652 REPORT— 1897. 



certain mammals of that time over North and South America, as shown hy some 

 of Professor Cope's last worii, and by the occurrence of eliptics in Guadeloupe. 



If the physical phenomena be correctly interpreted, the changes of levels of 

 land and sea, and the dependent variations of currents, &c., seem to be sufficient 

 cause for the Glacial period, as advocated by Lyell and many others, while the 

 writer has only pointed out where changes have occurred. 



Since the epoch of great elevation there have been extensive subsidences iu 

 America, so that much of the region, where not actually submerged, stood near 

 sea level. The subsequent elevation has been unequal and most pronounced in the 

 mountain regions, as of New England, New York, &c., where tilted beaches, 

 deltas, and terraces occur on all sides of the high mountains in such locations as 

 would require the base levels of erosion to be reduced to near sea level, while the 

 subsequent rise of the land has lifted them to a height of at least 2,700 feet. 



Between the phenomena of great elevation and depression there are many 

 others not yet assigned to their proper places, which possibly accounts for 

 various explanations of the surface features. 



8. The Champlain Submergence and Uplift, and their Relations to the 

 Great Lakes and Niagara Falls. By Frank Bursley Taylor, of 

 Fort Wayne, Indiana. 



There is much evidence that the disappearance of the Champlain submergence 

 was a recent event in geological time. The skeletons of whales and seals found 

 within the submerged ai'ea are not petrefactions, but bones ; its marine shells are 

 fresh in appearance. Many of the species iound live now in the Gulf of the 

 St. Lawrence. The river channels traversing the old sea bottom betray their 

 youth by many signs. Its soil shows less oxidation than that of the adjoining 

 unsubmerged drift area. 



A remarkable abandoned beach surrounds a large portion of the upper Great 

 Lakes. It leads to a low col at the east end of Lake Nipissing, and is hence 

 called the Nipissing beach ; and the lake which it bounded, and which was nearly 

 coterminous with the present Lakes Superior, Michigan and Huron, is called the 

 Nipissing Great Lake. It lies in a very even plane which diverges from the 

 present lake level at the rate of nearly seven inches to the mile in a direction 

 about N 27° E. Its maximum elevation is 110 to 115 feet above Lake Superior, 

 and this at Peninsular Harbour; at North Bay it is about 120 feet above 

 Georgian Bay. It meets the present surface of Lake Huron at points nearly 

 opposite the mouth of Saginaw Bay ; of Lake Michigan near Traverse and Green 

 Bays, and of Lake Superior not far east from Duluth. Its plane projected would 

 pass about 25 feet under the present lake level at Duluth, 40 feet at Port Huron, 

 and 100 feet at Chicago. 



The land exposed between the Nipissing beach and the present water margin is 

 in some places a number of miles in width. It exhibits the same evidences of 

 newness as those found in the uplifted area of the Champlain submergence. 

 Shells found in it are iu a similar state of preservation. Kiver channels which 

 cross it are manifestly in the early stages of erosive work. Notable among these 

 is the Nipigon. The inference is strong that the Nipissing Great Lake period was 

 contemporaneous with the Champlain submergence, and that during that time the 

 upper Great Lakes had their outlet by way of the Nipissing pass and Ottawa 

 river. 



If this is true there remained only the discharge of Lake Erie to occupy the 

 Niagara. This is at present about one-ninth of the total volume of the river. 

 As the work of this feeble stream we can account for the narrow and shallow 

 gorge of the Whirlpool rapids. 



The Champlain Uplift simultaneously uncovered the floor of the Champlain 

 sea, raised the Nipissing beach at the north-east and submerged it at the south- 

 west, closed the Nipissing outlet and opened that at Port Huron, turned the 

 entire discharge of the Great Lakes into the Niagara river, and inaugurated the 



