RESULTS 227 



The probable errors in observation might reach a variation of 0.05 

 foot. It will be seen that there was no difference of level at the two 

 localities for the quinquennial periods, one ending with 1859 and the 

 other with 1900, or practically even with 1910. Variations may be seen 

 in the early years. These would indicate a sinking at Port Colborne 

 more than at Cleveland, and a rise again to the normal state if they 

 could be attributed to earth-movements. From the full study it is ap- 

 parent that there has been no change of level in 57 years, although there 

 had been such great deformation at an earlier date. The present time is 

 one of rest, as is also shown by Dr. D. W. Johnson's present fixity of the 

 border of the continent, in contrast with the recent great elevation dur- 

 ing the time of making the submarine canyons, such as those of the ex- 

 tended Hudson River and Gulf of Saint Lawrence. 



These results disprove my original suggestion (1894:) that the Xiagara 

 discharge would be turned into the Mississippi in the not distant future. 

 This idea was expanded into a monograph 14 on earth-movements by Dr. 

 (i. K. Gilbert, who used the fluctuations of the lakes; but in so doing he 

 took the levels of a few isolated days, irregularly selected. The erroneous 

 results derived therefrom have been widely quoted, but the table given 

 above contains the proof of the present stability of the lake region. 15 



Results 



By triangulating the Iroquois, Algonquin, and other beaches, the dome 

 of the greatest deformation of the Great Lake region is found to be situ 

 a ted approximately in latitude 49° north, longitude 76° west, whence it 

 extends to latitude 50° 30' north, longitude 75° west. This is confirmed 

 by the course of the drainage of the highlands. It is the locality when 1 

 the "height of land" reaches its most southern lobe. 



Although the Adirondacks form an outlier of the Laurentian Moun- 

 tains, yet they have produced very little effect on the deformation of the 

 earth's crust, as shown by the raised beaches. This is seen on proceeding 

 eastward from the head of Lake Erie, where the old shorelines are still 

 almost horizontal. At the head of Lake Ontario the rise is 2 feel per 

 mile north 22° east; bui on approaching the 76th meridian the eastern 

 equivalenl in the warping entirely disappears, while thai in ihe north- 

 ward direction increases from 3 feel per mile in the Mohawk Valley to 6 

 feet per mile on nearing Ihe Saint Lawrence River. 



On passing Ihe 76th meridian the direction of ihe uplift becomes 



"Eighteenth Ann. Rept. r. s. Geological Purvey, pari n. isms. pp. 601 647. 

 1 • Kalis of Niagara, chapter 31. 



