.Science, Geology and Physics 



hypotheses have given zest to the investigations to the degree of 1S98 

 advancing our knowledge of the lake history. pencer 



In the survey of the beaches, besides the terrestrial deforma- 

 tion recorded, there seems to be no more important discovery 

 than when the writer found how the Huron, Michigan and 

 Superior waters (the Algonquin gulf or lake) originally emptied 

 to the northeastward of the Huron basin in place of discharging 

 into Lake Erie; after which, by the northeastern tilting of the 

 land, " the waters were backed southward and overflowed into 

 the Erie basin, thus making the Erie outlet of the upper lakes 

 to be of recent date." 1 This conclusion was established by the 

 survey of the Algonquin beach which recorded the necessary 

 tilting. The first survey was suspended near Balsam lake, where 

 an overflow was found; and, accordingly, in the original 

 announcement, the generalizations were not carried farther; 

 although there was a lower depression in the vicinity of Lake 

 Nipissing, which was shortly afterwards made use of by Prof. 

 Gilbert 2 and the writer. With the further elevation of the land, 

 the lower beaches — partly measured at that time (1887—8) — 

 represented the surface of the Algonquin water discharging by 

 the Nipissing route alone. 3 This has since been worked out by 

 Mr. Taylor. 4 



Co-existing with the Algonquin gulf or lake was the Lundy 

 gulf or lake, occupying part of the Erie basin, and extending 

 into the Ontario, having substantially the same level. Both of 

 these bodies of water extended much farther towards the north- 

 east than their successors, although more contracted in the oppo- 

 site directions — the effect of the more recent tilting of the land. 

 Prior to the existence of these separate bodies of water, higher 

 shore-lines were formed, and the great gulf or lake bounded by 



^roc. A. A. A. S., XXXVII, 1888, p. 199. 



2 Hist, of the Nipissing river. 



3 Deformation of the Algonquin beach, etc., cited before. 



4 Ancient strait of Nipissing. Taylor. Bull. Geol. Soc. Am., vol. V. 

 1893. 



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