164 \. (. LAWSON — Till PRE-PALEOZOIC SURFACE. 



Burface r< presents the locus to which rock decay had extended in depth. In 

 this view the ice .-imply removed the rotten rock, Bcouring ami polishing 

 tin fresh Burface upon which it rested, and the hummocky character is due 

 rather to the principles which govern the decay of rocks than to ice action, 

 which is only held responsible for laying the surface bare. All students of 

 glacial geology will concede that in both of these opinions there Is a certain 

 amount of truth, though much more in the Becond than in the fust. 



rvations, however, which the writer has been enabled to make 

 at odd times during the past few years, indicate that these hypotheses do not 

 afford u- the correct explanation of the hummocky aspect of the Archean 

 Burface, bul that the latter, in it- essentia] ami prominent features, long 

 antedates the glacial epoch, and was as characteristic of the surface upon 

 which the earliest Paleozoic sediments were deposited a.- of that upon which 

 the greal Canadian glacier rested in glacial times. These observations have 

 been made along the northern limit of the undisturbed Animikie and Nipigon 

 strata, where they resl direct ly upon the Archean surface, on the north shore 



I Superior, between < runflint lake <>n the international boundary and 

 the meridian of the Slate islands. The conclusions which they forced upon 

 the writer have been confirmed by an inquiry which he has made into the 

 condition- which prevail along the line of contact of the undisturbed Paleozoic 

 rock- u] the Archean in more eastern portion- of Canada. 



In a paper of the present compass it will scarcely he possible to do more 

 than indicate the localities where the evidence may be found, and to sketch 

 tin' latter at each place in -cant outlines. 



IH i I'll i \< >mi:n a -u Central Canada. 



I darts between tin Animikii >ni<l the Archean.— On the north side of 

 Gunflinl lake the superposition of the northern edge of the Animikie upon 

 the Archean is well seen. To the north of the edge of the Animikie for- 

 mation- the Archean rises in low hummocky hills, the ridges of which, when 

 these are present, coincide with the strike of the rock-. This hummocky 



surface may be walked over close up to the A nimikie. and it may be Been to 

 form an undulating surface upon which the latter rests. At the west end of 

 the lake, on the north Bide of Black-fly bay, on mining locations R. 315 and 

 l; 317, i- an outlier of the basal beds of the Animikie resting on a ridge of 



I urentiai -, with hollow.- sither Bide of it, and tin' Animikie al 



the bottom of that on the BOUth, the whole Bhowing very clearly that the 



present shape of the surface of the Laurentian was practically that upon 



which the Animikie was laid down. The direct repose of the tlat 



A nimikie upon t he upturnei of the Keewatin schists Is also observable 



a mile and three-quarters from the east end of the lake, and here the Burface 



