ALGONQUIN ISOBASES 233 



(xeorgiaii Bay and Penetang Peninsula — Continued: 



Meaford 783 F. B. Tajior and J. W. Goldthwait, Cana- 

 dian Geological Survey. 1908. 



Clarksburg 769 Ditto. 



Mail- Mills 767 Ditto. 



Colwell 774 Ditto. 



Penetang 855 Ditto. 



Wyebridge 840 Ditto. 



Elmvale 829 Ditto. 



Coldwater 852 Ditto. 



Lake Simcoe district: 



Orillia 847 Ditto. 



Ore 811 Ditto. 



Barrie 785 Ditto. 



Holland Lauding 752 Ditto. 



Beaverton 822 Ditto. 



Kirkfield 883 Ditto. 



With hardly an exception these measurements were made with the wye- 

 leveL 



In regard to the data from localities east of Lake Huron and Georgian 

 Ba}^, it should be said that the altitude of the Algonquin Deach at most 

 of these places was measured by Dr. J. W. Spencer in 1887. With only 

 two or three exceptions the new measurements of 1908 agree with those 

 of Spencer, and bear witness to the accuracy of his work. 



Isobases for every 50 feet of uplift between and 300 have been 

 drawn with reference to these localities. That the isobases accord prop- 

 erly with the 60 stations whose measurements have just been tabulated 

 is easily seen on plate 5. The accordance would be found to be just as 

 good, however, if one selected at random any 60 of the 100 stations whose 

 positions are shown by the dots. Detailed work on large-scale maps, the 

 results of which have been published in other papers,^ testify to the 

 remarkably complete harmony between isobases and measurements. 



In preparing the following summary of the attitude of this warped 

 water-plane, such details as directions and rates of tilt have been worked 



^ .T. W. Goldthwait : rorrelation of the raised beaches on the west side of Lake 

 Michigan. Journal of Geologj% vol. 14, 1906, pp. 411-424. 



Abandoned shorelines of eastern Wisconsin. Bulletin of the Wisconsin Geological 

 and Natural History Survey, no. 17, 1907. 



A reconstruction of water-planes of the extinct glacial lakes in the Lake Michigan 

 basin. Journal of Geology, vol. 16, 1908, pp. 459-476. 



Preliminary report on measurements of altitude of the Algonquin and Nipissing 

 shorelines in Ontario. July 6-August 11. 1908. Geological Survey of Canada. Summary 

 Report of Director for 1908, pp. 112-114. 



An instrumental survey of the shorelines of the extinct lakes Algonquin and Nipis- 

 sing in southwestern Ontario. Geological Survey of Canada (in press). 



