CHAMPLAIN GLACIAL EPOCH. 6 



the Saxonian epoch of Geikie may be correlated with the Kansan stage of Chamber- 

 lin, and so the European Polandian may have been the equivalent of the Iowa 

 stage. Authors have also correlated the Mecklenburg of Geikie with the Wisconsin 

 of Chamberlin. So far there seems to be agreement, but the remaining epochs are 

 paralleled with great difficulty. I desire to call attention to the Champlain de- 

 posits and ask whether they were not laid down during a period of cold. I will 

 specify a few of their features : 



1. The term Champlain was first applied by me in 1861 to the fossiliferous clays 

 of the Champlain and Saint Lawrence valleys. It included two marine sets of 

 strata, the lowest carrying shells like Leda at considerable depths ; the upper 

 characterized by littoral mollusca, like Saxicava, and certain delta deposits. 



2. The species are such as now live in Arctic regions, as Labrador, none of them 

 coming south of the north part of the gulf of Saint Lawrence. Dawson describes 

 207 species, and my Portland, Maine, catalogue gives 121 species, almost entirely 

 included in the Canadian list. On the Atlantic coast this Labrador fauna has been 

 recognized as far south as Gloucester, Massachusetts, but the influence of what was 

 probably the same climate extended to Nantucket, where the upper Sankaty Head 

 beds contained shells whose summer temperature must have been from 55° to 60° 

 Fahrenheit, fifteen degrees colder than the warmer season of the creatures living 

 in the lower Sankaty Head beds. 



3. The land near New York seems to have been depressed at this time from 50 

 to 75 feet ; in northern Vermont the depression amounted to 400 feet, and to 600 

 feet at Montreal. The deformation amounted to about one and one-fourth feet to 

 the mile. 



4. With such a change of level south-flowing streams would have their sources 

 depressed very much more than their mouths, and hence they would contribute 

 extensive deposits of fluviatile clay, such as are recognized in the middle terraces. 

 Some of these beds carry leaves of Arctic plants, indicating a colder climate than 

 now prevails, and at Hoboken they hold fresh- water diatoms nearly at the sea- 

 level. 



5. Seventy-nine species of maritime plants bordering the great lakes as far as 

 Minnesota, marine shrimps and insects upon lake Superior, and such fish as Tri- 

 glopsis thompsoni in lake Michigan required the presence of ocean water to bring 

 them to their present habitats, so that a submergence of tlie interior of the conti- 

 nent for 700 or 800 feet is called for, and probably the time was that of the deposi- 

 tion of the Champlain clays. 



6. The development of the fluviatile clays often blocked up the courses of the 

 rivers, so that the renewed stream was compelled to change its course and fall over 

 ledges, and this phase of action belonged to the Champlain epoch. Illustration ; 

 of this change of bed are to be found on the Merrimack river at Lawrence and 

 Lowell, Massachusetts, and Manchester, New Hampshire ; on the Connecticut at 

 Holyoke, Turners Falls, Massachusetts, and Bellows Falls, New Hampshire. 



7. With a submergence of probably of from 1,000 to 1,500 feet in the lower Saint 

 Lawrence and an Arctic climate, glaciers would form on three or four mountainous 

 regions, as the Laurentides, Green and White mountains and the Adirondacks, and 

 would discharge bergs in an inter-island area, involving the attendant dispersion of 

 boulders. There would likewise have been a southwest current from the Arctic 

 regions betw^een Labrador and Newfoundland, which carried cooling influences 

 over the whole of the Champlain area and originated till and southwest striae. 



