary's Bay, and on other parts of the Acadian coast. 



Tliese species are relics of a past southern population ; none of the shells are found in 

 elevated beaches ; and hence the migration from south of Cape Cod took place in the 

 Recent period. Such a migration, extending to the St. Lawrence Gulf, was not possible, 

 unless the Labrador current had first been turned aside ; and a closing of the Straits of 

 Belle Isle would liave brought this about. This implies an elevation of about 200 feet ; 

 and it may be that the rise which introduced the Recent period carried the continent, 

 to the north, to this lieight above the present level. In the Champlain period of sub- 

 sidence the Straits were open, this being proved by the cold-water shells of the now 

 elevated beaches. 



FOREIGN. 



Whatever the facts relative to interglacial epochs in Europe, it appears 

 to be certain that after a long period of glaciation there was a time of widely 

 extended subsidence, initiating a period of ameliorated climate ; and that 

 this period was similar to that of the Champlain period, not only in this 

 initiating subsidence, but also in marine deposits and other phenomena. 

 This period of subsidence in Europe had, like that of America, its sea-border 

 formations in Sweden and Norway closely like those of the coasts of Maine 

 and the St. Lawrence, even to the " Leda days " and " Saxicava sands," and 

 its extensive fluvial formations along the river valleys. According to J. Geikie, 

 the submergence of Great Britain after the epoch of maximum glaciation was 

 probably 500 feet. This author inserts, as has been stated, a return of 

 glacial conditions, and then another interglacial before the Glacial epoch 

 generally recognized as the second ; and estimates the subsidence of Scotland 

 during this second interval as 100 feet. A 100-foot terrace forms a wide 

 plateau in the estuary of the Forth. The depression ten miles east of Glas- 

 gow was at least 524 feet, as indicated by the presence of marine shells in 

 beds of clay, which are overlaid as well as underlaid by beds of till. The 

 marine shells present are those mainly of Arctic seas, like the St. Lawrence 

 species. Among them are Saxicava rugosa, Pecten Islandicus, Natica dausa, 

 Trophon dathratum, Yoldia arctica, Macoma sabulosa. 



Northern Germany was submerged during interglacial time. In Sweden 

 the depression exceeded in some parts 600 feet. Near Uddevalla, in southern 

 Sweden, at levels of 200 to 400 feet, shells of Mya truncata, Saxicava rugosa, 

 Astarte horealis, Natica dausa, Buccimim Groenlandicum, etc., are in great 

 abundance ; and show thereby that the subsidence was of long continuance. 

 Erdmann concludes that, at this time, the Baltic was connected with the North 

 Sea, over the region of lakes from Stockholm westward, and with the Arctic 

 Ocean by a great channel leading northeastward over Finland to the White 

 Sea. The Caspian and Aral were united and connected with the Arctic Ocean, 

 and so continued to the close of the Champlain period. As in America, the 

 period was the time of flooded rivers and lakes, and of the most extensive 

 freshwater formations in the world's history. Dupont states that with the 



