Xl PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Some islands on the north coast of this lake are described as stri- 

 kingly moutonnee. 



On Lake Huron the erratics abound, especially on the north side, 

 where the hard rocks are much striated and rounded. We need not 

 wonder that in 1824, their appearances were great mysteries to the 

 author. It appears singular that there should be no terraces in this 

 lake (so far as the author's observation extended), while there are so 

 many in Lake Superior. The difference of level of the two lakes 

 is only about 20 feet. This shows an irregularity either in the pro- 

 cess of deposition or of subsequent denudation, which would seem 

 to indicate an action far less gradual and uniform than ordinary diur- 

 nal action. 



On the east of Lake Huron, near to Lake Simcoe, the river Nota- 

 wasaga cuts through two remarkable freshwater beds filled with 

 JJniones associated with many small freshwater univalves, as Pla- 

 norbeSy Physce^ LymncecB, Melmiics, PaludincB, &c., all abundant in 

 the river at the present day. There are two of these beds, each 

 from 4 to 6 inches thick, and above are stratified beds of which the 

 whole thickness in some places is not less than 1 50 feet. 



Lake Erie is situated in the lowest part of the extensive tract south 

 of Lake Huron. This tract is formed of widely-extended beds of blue 

 and red clays with superincumbent beds of sand, which form the shores 

 of Lake Erie, forming banks and scarps of considerable elevation 

 throughout a distance, on the north shore, of nearly 300 miles. The 

 erratics are principally from Lake Huron. The more level as well 

 as the more distant erratics appear in all the lakes to have tra- 

 velled more or less in a southerly direction, indicating clearly the wide 

 generality of the principal cause to which the whole transport is re- 

 ferable. 



Lake Ontario is about 330 feet below the level of Lake Erie, the 

 Falls of Niagara, it will be recollected, being between the two lakes. 

 Several lofty ridges or terraces wander round this lake at different di- 

 stances, leaving a wide opening for the escape of its waters at its north- 

 eastern extremity. The shores of the lake are, in many parts, formed 

 of cliffs, sometimes 300 feet high (as near Toronto), of detrital matter, 

 in some cases coarse, in others finer and stratified, and frequently con- 

 taining erratic boulders. Many large erratics also exist on the sur- 

 face. 



In discussing these different phsenomena, the author divides the 

 whole detrital mass into loose detritus, and imbedded detritus. The 

 former he again subdivides into 



1 . Distant Erratics ; 



2. Near or Lake Erratics ; 



3. Native Debris. 



The prevalent courses of the distant erratics are southerly, but, as 

 is seen by the appended map, they vary from south-east to south-west. 

 I have already stated, that in the north of Europe blocks setting out 

 from a given point do not all proceed in the same direction, but that 

 the angle included between the extreme directions of radiation is a 

 considerable one, sometimes even larger than a right angle. The va- 



