QUATERNARY AGE. — CHAMPLAIN PERIOD. 559 



up by gravel and sand from the unlading glacier. . It has been shown 

 that the Rhine owes its present channel at the Falls at Schaffhausen 

 to its having been forced out of an older one ; and it is probable that 

 the Chainplain period was the time of the catastrophe. 



The depression ten miles east of Glasgow 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 Arctica, Pecten Islandicus, Natica clausa, 

 Trophon clathratum, Yoldia glacialis, Macoma sabulosa. In some parts of Wales, 

 Ireland, and the northern half of England, it appears to have been 1.000 to 1,400 feet, 

 stratified Drift with marine northern shells occurring at this height on the south side 

 of the Menai straits; also at a height of 1,300 feet, on Moel Tryfaen; 1,200 feet, at 

 Macclesfield in Central England; 1,000 to 1,200 feet, in Ireland, County Wexford, 

 south of Dublin; at a height of 568 feet, near Blackpool in Lancashire, fifty miles from 

 the sea. In the depression separating Wales and England — Murchison's "Severn 

 Straits " — beds of marine shells are found at a height of 100 feet. 



The lake and river terraces in Great Britain, and especially its northern port, Scot- 

 land, are on a scale as grand as the sea-shore deposits. The "'benches" of Glen Roy 

 are an example of them. The upper terrace is 1,139 feet above tide-level; the 

 second, 1,059 feet; the third, 847 feet. This is one among many cases that might be 

 cited. As a general thing, the elevated sea-border formations occur on the coasts of 

 regions whose interior is diversified with high lake and river terraces. 



A deposit generally regarded as among the earlier Quaternary of Britain, or transi- 

 tional between the Pliocene and Quaternary, is called the "Cromer Forest Bed"; it is 

 traced for over forty miles along the Norfolk Cliffs, between Cromer and Kessingland, 

 beneath Drift. It contains remains of plants, insects, and shells of living species, along 

 with the remains of some Pliocene as well as many extinct Quaternary species, and 

 some modern Mammals (p. 571). 



The sea-border shell-bearing deposits of southern Sweden have a maximum height 

 of 200 feet; of western, 200 to 500 feet, and mostly 325 to 400 feet (Erdmann); those 

 of the northwest coast of Norway, in Hardanger, 293 to 331 feet (Sexe). 



The valley of the Rhine and those of its tributaries contain extensive deposits of this 

 Chainplain era. The material of the alluvium is mostly the loess, a fine yellowish-gray 

 loam, much of it unstratitied, — generally a little calcareous from pulverized shells; and 

 in some parts it contains glacially-marked stones. It rests in some places on stratified 

 gravel or sand. Between Basle and Binnen, this alluvium near Basle has a height of 

 660 feet above the river; and through much of it there are land and fresh-water shells. 

 The loess may be in part a deposition from the floods consequent on a second glacial 

 epoch, mentioned beyond (p. 561). Similar facts are reported from most of the river 

 valleys of Europe. The deposits on the Danube are as extensive as those of the Rhine; 

 and Professor Suess states that stones occur in it that were probably dropped by float- 

 ing ice. 



In Belgium, according to Dupont, along the valley of the Lesse, and others, the lime- 

 stone caverns situated at the greatest elevations — eighty to one hundred feet above the 

 present river — are those which contain the older remains of Mammals; and those be- 

 low are successively more recent as their height is less. Moreover, the river alluvium 

 shows that, when the upper caves were inhabited, the valley was filled with water and 

 river-border deposits, nearly to the level of the cave. Thus the change of level, which 

 marked the close of the Champlain period and the introduction of the Recent period, is 

 very strikingly exhibited. 



